Partial Approval and Partial Disapproval of Air Quality Implementation Plans and Determination of Attainment by the Attainment Date; California; San Joaquin Valley Serious Area and Section 189(d) Plan for Attainment of the 1997 24-Hour PM2.5, 53150-53184 [2021-20613]
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Federal Register / Vol. 86, No. 183 / Friday, September 24, 2021 / Proposed Rules
ENVIRONMENTAL PROTECTION
AGENCY
40 CFR Part 52
[EPA–R09–OAR–2021–0261; FRL–8969–01–
R9]
Partial Approval and Partial
Disapproval of Air Quality
Implementation Plans and
Determination of Attainment by the
Attainment Date; California; San
Joaquin Valley Serious Area and
Section 189(d) Plan for Attainment of
the 1997 24-Hour PM2.5 NAAQS
Environmental Protection
Agency (EPA).
ACTION: Proposed rule.
AGENCY:
The Environmental Protection
Agency (EPA) is proposing to approve
in part and disapprove in part portions
of a state implementation plan (SIP)
revision submitted by the State of
California to meet Clean Air Act (CAA
or ‘‘Act’’) requirements for the 1997 24hour fine particulate matter (PM2.5)
national ambient air quality standards
(NAAQS) in the San Joaquin Valley
nonattainment area. Specifically, the
EPA is proposing to approve all but the
contingency measure element of the
submitted SIP revision as meeting all
applicable Serious area and CAA
section 189(d) requirements for the 1997
24-hour PM2.5 NAAQS and is proposing
disapproval of the contingency measure
element. The EPA is also proposing to
determine that the San Joaquin Valley
air quality planning area has attained
the 1997 24-hour PM2.5 NAAQS. This
determination is based on sufficient,
quality-assured, and certified data for
2018–2020. Based on our proposed
finding that the San Joaquin Valley
nonattainment area has attained the
1997 24-hour PM2.5 NAAQS, we are
proposing to determine that the
requirement for contingency measures
will no longer apply to the San Joaquin
Valley nonattainment area for these
NAAQS. Thus, the EPA is proposing to
issue a protective finding for
transportation conformity
determinations for this proposed
disapproval.
SUMMARY:
Any comments on this proposal
must be received by October 25, 2021.
ADDRESSES: Submit your comments,
identified by Docket ID No. EPA–R09–
OAR–2021–0261 at https://
www.regulations.gov. For comments
submitted at Regulations.gov, follow the
online instructions for submitting
comments. Once submitted, comments
cannot be edited or removed from
Regulations.gov. The EPA may publish
DATES:
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any comment received to its public
docket. Do not submit electronically any
information you consider to be
Confidential Business Information (CBI)
or other information whose disclosure is
restricted by statute. Multimedia
submissions (e.g., audio or video) must
be accompanied by a written comment.
The written comment is considered the
official comment and should include
discussion of all points you wish to
make. The EPA will generally not
consider comments or comment
contents located outside of the primary
submission (i.e., on the web, cloud, or
other file sharing system). For
additional submission methods, please
contact the person identified in the FOR
FURTHER INFORMATION CONTACT section.
For the full EPA public comment policy,
information about CBI or multimedia
submissions, and general guidance on
making effective comments, please visit
https://www.epa.gov/dockets/
commenting-epa-dockets. If you need
assistance in a language other than
English or if you are a person with
disabilities who needs a reasonable
accommodation at no cost to you, please
contact the person identified in the FOR
FURTHER INFORMATION CONTACT section.
FOR FURTHER INFORMATION CONTACT:
Ashley Graham, Air Planning Office
(ARD–2), EPA Region IX, 75 Hawthorne
Street, San Francisco, CA 94105, (415)
972–3877, or by email at
graham.ashleyr@epa.gov.
SUPPLEMENTARY INFORMATION:
Throughout this document, ‘‘we,’’ ‘‘us,’’
or ‘‘our’’ refer to the EPA.
Table of Contents
I. Background for Proposed Action
A. PM2.5 NAAQS
B. San Joaquin Valley PM2.5 Designations,
Classifications, and SIP Revisions
II. Summary and Completeness Review of the
San Joaquin Valley PM2.5 Plan
A. 2018 PM2.5 Plan
B. Valley State SIP Strategy
III. Clean Air Act Requirements for PM2.5
Serious Area Plans and for Serious PM2.5
Areas That Fail To Attain
A. Requirements for PM2.5 Serious Area
Plans
B. Requirements for Serious PM2.5 Areas
That Fail To Attain
IV. Review of the San Joaquin Valley PM2.5
Plan for the 1997 24-Hour PM2.5 NAAQS
A. Emissions Inventories
B. PM2.5 Precursors
C. Attainment Plan Control Strategy
D. Attainment Demonstration and
Modeling
E. Reasonable Further Progress and
Quantitative Milestones
F. Contingency Measures
G. Motor Vehicle Emission Budgets
H. Nonattainment New Source Review
Requirements Under CAA Section 189(e)
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V. Determination of Attainment by the
Attainment Date
A. Requirements for Attainment
Determinations
B. Monitoring Network Considerations
C. Data Considerations and Proposed
Determination
VI. Summary of Proposed Action and
Request for Public Comment
VII. Statutory and Executive Order Reviews
I. Background for Proposed Action
A. PM2.5 NAAQS
Under section 109 of the CAA, the
EPA has established NAAQS for certain
pervasive air pollutants (referred to as
‘‘criteria pollutants’’) and conducts
periodic reviews of the NAAQS to
determine whether they should be
revised or whether new NAAQS should
be established.
On July 18, 1997, the EPA revised the
NAAQS for particulate matter by
establishing new NAAQS for particles
with an aerodynamic diameter less than
or equal to a nominal 2.5 micrometers
(PM2.5).1 The EPA established primary
and secondary annual and 24-hour
standards for PM2.5.2 The annual
primary and secondary standards were
set at 15.0 micrograms per cubic meter
(mg/m3), based on a three-year average of
annual mean PM2.5 concentrations, and
the 24-hour primary and secondary
standards were set at 65 mg/m3, based on
the three-year average of the 98th
percentile of 24-hour PM2.5
concentrations at each monitoring site
within an area.3 Collectively, we refer
herein to the 1997 24-hour and annual
PM2.5 NAAQS as the ‘‘1997 PM2.5
NAAQS’’ or ‘‘1997 PM2.5 standards.’’
On October 17, 2006, the EPA revised
the level of the 24-hour PM2.5 NAAQS
to 35 mg/m3,4 and on January 15, 2013,
the EPA revised the level of the primary
annual PM2.5 NAAQS to 12.0 mg/m3.5
Even though the EPA lowered the 24hour and annual PM2.5 NAAQS, the
1997 24-hour PM2.5 NAAQS remain in
effect and the 1997 primary annual
PM2.5 NAAQS remains in effect in areas
designated nonattainment for that
NAAQS.6
The EPA established the 1997 PM2.5
NAAQS after considering substantial
1 62
FR 38652.
a given air pollutant, ‘‘primary’’ NAAQS are
those determined by the EPA as requisite to protect
the public health, allowing an adequate margin of
safety, and ‘‘secondary’’ standards are those
determined by the EPA as requisite to protect the
public welfare from any known or anticipated
adverse effects associated with the presence of such
air pollutant in the ambient air. See CAA section
109(b).
3 40 CFR 50.7.
4 71 FR 61144.
5 78 FR 3086.
6 40 CFR 50.13(d).
2 For
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evidence from numerous health studies
demonstrating that serious health effects
are associated with exposures to PM2.5
concentrations above these levels.
Epidemiological studies have shown
statistically significant correlations
between elevated PM2.5 levels and
premature mortality. Other important
health effects associated with PM2.5
exposure include aggravation of
respiratory and cardiovascular disease
(as indicated by increased hospital
admissions, emergency room visits,
absences from school or work, and
restricted activity dates), changes in
lung function and increased respiratory
symptoms, and new evidence for more
subtle indicators of cardiovascular
health. Individuals particularly
sensitive to PM2.5 exposure include
older adults, people with heart and lung
disease, and children.7
Sources can emit PM2.5 directly into
the atmosphere as a solid or liquid
particle (primary PM2.5 or direct PM2.5),
or PM2.5 can form in the atmosphere
(secondary PM2.5) as a result of various
chemical reactions from precursor
emissions of nitrogen oxides (NOX),
sulfur oxides (SOX), volatile organic
compounds, and ammonia.8
miles from north to south and averaging
80 miles wide, it is partially enclosed by
the Coast Mountain range to the west,
the Tehachapi Mountains to the south,
and the Sierra Nevada range to the east.
Under State law, the San Joaquin Valley
Unified Air Pollution Control District
(SJVUAPCD or ‘‘District’’) has primary
responsibility for developing plans to
provide for attainment of the NAAQS in
this area. The District works
cooperatively with the California Air
Resources Board (CARB) in preparing
attainment plans. Authority for
regulating sources under state
jurisdiction in the San Joaquin Valley is
split under State law between the
District, which generally has
responsibility for regulating stationary
and area sources, and CARB, which
generally has responsibility for
regulating mobile sources.
At the time of the initial designations
for the 1997 PM2.5 NAAQS, the EPA
interpreted the CAA to require
implementation of the NAAQS under
the general nonattainment plan
requirements of subpart 1.12 Under
subpart 1, states were required to submit
nonattainment plan SIP submissions
within three years of the effective date
B. San Joaquin Valley PM2.5
of designations, that, among other
Designations, Classifications, and SIP
things, provided for implementation of
Revisions
reasonably available control measures
Following promulgation of a new or
(RACM), reasonable further progress
revised NAAQS, the EPA is required
(RFP), contingency measures, and a
under CAA section 107(d) to designate
modeled attainment demonstration
areas throughout the nation as attaining showing attainment of the NAAQS as
or not attaining the NAAQS. Effective
expeditiously as practicable but no later
April 5, 2005, the EPA established the
than five years from the designation (in
initial air quality designations for the
this instance, no later than April 5,
1997 24-hour and annual PM2.5 NAAQS, 2010) unless the state justified an
using air quality monitoring data for the attainment date extension of up to five
three-year periods of 2001–2003 and
years.13
2002–2004.9 The EPA designated the
Between 2007 and 2011, California
San Joaquin Valley as nonattainment for
both the 1997 24-hour PM2.5 NAAQS (65 submitted six SIP revisions to address
nonattainment area planning
mg/m3) and the 1997 annual PM2.5
requirements for the 1997 24-hour and
NAAQS (15.0 mg/m3).10
annual PM2.5 NAAQS in the San Joaquin
The San Joaquin Valley PM2.5
Valley,14 which we refer to collectively
nonattainment area encompasses over
as the ‘‘2008 PM2.5 Plan.’’ On November
23,000 square miles and includes all or
9, 2011, the EPA approved the portions
part of eight counties: San Joaquin,
of the 2008 PM2.5 Plan, as revised in
Stanislaus, Merced, Madera, Fresno,
2009 and 2011, that addressed
Tulare, Kings, and the valley portion of
Kern.11 The area is home to four million attainment of the 1997 24-hour and
people and is one of the nation’s leading annual PM2.5 NAAQS in the San Joaquin
agricultural regions. Stretching over 250 Valley PM2.5 nonattainment area, except
for the attainment contingency
7 EPA, Air Quality Criteria for Particulate Matter,
measures, which we disapproved.15 We
No. EPA/600/P–99/002aF and EPA/600/P–99/
also granted the State’s request to
002bF, October 2004.
extend the attainment deadline for the
8
For example, see 72 FR 20586, 20589 (April 25,
2007).
9 70 FR 944 (January 5, 2005).
10 40 CFR 81.305.
11 For a precise description of the geographic
boundaries of the San Joaquin Valley nonattainment
area, see 40 CFR 81.305.
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12 72
FR 20586.
sections 172(a)(2), 172(c)(1), 172(c)(2),
and 172(c)(9).
14 76 FR 69896, n. 2 (November 9, 2011).
15 Id. at 69924.
13 CAA
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53151
1997 PM2.5 NAAQS in the San Joaquin
Valley to April 5, 2015.16
Following a January 4, 2013 decision
of the U.S. Court of Appeals for the D.C.
Circuit (‘‘D.C. Circuit’’) remanding the
EPA’s 2007 implementation rule for the
1997 PM2.5 NAAQS,17 the EPA
published a final rule on June 2, 2014,
classifying the San Joaquin Valley as a
Moderate nonattainment area for the
1997 24-hour and annual PM2.5 NAAQS
under subpart 4, part D of title I of the
Act.18 In this action, the EPA
acknowledged that states must meet
both subpart 1 and subpart 4
requirements in nonattainment plan SIP
submissions for the 1997 24-hour and
annual PM2.5 NAAQS and provided
states with additional time to
supplement or withdraw and resubmit
any pending nonattainment plan SIP
submissions.
Effective May 7, 2015, the EPA
reclassified the San Joaquin Valley as a
Serious nonattainment area for the 1997
PM2.5 NAAQS based on the
determination that the State could not
practicably attain these NAAQS in the
San Joaquin Valley nonattainment area
by the latest statutory Moderate area
attainment date, i.e., April 5, 2015.19
Upon reclassification as a Serious area,
the State became subject to the
requirement of CAA section 188(c)(2) to
attain the 1997 PM2.5 NAAQS, as
expeditiously as practicable but no later
than ten years after designation, i.e., by
no later than December 31, 2015.
California submitted its 1997 PM2.5
Serious area plan for the San Joaquin
Valley in two submissions dated June
25, 2015 and August 13, 2015, including
a request under section 188(e) to extend
the attainment date for the 1997 24-hour
PM2.5 NAAQS by three years (to
December 31, 2018) and to extend the
attainment date for the 1997 annual
PM2.5 NAAQS by five years (to
December 31, 2020). On February 9,
2016, the EPA proposed to approve
most of the Serious area plan and to
16 Id.
17 Natural Resources Defense Council v. EPA, 706
F.3d. 428 (D.C. Cir. 2013) (‘‘NRDC’’). In NRDC, the
court held that the EPA erred in implementing the
1997 PM2.5 standards solely pursuant to the general
implementation requirements of subpart 1, without
also considering the requirements specific to
nonattainment areas for particles less than or equal
to 10 mm in diameter (PM10) in subpart 4, part D
of title I of the CAA. The court reasoned that the
plain meaning of the CAA requires implementation
of the 1997 PM2.5 standards under subpart 4
because PM2.5 falls within the statutory definition
of PM10 and is thus subject to the same statutory
requirements as PM10. The court remanded the rule,
without vacatur, and instructed the EPA ‘‘to
repromulgate these rules pursuant to Subpart 4
consistent with this opinion.’’
18 79 FR 31566.
19 80 FR 18528 (April 7, 2015).
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grant the State’s request for extensions
of the December 31, 2015 attainment
date.20 However, on October 6, 2016,
after considering public comments, the
EPA denied California’s request for
these extensions of the attainment
dates.21 Consequently, on November 23,
2016, the EPA determined that the San
Joaquin Valley had failed to attain the
1997 24-hour and annual PM2.5 NAAQS
by the December 31, 2015 Serious area
attainment date.22 This determination
triggered a requirement for California to
submit a new SIP submission for the
1997 24-hour and annual PM2.5 NAAQS
for the San Joaquin Valley that satisfies
the requirements of CAA section 189(d).
The statutory deadline for this
additional SIP submission was
December 31, 2016. The EPA did not
finalize the actions proposed on
February 9, 2016, with respect to the
submitted Serious area plan.23
On December 6, 2018, the EPA
determined that California had failed to
submit a complete section 189(d)
attainment plan for the 1997 24-hour
and annual PM2.5 NAAQS, among other
required SIP submissions for the San
Joaquin Valley, by the statutory
deadlines.24 This finding, which
became effective on January 7, 2019,
triggered clocks under CAA section
179(a) for the application of emissions
offset sanctions 18 months after the
finding, and highway funding sanctions
6 months thereafter, unless the EPA
affirmatively determined that the State
has made a complete SIP submission
addressing the identified failure to
submit deficiencies.25 The finding also
triggered the obligation under CAA
section 110(c) for the EPA to promulgate
a federal implementation plan no later
than two years after the finding, unless
the State has submitted, and the EPA
has approved, the required SIP
submission.26
On May 10, 2019, CARB made SIP
submissions intended to address the
Serious area nonattainment plan and
CAA section 189(d) requirements for the
1997 24-hour and annual PM2.5 NAAQS,
among other requirements for the 2006
and 2012 PM2.5 NAAQS.27 CARB
20 81 FR 6936. California’s request for extension
of the Serious Area attainment date for the San
Joaquin Valley accompanied its Serious Area
attainment plan for the 1997 PM2.5 NAAQS and
related motor vehicle emission budgets, submitted
June 25, 2015 and August 13, 2015, respectively.
21 81 FR 69396.
22 81 FR 84481.
23 81 FR 69396, 69400.
24 83 FR 62720.
25 Id. at 62723.
26 Id.
27 Letter dated May 9, 2019, from Richard Corey,
Executive Officer, CARB, to Mike Stoker, Regional
Administrator, EPA Region 9. The letter clarifies
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clarified in its May 10, 2019 letter that
these new SIP submissions superseded
past submissions to the EPA that the
agency had not yet acted on for the 1997
PM2.5 NAAQS, including the 2015
Serious area attainment plan
submissions. On June 24, 2020, the EPA
issued a letter finding these submissions
complete and terminating the sanctions
clocks under CAA section 179(a).28 The
portions of these SIP submissions that
pertain to the 1997 24-hour PM2.5
NAAQS are the subject of this proposal.
II. Summary and Completeness Review
of the San Joaquin Valley PM2.5 Plan
The EPA is proposing action on
portions of two SIP submissions made
by CARB to address nonattainment plan
requirements for the 1997 24-hour PM2.5
NAAQS in the San Joaquin Valley.
Specifically, the EPA is proposing to act
on those portions of the following two
SIP submissions that pertain to the 1997
24-hour PM2.5 NAAQS: (i) The ‘‘2018
Plan for the 1997, 2006, and 2012 PM2.5
Standards,’’ adopted by the SJVUAPCD
on November 15, 2018, and by CARB on
January 24, 2019 (‘‘2018 PM2.5 Plan’’); 29
and (ii) the ‘‘San Joaquin Valley
Supplement to the 2016 State Strategy
for the State Implementation Plan,’’
adopted by CARB on October 25, 2018
(‘‘Valley State SIP Strategy’’). CARB
submitted the 2018 PM2.5 Plan and
Valley State SIP Strategy to the EPA as
a revision to the California SIP on May
10, 2019.30 We refer to these two SIP
that the 2018 PM2.5 Plan supersedes past submittals
to the EPA that the agency has not yet acted on for
the 1997 PM2.5 standards, including the 2015 Plan
for the 1997 Standard (submitted by CARB on June
25, 2015) and motor vehicle emission budgets
(submitted by CARB August 13, 2015).
28 Letter dated June 24, 2020, from Elizabeth J.
Adams, Director, Air and Radiation Division, EPA
Region IX, to Richard Corey, Executive Officer,
CARB, Subject: ‘‘RE: Completeness Finding for
State Implementation Plan (SIP) Submissions for
San Joaquin Valley for the 1997, 2006, and 2012
Fine Particulate Matter (PM2.5) National Ambient
Air Quality Standards (NAAQS) and Termination of
Clean Air Act (CAA) Sanction Clocks.’’
29 The 2018 PM
2.5 Plan was developed jointly by
CARB and the District.
30 Letter dated May 9, 2019, from Richard Corey,
Executive Officer, CARB, to Mike Stoker, Regional
Administrator, EPA Region 9. The EPA previously
acted on those portions of the ‘‘2018 Plan for the
1997, 2006, and 2012 PM2.5 Standards’’ and the
‘‘San Joaquin Valley Supplement to the 2016 State
Strategy for the State Implementation Plan’’ that
pertain to the 2006 PM2.5 NAAQS (85 FR 44192,
July 22, 2020), and proposed action on those
portions pertaining to the 1997 annual PM2.5
NAAQS (86 FR 38652, July 22, 2021) and 2012
annual PM2.5 NAAQS (86 FR 49100, September 1,
2021). The EPA is not, at this time, taking any
action on those portions that pertain to the 1997
annual PM2.5 NAAQS or the 2012 annual PM2.5
NAAQS. We intend to act on these portions of the
submitted SIP revisions in subsequent rulemakings.
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submissions collectively as the ‘‘SJV
PM2.5 Plan’’ or ‘‘Plan.’’
The SJV PM2.5 Plan addresses the
Serious area nonattainment plan and
CAA section 189(d) requirements for the
1997 24-hour and annual PM2.5 NAAQS
in the San Joaquin Valley, including the
State’s demonstration that the area
would attain the 1997 24-hour PM2.5
NAAQS by December 31, 2020. In this
proposal, the EPA is proposing action
only on those portions of the SJV PM2.5
Plan that pertain to the 1997 24-hour
PM2.5 NAAQS. The EPA is acting on the
portions of the SJV PM2.5 Plan that
pertain to the 1997 annual PM2.5
NAAQS and subsequent PM2.5 NAAQS
in separate rulemakings.
CAA sections 110(a)(1) and (2) and
110(l) require each state to provide
reasonable public notice and
opportunity for public hearing prior to
the adoption and submission of a SIP or
SIP revision to the EPA. To meet this
requirement, every SIP submission must
include evidence that the state provided
adequate public notice and an
opportunity for a public hearing
consistent with the EPA’s implementing
regulations in 40 CFR 51.102.
CAA section 110(k)(1)(B) requires the
EPA to determine whether a SIP
submission is complete within 60 days
of receipt. This section also provides
that any plan that the EPA has not
affirmatively determined to be complete
or incomplete will become complete by
operation of law six months after the
date of submission. The EPA’s SIP
completeness criteria are found in 40
CFR part 51, Appendix V.
A. 2018 PM2.5 Plan
The following portions of the 2018
PM2.5 Plan and related support
documents address both the Serious
area nonattainment plan requirements
in CAA section 189(b) and the CAA
section 189(d) requirements for the 1997
24-hour PM2.5 NAAQS in the San
Joaquin Valley: (i) Chapter 4
(‘‘Attainment Strategy for PM2.5’’); (ii)
Chapter 5 (‘‘Demonstration of Federal
Requirements for 1997 PM2.5
Standards’’); 31 (iii) numerous
appendices to the 2018 PM2.5 Plan; (iv)
31 Chapter 6 (‘‘Demonstration of Federal
Requirements for the 2006 PM2.5 Standard: Serious
Plan and Extension Request’’) and Chapter 7
(‘‘Demonstration of Federal Requirements for the
2012 PM2.5 Standard’’) of the 2018 PM2.5 Plan
pertain to the 2006 PM2.5 NAAQS and the 2012
PM2.5 NAAQS, respectively. The EPA previously
acted on those portions of the Plan that pertain to
the 2006 PM2.5 NAAQS (85 FR 44192), and
proposed action on those portions pertaining to the
2012 annual PM2.5 NAAQS (86 FR 49100). The EPA
intends to take further action on those portions that
pertain to the 2012 annual PM2.5 NAAQS in
separate rulemakings.
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CARB’s ‘‘Staff Report, Review of the San
Joaquin Valley 2018 Plan for the 1997,
2006, and 2012 PM2.5 Standards,’’
release date December 21, 2018 (‘‘CARB
Staff Report’’); 32 and (v) the State’s and
District’s board resolutions adopting the
2018 PM2.5 Plan (CARB Resolution 19–
1 and SJVUAPCD Governing Board
Resolution 18–11–16).33
The appendices to the 2018 PM2.5
Plan that address the requirements for
the 1997 24-hour PM2.5 NAAQS include:
(i) Appendix A (‘‘Ambient PM2.5 Data
Analysis’’); (ii) Appendix B (‘‘Emissions
Inventory’’); (iii) Appendix C
(‘‘Stationary Source Control Measure
Analyses’’); (iv) Appendix D (‘‘Mobile
Source Control Measure Analyses’’); (v)
Appendix G (‘‘Precursor
Demonstration’’); (vi) Appendix H
(‘‘RFP, Quantitative Milestones, and
Contingency’’); 34 (vii) Appendix I
(‘‘New Source Review and Emission
Reduction Credits’’); (viii) Appendix J
(‘‘Modeling Emission Inventory’’); (ix)
Appendix K (‘‘Modeling Attainment
Demonstration’’); and (x) Appendix L
(‘‘Modeling Protocol’’).
The District provided public notice
and opportunity for public comment
prior to its November 15, 2018 public
hearing on and adoption of the 2018
PM2.5 Plan.35 CARB also provided
public notice and opportunity for public
comment prior to its January 24, 2019
public hearing on and adoption of the
2018 PM2.5 Plan.36 The SIP submission
includes proof of publication of notices
for the respective public hearings. It also
includes copies of the written and oral
comments received during the State’s
32 Letter dated December 11, 2019, from Richard
Corey, Executive Officer, CARB, to Mike Stoker,
Regional Administrator, EPA Region 9, transmitting
the CARB Staff Report [on the 2018 PM2.5 Plan]. The
CARB Staff Report includes CARB’s review of,
among other things, the 2018 PM2.5 Plan’s control
strategy and attainment demonstration.
33 CARB Resolution 19–1, ‘‘2018 PM
2.5 State
Implementation Plan for the San Joaquin Valley,’’
January 24, 2019, and SJVUAPCD Governing Board
Resolution 18–11–16, ‘‘Adopting the [SJVUAPCD]
2018 Plan for the 1997, 2006, and 2012 PM2.5
Standards,’’ November 15, 2018.
34 Appendix H to 2018 PM
2.5 Plan, submitted
February 11, 2020 via the EPA State Planning
Electronic Collaboration System. Following the
identification of a transcription error in the RFP
tables of Appendix H, on February 11, 2020, the
State submitted a revised version of Appendix H
that corrects the transcription error and provides
additional information on the RFP demonstration.
All references to Appendix H in this proposed rule
are to the revised version submitted on February 11,
2020, which replaces the version submitted with
the 2018 PM2.5 Plan on May 10, 2019.
35 SJVUAPCD, ‘‘Notice of Public Hearing for
Adoption of Proposed 2018 PM2.5 Plan for the 1997,
2006, and 2012 Standards,’’ October 16, 2018, and
SJVUAPCD Governing Board Resolution 18–11–16.
36 CARB, ‘‘Notice of Public Meeting to Consider
the 2018 PM2.5 State Implementation Plan for the
San Joaquin Valley,’’ December 21, 2018, and CARB
Resolution 19–1.
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and District’s public review processes
and the agencies’ responses thereto.37
Therefore, we find that the 2018 PM2.5
Plan meets the procedural requirements
for public notice and hearing in CAA
sections 110(a) and 110(l) and 40 CFR
51.102. The 2018 PM2.5 Plan became
complete by operation of law on
November 10, 2019.
B. Valley State SIP Strategy
CARB developed the ‘‘Revised
Proposed 2016 State Strategy for the
State Implementation Plan’’ (‘‘2016
State Strategy’’) to support attainment
planning in the San Joaquin Valley and
Los Angeles-South Coast Air Basin
(‘‘South Coast’’) ozone nonattainment
areas.38 In its resolution adopting the
2016 State Strategy (CARB Resolution
17–7), the Board found that the 2016
State Strategy would achieve 6 tons per
day (tpd) of NOX emissions reductions
and 0.1 tpd of direct PM2.5 emissions
reductions in the San Joaquin Valley by
2025 and directed CARB staff to work
with the SJVUAPCD to identify
additional reductions from sources
under District regulatory authority as
part of a comprehensive plan to attain
all of the PM2.5 NAAQS in the San
Joaquin Valley and to return to the
Board with a commitment to achieve
additional emissions reductions from
mobile sources.39
CARB responded to this resolution by
developing and adopting the ‘‘San
Joaquin Valley Supplement to the 2016
State Strategy for the State
Implementation Plan’’ (‘‘Valley State
SIP Strategy’’) to support the 2018 PM2.5
Plan. The State’s May 10, 2019 SIP
submission incorporates by reference
the Valley State SIP Strategy as adopted
by CARB on October 25, 2018 and
submitted to the EPA on November 16,
2018.40
The Valley State SIP Strategy includes
an ‘‘Introduction’’ (Chapter 1), a chapter
on ‘‘Measures’’ (Chapter 2), and a
‘‘Supplemental State Commitment from
37 CARB, ‘‘Board Meeting Comments Log,’’ March
29, 2019; J&K Court Reporting, LLC, ‘‘Meeting, State
of California Air Resources Board,’’ January 24,
2019 (transcript of CARB’s public hearing), and
2018 PM2.5 Plan, Appendix M (‘‘Summary of
Significant Comments and Responses’’).
38 The EPA has approved certain commitments
made by CARB in the 2016 State Strategy for
purposes of attaining the ozone NAAQS in the San
Joaquin Valley and South Coast ozone
nonattainment areas (see, e.g., 84 FR 3302 (February
12, 2019) and 84 FR 52005 (October 1, 2019)) and
for attaining the 2006 PM2.5 NAAQS in the San
Joaquin Valley (85 FR 44192).
39 CARB Resolution 17–7, ‘‘2016 State Strategy for
the State Implementation Plan,’’ March 23, 2017, 6–
7.
40 Letter dated May 9, 2019, from Richard Corey,
Executive Officer, CARB, to Mike Stoker, Regional
Administrator, EPA Region 9.
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the Proposed State Measures for the
Valley’’ (Chapter 3). Much of the
content of the Valley State SIP Strategy
is reproduced in Chapter 4 (‘‘Attainment
Strategy for PM2.5’’) of the 2018 PM2.5
Plan.41 The Valley State SIP Strategy
also includes CARB Resolution 18–49,
which, among other things, commits
CARB to achieve specific amounts of
NOX and PM2.5 emissions reductions by
specific years, for purposes of attaining
the PM2.5 NAAQS in the San Joaquin
Valley.42
CARB provided the required public
notice and opportunity for public
comment prior to its October 25, 2018
public hearing on and adoption of the
Valley State SIP Strategy.43 The SIP
submission includes proof of
publication of the public notice for this
public hearing. It also includes copies of
the written and oral comments received
during the State’s public review process
and CARB’s responses thereto.44
Therefore, we find that the Valley State
SIP Strategy meets the procedural
requirements for public notice and
hearing in CAA sections 110(a) and
110(l) and 40 CFR 51.102. The Valley
State SIP Strategy became complete by
operation of law on November 10, 2019.
III. Clean Air Act Requirements for
PM2.5 Serious Area Plans and for
Serious PM2.5 Areas That Fail To Attain
A. Requirements for PM2.5 Serious Area
Plans
Upon reclassification of a Moderate
nonattainment area as a Serious
nonattainment area under subpart 4 of
part D, title I of the CAA, the Act
requires the state to make a SIP
submission that addresses the following
Serious nonattainment area
requirements: 45
1. A comprehensive, accurate, current
inventory of actual emissions from all
sources of PM2.5 and PM2.5 precursors in
the area (CAA section 172(c)(3));
41 For example, Table 2 (proposed mobile source
measures and schedule), Table 3 (emissions
reductions from proposed mobile source measures),
and Table 4 (summary of emission reduction
measures) of the Valley State SIP Strategy
correspond to tables 4–8, 4–9, and 4–7,
respectively, of the 2018 PM2.5 Plan, Chapter 4.
42 CARB Resolution 18–49, ‘‘San Joaquin Valley
Supplement to the 2016 State Strategy for the State
Implementation Plan,’’ October 25, 2018, 5.
43 CARB, ‘‘Notice of Public Meeting to Consider
the San Joaquin Valley Supplement to the 2016
State Strategy for the State Implementation Plan,’’
September 21, 2018, and CARB Resolution 18–49.
44 CARB, ‘‘Board Meeting Comments Log,’’
November 2, 2018 and compilation of written
comments; and J&K Court Reporting, LLC,
‘‘Meeting, State of California Air Resources Board,’’
October 25, 2018 (transcript of CARB’s public
hearing).
45 40 CFR 51.1003(b)(1); 81 FR 58010, 58074–
58075 (August 24, 2016).
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2. Provisions to assure that the best
available control measures (BACM),
including best available control
technology (BACT), for the control of
direct PM2.5 and PM2.5 precursors shall
be implemented no later than four years
after the area is reclassified (CAA
section 189(b)(1)(B));
3. A demonstration (including air
quality modeling) that the plan provides
for attainment as expeditiously as
practicable but no later than the end of
the tenth calendar year after designation
as a nonattainment area (i.e., December
31, 2015, for the San Joaquin Valley for
the 1997 PM2.5 NAAQS);
4. Plan provisions that require RFP
(CAA section 172(c)(2));
5. Quantitative milestones that are to
be achieved every three years until the
area is redesignated attainment and that
demonstrate RFP toward attainment by
the applicable date (CAA section
189(c));
6. Provisions to assure that control
requirements applicable to major
stationary sources of PM2.5 also apply to
major stationary sources of PM2.5
precursors, except where the state
demonstrates to the EPA’s satisfaction
that such sources do not contribute
significantly to PM2.5 levels that exceed
the standard in the area (CAA section
189(e)); 46
7. Contingency measures to be
implemented if the area fails to meet
RFP or to attain by the applicable
attainment date (CAA section 172(c)(9));
and
8. A revision to the nonattainment
new source review (NSR) program to
lower the applicable ‘‘major stationary
source’’ 47 thresholds from 100 tons per
year (tpy) to 70 tpy (CAA section
189(b)(3)).
Serious area plans must also satisfy
the requirements for Moderate area
plans in CAA section 189(a), to the
extent the state has not already met
those requirements in the Moderate area
plan submitted for the area.48 In
46 As discussed in section IV.H, California
submitted nonattainment NSR SIP revisions to
address the subpart 4 requirements for the San
Joaquin Valley Serious PM2.5 nonattainment area on
November 20, 2019. We are not proposing any
action on this submission at this time. We will act
on this submission through a separate rulemaking,
as appropriate.
47 For any Serious area, the terms ‘‘major source’’
and ‘‘major stationary source’’ include any
stationary source that emits or has the potential to
emit at least 70 tons per year of PM2.5. CAA section
189(b)(3) and 40 CFR 51.165(a)(1)(iv)(A)(1)(vii) and
(viii) (defining ‘‘major stationary source’’ in serious
PM2.5 nonattainment areas).
48 Because the EPA has not previously approved
a SIP submission for the San Joaquin Valley as
meeting the subpart 4 RACM Moderate area
planning requirement under CAA section 189 for
the 1997 24-hour PM2.5 NAAQS, the EPA is
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addition, the Serious area plan must
meet the general requirements
applicable to all SIP submissions under
section 110 of the CAA, including the
requirement to provide necessary
assurances that the implementing
agencies have adequate personnel,
funding, and authority under section
110(a)(2)(E); and the requirements
concerning enforcement provisions in
section 110(a)(2)(C).
B. Requirements for Serious PM2.5 Areas
That Fail To Attain
In the event that a Serious area fails
to attain the PM2.5 NAAQS by the
applicable attainment date, CAA section
189(d) requires that ‘‘the State in which
such area is located shall, after notice
and opportunity for public comment,
submit within 12 months after the
applicable attainment date, plan
revisions which provide for attainment
of the . . . standard . . .’’ An
attainment plan under section 189(d)
must, among other things, demonstrate
expeditious attainment of the NAAQS
within the time period provided under
CAA section 179(d)(3) and provide for
annual reductions in emissions of direct
PM2.5 or a PM2.5 plan precursor
pollutant within the area of not less
than five percent per year from the most
recent emissions inventory for the area
until attainment.49 In addition to the
requirement to submit control measures
providing for a five percent reduction in
emissions of certain pollutants on an
annual basis, the EPA interprets CAA
section 189(d) as requiring a state to
submit an attainment plan that includes
the same basic statutory plan elements
that are required for other attainment
plans.50
Specifically, a state must submit to
the EPA its plan to meet the
requirements of CAA section 189(d) in
the form of a complete attainment plan
submission that includes the following
elements: 51
1. A comprehensive, accurate, current
inventory of actual emissions from all
sources of PM2.5 and PM2.5 precursors in
the area;
2. A Serious area plan control strategy
that ensures that BACM, including
BACT, for the control of direct PM2.5
and PM2.5 precursors are implemented
in the area;
3. Additional measures (beyond those
already adopted in previous
evaluating relevant portions of the SJV PM2.5 Plan
for compliance with these requirements, in addition
to the requirements of CAA sections 189(b) and
189(d).
49 CAA section 189(d), 40 CFR 51.1004(a)(3), 40
CFR 51.1010(c).
50 81 FR 58010, 58098.
51 40 CFR 51.1003(c)(1).
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nonattainment plan SIP submissions for
the area as RACM/RACT, BACM/BACT,
and most stringent measures (MSM) (if
applicable)) 52 that provide for
attainment of the NAAQS as
expeditiously as practicable and, from
the date of such submission until
attainment, demonstrate that the plan
will at a minimum achieve an annual
five percent reduction in emissions of
direct PM2.5 or any PM2.5 plan
precursor;
4. A demonstration (including air
quality modeling) that the plan provides
for attainment of the NAAQS at issue as
expeditiously as practicable;
5. Plan provisions that require RFP;
6. Quantitative milestones that the
state is to meet every three years until
the area is redesignated attainment and
that demonstrate RFP toward attainment
by the applicable date;
7. Contingency measures to be
implemented if the state fails to meet
any requirement concerning RFP or
quantitative milestones or to attain the
NAAQS at issue by the applicable
attainment date; and
8. Provisions to assure that control
requirements applicable to major
stationary sources of PM2.5, also apply to
major stationary sources of PM2.5
precursors, except where the state
demonstrates to the EPA’s satisfaction
that such sources do not contribute
significantly to PM2.5 levels that exceed
the NAAQS at issue in the area.53
A state’s section 189(d) plan
submission must demonstrate
attainment as expeditiously as
practicable, and no later than five years
from the date of the EPA’s
determination that the area failed to
attain, consistent with sections 179(d)(3)
and 172(a)(2) of the CAA.54
A state with a Serious PM2.5
nonattainment area that fails to attain
the NAAQS by the applicable Serious
area attainment date must also address
any statutory requirements applicable to
Moderate and Serious nonattainment
area plans under CAA sections 172 and
189 of the CAA to the extent that those
requirements have not already been
met.55 Because the EPA has not
previously approved a SIP submission
52 MSM is applicable if the EPA has previously
granted an extension of the attainment date under
CAA section 188(e) for the nonattainment area and
NAAQS at issue.
53 As discussed in section IV.H, California
submitted nonattainment NSR SIP revisions to
address the subpart 4 requirements for the San
Joaquin Valley Serious PM2.5 nonattainment area on
November 20, 2019. We are not proposing any
action on this submission at this time. We will act
on this submission through a separate rulemaking,
as appropriate.
54 81 FR 84481, 84482.
55 81 FR 58010, 58098.
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for the San Joaquin Valley as meeting
the subpart 4 RACM Moderate area
planning requirements under CAA
section 189 for the 1997 24-hour PM2.5
NAAQS, the EPA is evaluating relevant
portions of the SJV PM2.5 Plan for
compliance with this requirement. In
addition, as discussed above, the EPA
has not previously approved a SIP
submission for the San Joaquin Valley
as meeting the Serious area planning
requirements under CAA section
189(b)(1) for the 1997 24-hour PM2.5
NAAQS. Some Serious area planning
requirements operate on a timeline that
is based on the outermost statutory
Serious area attainment date of the end
of the tenth calendar year following the
area’s designation to nonattainment.
Because section 189(d) requires a state
to address any applicable Serious area
requirements that the state has not
already met in the area, and the section
189(d) obligations do not come into
effect until an area has failed to attain
the NAAQS by the Serious area
attainment date, the EPA proposes that
it should evaluate any previously unmet
Serious area planning obligations based
on the current, applicable attainment
date appropriate under section 189(d),
and not the original Serious area
attainment date.
The EPA provided its preliminary
views on the CAA’s requirements for
particulate matter plans under part D,
title I of the Act in the following
guidance documents: (1) ‘‘State
Implementation Plans; General
Preamble for the Implementation of
Title I of the Clean Air Act Amendments
of 1990’’ (‘‘General Preamble’’); 56 (2)
‘‘State Implementation Plans; General
Preamble for the Implementation of
Title I of the Clean Air Act Amendments
of 1990; Supplemental’’ (‘‘General
Preamble Supplement’’); 57 and (3)
‘‘State Implementation Plans for Serious
PM–10 Nonattainment Areas, and
Attainment Date Waivers for PM–10
Nonattainment Areas Generally;
Addendum to the General Preamble for
the Implementation of Title I of the
Clean Air Act Amendments of 1990’’
(‘‘General Preamble Addendum’’).58
More recently, in an August 24, 2016
final rule entitled, ‘‘Fine Particulate
Matter National Ambient Air Quality
Standards: State Implementation Plan
Requirements’’ (‘‘PM2.5 SIP
Requirements Rule’’), the EPA
established regulatory requirements and
provided further interpretive guidance
on the statutory SIP requirements that
apply to areas designated nonattainment
56 57
FR 13498 (April 16, 1992).
FR 18070 (April 28, 1992).
58 59 FR 41998 (August 16, 1994).
57 57
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for the PM2.5 NAAQS.59 We discuss
these regulatory requirements and
interpretations of the Act as appropriate
in our evaluation of the SJV PM2.5 Plan
that follows.
IV. Review of the San Joaquin Valley
PM2.5 Plan for the 1997 24-Hour PM2.5
NAAQS
The EPA is evaluating the SJV PM2.5
Plan against the Serious area
requirements for the 1997 24-hour PM2.5
NAAQS and the section 189(d)
requirements for the 1997 24-hour PM2.5
NAAQS, as laid out in section III of this
proposal. Many requirements for both a
Serious area plan and a section 189(d)
plan are structured around the relevant
statutory attainment date. The latest
statutory Serious area attainment date
for the San Joaquin Valley area was
December 31, 2015.60 On November 23,
2016, the EPA determined that the area
failed to attain by the Serious area
attainment date.
For the purposes of the section 189(d)
requirements, the attainment date is the
date by which a state can attain the
NAAQS as expeditiously as practicable,
but no later than five years from the
publication date of the final
determination of failure to attain.61 As
discussed in section IV.D, the SJV PM2.5
Plan projected that attainment could be
achieved in fewer than five years, i.e.,
by December 31, 2020.
When the State submitted the SJV
PM2.5 Plan in 2019, the State withdrew
its previous Serious area plan that it had
developed to meet the December 31,
2015 Serious area attainment date.
Because the State submitted the SJV
PM2.5 Plan after the EPA’s finding that
the area had failed to attain by the
applicable Serious area attainment date,
the State could not demonstrate in the
SJV PM2.5 Plan that the area would
attain by the Serious area attainment
date, nor could it address other
requirements based on this attainment
date, such as RFP and quantitative
milestones, because many of the
relevant dates had already passed. As
described in section III of this
59 81
FR 58010.
discussed in section I.B, California
submitted its Serious area plan for the 1997 24-hour
PM2.5 NAAQS in two submissions dated June 25,
2015 and August 13, 2015, including a request
under section 188(e) to extend the attainment date
for the 1997 24-hour PM2.5 NAAQS by three years
(to December 31, 2018). On October 6, 2016, the
EPA denied the request for an extension, but did
not finalize action on the Serious area plan
submissions. Accordingly, the Serious area
attainment date remained unchanged: As
expeditiously as practicable but no later than
December 31, 2015.
61 CAA section 179(d)(3); 81 FR 84481, 84482.
The determination of failure to attain published on
November 23, 2016.
60 As
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document, in a section 189(d) plan, a
state must address any statutory
requirements applicable to Moderate
and Serious nonattainment area plans to
the extent that it has not already met
those requirements, but the EPA
believes that it should base this
evaluation on the current applicable
attainment date under section 189(d).
For example, it would be illogical to
require a state to submit a Serious area
modeled attainment demonstration that
provided for attainment by December
31, 2015, after the EPA has already
determined based on monitoring data
that the state failed to attain by such
date.
For the purposes of our evaluation of
the Serious area plan requirements,
although the State is required to submit
a Serious area plan, and it must
structure such a plan based on the
Serious area attainment date, it would
serve no purpose to evaluate the SJV
PM2.5 Plan against the now-passed
Serious area attainment date by which
the area has already failed to attain. For
example, RFP and quantitative
milestones normally are dependent
upon the attainment date. Accordingly,
because the State must still meet all
Serious area plan requirements, even if
doing so later in conjunction with the
section 189(d) plan and its later
attainment date, we will evaluate the
State’s compliance with the Serious area
plan requirements in light of the later
section 189(d) attainment date, as
appropriate. Where the State in the SJV
PM2.5 Plan applies the section 189(d)
attainment date to a Serious area
requirement, we will note the statutory
Serious area timeline and accept the
submission in fulfillment of the State’s
Serious area plan obligation, but
evaluate the submission in light of the
section 189(d) attainment date.
A. Emissions Inventories
1. Statutory and Regulatory
Requirements
CAA section 172(c)(3) requires that
each SIP include a comprehensive,
accurate, current inventory of actual
emissions from all sources of the
relevant pollutant or pollutants in the
nonattainment area. The EPA discussed
the emissions inventory requirements
that apply to PM2.5 nonattainment areas
in the PM2.5 SIP Requirements Rule and
codified these requirements in 40 CFR
51.1008.62 The EPA has also issued
guidance concerning emissions
62 Id.
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inventories for PM2.5 nonattainment
areas.63
The base year emissions inventory for
a Serious area attainment plan or a CAA
section 189(d) plan must provide a
state’s best estimate of actual emissions
from all sources of the relevant
pollutants in the area, i.e., all emissions
that contribute to the formation of a
particular NAAQS pollutant. For the
PM2.5 NAAQS, the base year inventory
must include direct PM2.5 emissions,
separately reported filterable and
condensable PM2.5 emissions,64 and
emissions of all chemical precursors to
the formation of secondary PM2.5, i.e.,
nitrogen oxides (NOX), sulfur dioxide
(SO2), volatile organic compounds
(VOC), and ammonia.65
The emissions inventory base year for
a Serious area attainment plan must be
one of the three years for which
monitoring data were used to reclassify
the area to Serious, or another
technically appropriate year justified by
the state in its Serious area SIP
submission.66 The emissions inventory
base year for a Serious PM2.5
nonattainment area subject to CAA
section 189(d) must be one of the three
years for which the EPA used monitored
data to determine that the area failed to
attain the PM2.5 NAAQS by the
applicable Serious area attainment date,
or another technically appropriate year
justified by the state in its Serious area
SIP submission.67
A state’s SIP submission must include
documentation explaining how it
calculated emissions data for the
inventory. In estimating mobile source
emissions, a state should use the latest
emissions models and planning
assumptions available at the time the
SIP is developed. The latest EPAapproved version of California’s mobile
source emission factor model for
estimating tailpipe, brake, and tire wear
emissions from on-road mobile sources
that was available during the State’s and
District’s development of the SJV PM2.5
Plan was EMFAC2014.68 Following
63 ‘‘Emissions Inventory Guidance for
Implementation of Ozone and Particulate Matter
National Ambient Air Quality Standards (NAAQS)
and Regional Haze Regulations,’’ U.S. EPA, May
2017 (‘‘Emissions Inventory Guidance’’), available
at https://www.epa.gov/air-emissions-inventories/
air-emissions-inventory-guidance-implementationozone-and-particulate.
64 The Emissions Inventory Guidance identifies
the types of sources for which the EPA expects
states to provide condensable PM emissions
inventories. Emissions Inventory Guidance, section
4.2.1 (‘‘Condensable PM Emissions’’), 63–65.
65 40 CFR 51.1008(b)(1) and (c)(1).
66 40 CFR 51.1008(b)(1).
67 40 CFR 51.1008(c)(1).
68 80 FR 77337 (December 14, 2015). EMFAC is
short for EMission FACtor. The EPA announced the
availability of the EMFAC2014 model, effective on
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CARB’s submission of the Plan, the EPA
approved EMFAC2017, the latest
revision to this mobile source emissions
model. States are also required to use
the EPA’s ‘‘Compilation of Air Pollutant
Emission Factors’’ (‘‘AP–42’’) road dust
method for calculating re-entrained road
dust emissions from paved roads.69 70
In addition to the base year inventory
submitted to meet the requirements of
CAA section 172(c)(3), the state must
also submit a projected attainment year
inventory and emissions projections for
each RFP milestone year.71 These future
emissions projections are necessary
components of the attainment
demonstrations required under CAA
sections 189(b)(1) and 189(d) and the
demonstration of RFP required under
section 172(c)(2).72 Emissions
projections for future years (referred to
in the Plan as ‘‘forecasted inventories’’)
should account for, among other things,
the ongoing effects of economic growth
and adopted emissions control
requirements. The state’s SIP
submission should include
documentation to explain how the state
calculated the emissions projections.
Where a state chooses to allow new
major stationary sources or major
modifications to use emissions
reduction credits (ERCs) that were
generated through shutdown or
curtailed emissions units occuring
before the base year of an attainment
plan, the projected emissions inventory
used to develop the attainment
demonstration must explicitly include
the date of publication in the Federal Register, for
use in state implementation plan development and
transportation conformity in California. Upon that
action, EMFAC2014 was required to be used for all
new regional emissions analyses and CO, PM10, and
PM2.5 hot-spot analyses that were started on or after
December 14, 2017, which was the end of the grace
period for using the prior mobile source emissions
model, EMFAC2011.
69 The EPA released an update to AP–42 in
January 2011 that revised the equation for
estimating paved road dust emissions based on an
updated data regression that included new
emissions tests results. 76 FR 6328 (February 4,
2011). CARB used the revised 2011 AP–42
methodology in developing on-road mobile source
emissions; see https://www.arb.ca.gov/ei/areasrc/
fullpdf/full7-9_2016.pdf.
70 AP–42 has been published since 1972 as the
primary source of the EPA’s emission factor
information and is available at https://
www.epa.gov/air-emissions-factors-andquantification/ap-42-compilation-air-emissionsfactors. It contains emission factors and process
information for more than 200 air pollution source
categories. A source category is a specific industry
sector or group of similar emitting sources. The
emission factors have been developed and compiled
from source test data, material balance studies, and
engineering estimates.
71 40 CFR 51.1008 and 51.1012. See also
Emissions Inventory Guidance, section 3 (‘‘SIP
Inventory Requirements and Recommendations’’).
72 40 CFR 51.1004, 51.1008, 51.1011, and
51.1012.
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the emissions from such previously
shutdown or curtailed emissions
units.73
2. Summary of the State’s Submission
The State included summaries of the
planning emissions inventories for
direct PM2.5 and PM2.5 precursors (NOX,
SOX,74 VOC,75 and ammonia) and the
documentation for the inventories for
the San Joaquin Valley PM2.5
nonattainment area in Appendix B
(‘‘Emissions Inventory’’) and Appendix
I (‘‘New Source Review and Emission
Reduction Credits’’) of the 2018 PM2.5
Plan.
CARB and District staff worked
together to develop the emissions
inventories for the San Joaquin Valley
PM2.5 nonattainment area. The District
worked with operators of the stationary
facilities in the nonattainment area to
develop the stationary source emissions
estimates. The responsibility for
developing emissions estimates for area
sources such as agricultural burning and
paved road dust was shared by the
District and CARB. CARB staff
developed the emissions inventories for
both on-road and non-road mobile
sources.76
The Plan includes winter (24-hour)
average and annual average daily
emissions inventories for the 2013 base
year, which CARB derived from the
2012 emissions inventory, and
estimated emissions for forecasted years
from 2017 through 2028 for the
attainment and RFP demonstrations for
the 1997, 2006, and 2012 PM2.5
NAAQS.77 In this proposal, we are
proposing action on those winter
average and annual average emissions
inventories necessary to support the
Serious area and CAA section 189(d)
nonattainment plans for the 1997 2473 40
CFR 51.165(a)(3)(ii)(C)(1).
SJV PM2.5 Plan generally uses ‘‘sulfur
oxides’’ or ‘‘SOX’’ in reference to SO2 as a precursor
to the formation of PM2.5. We use SOX and SO2
interchangeably throughout this document.
75 The SJV PM
2.5 Plan generally uses ‘‘reactive
organic gasses’’ or ‘‘ROG’’ in reference to VOC as
a precursor to the formation of PM2.5. We use ROG
and VOC interchangeably throughout this
document.
76 The EPA regulations refer to ‘‘non-road’’
vehicles and engines whereas CARB regulations
refer to ‘‘Other Mobile Sources’’ or ‘‘off-road’’
vehicles and engines. These terms refer to the same
types of vehicles and engines. We refer herein to
such vehicles and engines as ‘‘non-road’’ sources.
77 2018 PM
2.5 Plan, Appendix B, B–18 to B–19.
The winter average daily planning inventory
corresponds to the months of November through
April, when daily, ambient PM2.5 concentrations are
typically highest. The base year inventory is from
the California Emissions Inventory Development
and Reporting System and future year inventories
were estimated using the California Emission
Projection Analysis Model (CEPAM), 2016 SIP
Baseline Emission Projections, version 1.05.
74 The
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hour PM2.5 NAAQS, i.e., the 2013 base
year inventory, forecasted inventories
for the RFP milestone years of 2017,
2020 (attainment year), and 2023 (postattainment milestone year), and
additional forecasted emissions
inventories for 2018 and 2019 to
support the five percent annual
emissions reduction demonstration as
required by CAA section 189(d). Each
inventory includes emissions from
stationary, area, on-road, and non-road
sources.
CARB developed the base year
inventories for stationary sources using
actual emissions reports from facility
operators. The State developed the base
year emissions inventory for area
sources using the most recent models
and methodologies available at the time
the State was developing the Plan.78 The
Plan also includes background,
methodology, and inventories of
condensable and filterable PM2.5
emissions from stationary point and
non-point combustion sources that are
expected to generate condensable
PM2.5.79 CARB used EMFAC2014 to
estimate on-road motor vehicle
emissions based on transportation
activity data from the 2014 Regional
Transportation Plan (2014 RTP) adopted
by the transportation planning agencies
in the San Joaquin Valley.80 Reentrained paved road dust emissions
were calculated using a CARB
methodology consistent with the EPA’s
AP–42 road dust methodology.81
CARB developed the emissions
forecasts by applying growth and
control profiles to the base year
inventory. CARB’s mobile source
emissions projections take into account
predicted activity rates and vehicle fleet
turnover by vehicle model year and
adopted controls.82 In addition, the Plan
states that the District is providing for
use of pre-base year ERCs as offsets by
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accounting for such ERCs in the
projected 2025 emissions inventory.83
The 2018 PM2.5 Plan identifies growth
factors, control factors, and estimated
offset use between 2013 and 2025 for
direct PM2.5, NOX, SOX, and VOC
emissions by source category and lists
all pre-base year ERCs issued by the
District for PM10, NOX, SOX, and VOC
emissions, by facility.84
Table 1 provides a summary of the
winter (24-hour) average inventories in
tons per day (tpd) of direct PM2.5 and
PM2.5 precursors for the 2013 base year.
Table 2 provides a summary of annual
average inventories of direct PM2.5 and
PM2.5 precursors for the 2013 base year.
These annual average inventories
provide the basis for the control
measure analysis and the RFP and
attainment demonstrations in the SJV
PM2.5 Plan.
TABLE 1—SAN JOAQUIN VALLEY WINTER AVERAGE EMISSIONS INVENTORY FOR DIRECT PM2.5 AND PM2.5 PRECURSORS
FOR THE 2013 BASE YEAR (tpd)
Category
Direct PM2.5
NOX
SOX
VOC
Ammonia
Stationary Sources ...............................................................
Area Sources .......................................................................
On-Road Mobile Sources ....................................................
Non-Road Mobile Sources ...................................................
8.5
41.4
6.4
4.4
35.0
11.5
188.7
65.3
6.9
0.5
0.6
0.3
86.6
156.8
51.1
27.4
13.9
291.5
4.4
0.0
Totals a ..........................................................................
60.8
300.5
8.4
321.9
309.8
Source: 2018 PM2.5 Plan, Appendix B, tables B–1 to B–5.
a Totals reflect disaggregated emissions and may not add exactly as shown here due to rounding.
TABLE 2—SAN JOAQUIN VALLEY ANNUAL AVERAGE EMISSIONS INVENTORY FOR DIRECT PM2.5 AND PM2.5 PRECURSORS
FOR THE 2013 BASE YEAR (tpd)
Category
Direct PM2.5
NOX
SOX
VOC
Ammonia
Stationary Sources ...............................................................
Area Sources .......................................................................
On-Road Mobile Sources ....................................................
Non-Road Mobile Sources ...................................................
8.8
41.5
6.4
5.8
38.6
8.1
183.1
87.4
7.2
0.3
0.6
0.3
87.1
153.4
49.8
33.8
13.9
310.9
4.4
0.0
Totals a ..........................................................................
62.5
317.2
8.5
324.1
329.2
Source: 2018 PM2.5 Plan, Appendix B, tables B–1 to B–5.
a Totals reflect disaggregated emissions and may not add exactly as shown here due to rounding.
3. The EPA’s Review of the State’s
Submission
We have reviewed the emissions
inventories in the SJV PM2.5 Plan that
pertain to the 1997 24-hour PM2.5
NAAQS and the emissions inventory
estimation methodologies used by
California for consistency with CAA
requirements and the EPA’s guidance.
We find that the inventories are based
on the most current and accurate
information available to the State and
78 2018 PM
2.5 Plan, Appendix B, section B.2
(‘‘Emissions Inventory Summary and
Methodology’’).
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District at the time they were
developing the Plan and inventories,
including the latest version of
California’s mobile source emissions
model that had been approved by the
EPA at the time, EMFAC2014. The
inventories comprehensively address all
source categories in the San Joaquin
Valley PM2.5 nonattainment area and are
consistent with the EPA’s inventory
guidance.
at B–42 to B–44.
at B–37.
81 Id. at B–28.
In accordance with 40 CFR
51.1008(b)(1), the 2013 base year is one
of the three years of monitored data
with which the EPA reclassified the San
Joaquin Valley area to Serious.
Furthermore, in accordance with 40
CFR 51.1008(c)(1), the 2013 base year is
one of the three years of monitored data
with which the EPA determined that the
San Joaquin Valley area failed to attain
the PM2.5 NAAQS by the applicable
Serious area attainment date for the
79 Id.
82 Id.
80 Id.
83 2018
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PM2.5 Plan, Appendix I, I–1 to I–5.
84 Id. at tables I–1 to I–5.
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1997 24-hour PM2.5 NAAQS.85 The 2013
base year emissions inventories
represent actual annual average
emissions of all sources within the
nonattainment area, direct PM2.5 and
PM2.5 precursors are included in the
inventories, and filterable and
condensable direct PM2.5 emissions are
identified separately.
With respect to future year emissions
projections, we have reviewed the
growth and control factors and find
them acceptable and thus conclude that
the future baseline emissions
projections, which reflect ongoing
emissions reductions from existing (i.e.,
‘‘baseline’’) control measures as
discussed in section IV.C.2.a, in the SJV
PM2.5 Plan reflect appropriate
calculation methods and the latest
planning assumptions. Also, as a
general matter, the EPA will approve a
SIP submission that takes emissions
reduction credit for a control measure
only where the EPA has approved the
measure as part of the SIP. Thus, for
example, to take credit for the emissions
reductions from newly adopted or
amended District rules for stationary
sources, the related rules must be
approved by the EPA into the SIP. Table
1 of the EPA’s ‘‘Technical Support
Document, San Joaquin Valley PM2.5
Plan for the 1997 24-hour PM2.5
NAAQS,’’ August 2021 (‘‘EPA’s 1997
24-hour PM2.5 TSD’’) shows District
rules with post-2013 compliance dates
that are reflected in the future year
baseline inventories, along with
information on the EPA’s approval of
these rules, and shows that stationary
source emissions reductions assumed by
the SJV PM2.5 Plan for future years are
supported by rules approved as part of
the California SIP for the San Joaquin
Valley. With respect to mobile sources,
the EPA has taken action in recent years
to approve CARB mobile source
regulations into the state-wide portion
of the California SIP. We therefore find
that the future year baseline projections
in the SJV PM2.5 Plan are properly
supported by SIP-approved stationary
and mobile source measures.86
85 81
FR 84481, 84482.
baseline emissions projections in the 2018
PM2.5 Plan assume implementation of CARB’s Zero
Emissions Vehicle (ZEV) sales mandate and
greenhouse gas (GHG) standards. On September 27,
2019, the U.S. Department of Transportation and
the EPA (the Agencies) issued a notice of final
rulemaking for the Safer Affordable Fuel-Efficient
(SAFE) Vehicles Rule Part One: One National
Program (SAFE I) that, among other things,
withdrew the EPA’s 2013 waiver of preemption for
the ZEV sales mandate and vehicle GHG standards.
84 FR 51310. See also proposed SAFE rule at 83 FR
42986 (August 24, 2018). In response to SAFE I,
CARB developed EMFAC off-model adjustment
factors to account for anticipated changes in onroad emissions. On March 12, 2020, the EPA
86 The
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For these reasons, we are proposing to
approve the 2013 base year emissions
inventories in the SJV PM2.5 Plan for the
1997 24-hour PM2.5 NAAQS as meeting
the requirements of CAA section
172(c)(3) and 40 CFR 51.1008 for
purposes of both the Serious area and
the CAA section 189(d) attainment
plans. We are also proposing to find that
the forecasted inventories in the Plan for
the years 2017, 2018, 2019, 2020, and
2023 provide an adequate basis for the
BACM, RFP, and the modeled
attainment demonstration analyses in
the SJV PM2.5 Plan.
B. PM2.5 Precursors
1. Statutory and Regulatory
Requirements
The composition of PM2.5 is complex
and highly variable due in part to the
large contribution of secondary PM2.5 to
total fine particle mass in most
locations, and to the complexity of
secondary particle formation processes.
A large number of possible chemical
reactions, often non-linear in nature,
can convert gaseous NOX, SO2, VOC,
and ammonia to PM2.5, making them
precursors to PM2.5.87 Formation of
secondary PM2.5 may also depend on
atmospheric conditions, including solar
radiation, temperature, and relative
humidity, and the interactions of
precursors with preexisting particles
and with cloud or fog droplets.88
Under subpart 4 of part D, title I of the
CAA and the PM2.5 SIP Requirements
Rule, each state containing a PM2.5
nonattainment area must evaluate all
PM2.5 precursors for regulation unless,
for any given PM2.5 precursor, the state
demonstrates to the Administrator’s
satisfaction that such precursor does not
contribute significantly to PM2.5 levels
informed CARB that the EPA considers these
adjustment factors to be acceptable for future use.
See letter dated March 12, 2020 from Elizabeth J.
Adams, EPA Region IX, to Steven Cliff, CARB. On
April 30, 2020 (85 FR 24174), the Agencies issued
a notice of final rulemaking titled: The Safer
Affordable Fuel-Efficient (SAFE) Vehicles Rule for
Model Years 2021–2026 Passenger Cars and Light
Trucks (SAFE II), establishing the federal fuel
economy and GHG vehicle emissions standards
based on the August 2018 SAFE proposal. The
effect of both SAFE final rules (SAFE I and SAFE
II) on the on-road vehicle mix in the San Joaquin
Valley nonattainment area and on the resulting
vehicular emissions is expected to be minimal
during the timeframe addressed in this SIP revision.
Therefore, we anticipate the SAFE final rules would
not materially change the attainment, RFP, or five
percent reductions demonstrations for the 1997 24hour PM2.5 NAAQS in the SJV PM2.5 Plan.
87 ‘‘Air Quality Criteria for Particulate Matter’’
(EPA/600/P–99/002aF), EPA, October 2004, Chapter
3.
88 ‘‘Regulatory Impact Analysis for the Final
Revisions to the National Ambient Air Quality
Standards for Particulate Matter’’ (EPA/452/R–12–
005), EPA, December 2012), 2–1.
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that exceed the NAAQS in the
nonattainment area.89 The provisions of
subpart 4 do not define the term
‘‘precursor’’ for purposes of PM2.5, nor
do they explicitly require the control of
any specifically identified PM2.5
precursor. The statutory definition of
‘‘air pollutant,’’ however, provides that
the term ‘‘includes any precursors to the
formation of any air pollutant, to the
extent the Administrator has identified
such precursor or precursors for the
particular purpose for which the term
‘air pollutant’ is used.’’ 90 The EPA has
identified NOX, SO2, VOC, and
ammonia as precursors to the formation
of PM2.5.91 Accordingly, the attainment
plan requirements of subpart 4 apply to
emissions of all four precursor
pollutants and direct PM2.5 from all
types of stationary, area, and mobile
sources, except as otherwise provided in
the Act (e.g., CAA section 189(e)).
Section 189(e) of the Act requires that
the control requirements for major
stationary sources of direct PM10 also
apply to major stationary sources of
PM10 precursors, except where the
Administrator determines that such
sources do not contribute significantly
to PM10 levels that exceed the standard
in the area. Section 189(e) contains the
only express exception to the control
requirements under subpart 4 (e.g.,
requirements for RACM and RACT,
BACM and BACT, MSM, and new
source review (NSR)). Although section
189(e) explicitly addresses only major
stationary sources, the EPA interprets
the Act as authorizing it also to
determine, under appropriate
circumstances, that regulation of
specific PM2.5 precursors from other
source categories in a given
nonattainment area is not necessary.92
For example, under the EPA’s
longstanding interpretation of the
control requirements that apply to
stationary, area, and mobile sources of
PM10 precursors in the nonattainment
area under CAA section 172(c)(1) and
subpart 4,93 a state may demonstrate in
a SIP submission that control of a
certain precursor pollutant is not
necessary because it does not contribute
significantly to ambient PM10 levels in
the nonattainment area and is not
needed for attainment.94
Under the PM2.5 SIP Requirements
Rule, a state may elect to submit to the
89 81
FR 58010, 58017–58020.
section 302(g).
91 81 FR 58010, 58015.
92 Id. at 58018–58019.
93 General Preamble, 13539–13542.
94 Courts have upheld this approach to the
requirements of subpart 4 for PM10. See, e.g., Assoc.
of Irritated Residents v. EPA, et al., 423 F.3d 989
(9th Cir. 2005).
90 CAA
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EPA a ‘‘comprehensive precursor
demonstration’’ for a specific
nonattainment area to show that
emissions of a particular precursor from
all existing sources located in the
nonattainment area do not contribute
significantly to PM2.5 levels that exceed
the standard in the area.95 If the EPA
determines that the contribution of the
precursor to PM2.5 levels in the area is
not significant and approves the
demonstration, then the state is not
required to control emissions of the
relevant precursor from sources in the
attainment plan.96
In addition, in May 2019, the EPA
issued the ‘‘Fine Particulate Matter
(PM2.5) Precursor Demonstration
Guidance’’ (‘‘PM2.5 Precursor
Guidance’’),97 which provides
recommendations to states for analyzing
nonattainment area PM2.5 emissions and
developing such optional precursor
demonstrations, consistent with the
PM2.5 SIP Requirements Rule. The PM2.5
Precursor Guidance builds upon the
draft version of the guidance, released
on November 17, 2016 (‘‘Draft PM2.5
Precursor Guidance’’), which CARB
referenced in developing its precursor
demonstration in the SJV PM2.5 Plan.98
The EPA’s recommendations in the
PM2.5 Precursor Guidance are generally
consistent with those in the Draft PM2.5
Precursor Guidance, with some
exceptions, including that the EPA’s
recommended contribution threshold
for the 24-hour PM2.5 NAAQS changed
from 1.3 mg/m3 in the draft guidance to
1.5 mg/m3 in the final guidance.99
We are evaluating the 1997 24-hour
PM2.5 NAAQS portion of the SJV PM2.5
Plan in accordance with the
presumption embodied within subpart
4, that states address all PM2.5
precursors in the evaluation of potential
control measures unless the state
adequately demonstrates that emissions
of a particular precursor or precursors
95 40
CFR 51.1006(a)(1).
96 Id.
97 ‘‘PM
2.5 Precursor Demonstration Guidance,’’
EPA–454/R–19–004, May 2019, including
memorandum dated May 30, 2019 from Scott
Mathias, Acting Director, Air Quality Policy
Division and Richard Wayland, Director, Air
Quality Assessment Division, Office of Air Quality
Planning and Standards (OAQPS), EPA to Regional
Air Division Directors, Regions 1–10, EPA.
98 ‘‘PM
2.5 Precursor Demonstration Guidance,
Draft for Public Review and Comments,’’ EPA–454/
P–16–001, November 17, 2016, including
memorandum dated November 17, 2016 from
Stephen D. Page, Director, OAQPS, EPA to Regional
Air Division Directors, Regions 1–10, EPA.
99 For the 24-hour PM
2.5 NAAQS, the EPA
generally expects that a precursor demonstration
showing that the air quality impact of a given
precursor at all relevant locations does not exceed
a contribution threshold of 1.5 mg/m3 will be
adequate to exempt sources of that precursor from
control requirements. PM2.5 Precursor Guidance, 17.
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do not contribute significantly to
ambient PM2.5 levels that exceed the
PM2.5 NAAQS in the nonattainment area
and are not necessary for attainment. In
reviewing any determination by a state
to exclude a PM2.5 precursor from the
required evaluation of potential control
measures, we consider both the
magnitude of the precursor’s
contribution to ambient PM2.5
concentrations in the nonattainment
area and the sensitivity of ambient PM2.5
concentrations in the area to reductions
in emissions of that precursor.
2. Summary of the State’s Submission
The State presents a brief summary of
its PM2.5 precursor analysis in Chapter
5 of the 2018 PM2.5 Plan and the full
precursor demonstration in Appendix G
(‘‘Precursor Demonstration’’) of the 2018
PM2.5 Plan.100 CARB presents additional
modeling results in Appendix K
(‘‘Modeling Attainment
Demonstration’’), section 5.6 (‘‘PM2.5
Precursor Sensitivity Analysis’’). CARB
also provided clarifying information on
its precursor assessment, including an
Attachment A to its letter transmitting
the 2018 PM2.5 Plan to the EPA 101 and
further clarifications in five email
transmittals.102 The CARB Staff Report
contains additional discussion of the
role of ammonia in the formation of
ammonium nitrate and the role of VOC
in the formation of ammonium nitrate
and secondary organic aerosol.103
100 A copy of the contents of Appendix G appears
in the CARB Staff Report, Appendix C4 (‘‘Precursor
Demonstrations for Ammonia, SOX, and ROG’’).
101 Letter dated May 9, 2019, from Richard Corey,
Executive Officer, CARB, to Michael Stoker,
Regional Administrator, EPA Region 9, Attachment
A (‘‘Clarifying information for the San Joaquin
Valley 2018 Plan regarding model sensitivity
related to ammonia and ammonia controls’’).
102 Email dated June 20, 2019, from Jeremy Avise,
CARB, to Scott Bohning, EPA Region IX, Subject:
‘‘RE: SJV model disbenefit from SOX reduction,’’
with attachment (‘‘CARB’s June 2019 Precursor
Clarification’’); email dated September 19, 2019,
from Jeremy Avise, CARB, to Scott Bohning, EPA
Region IX, Subject: ‘‘FW: SJV species responses,’’
with attachments (‘‘CARB’s September 2019
Precursor Clarification’’); email dated October 18,
2019, from Laura Carr, CARB, to Scott Bohning,
Jeanhee Hong, and Rory Mays, EPA Region IX,
Subject: ‘‘Clarifying information on ammonia,’’ with
attachment ‘‘Clarifying Information on Ammonia’’
(‘‘CARB’s October 2019 Precursor Clarification’’);
email dated April 19, 2021, from Laura Carr, CARB,
to Rory Mays, EPA Region IX, Subject: ‘‘Ammonia
update,’’ with attachment ‘‘Update on Ammonia in
the San Joaquin Valley’’ (‘‘CARB’s April 19, 2021
Precursor Clarification’’); and email dated April 26,
2021, from Laura Carr, CARB, to Scott Bohning,
EPA Region IX, Subject: ‘‘RE: Ammonia update,’’
with attachment ‘‘Ammonia in San Joaquin Valley’’
(‘‘CARB’s April 26, 2021 Precursor Clarification’’).
103 CARB Staff Report, Appendix C, 9–16. The
CARB Staff Report, Appendix C4 (‘‘Precursor
Demonstrations for Ammonia, SOX, and ROG’’) is
very similar to the contents of Appendix G of the
2018 PM2.5 Plan.
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The 2018 PM2.5 Plan provides both
concentration-based and sensitivitybased analyses of precursor
contributions to ambient PM2.5
concentrations in the San Joaquin
Valley. The State supplemented the
sensitivity analysis, particularly for
ammonia, with additional information,
including factors identified in the PM2.5
Precursor Guidance, such as emissions
trends, the appropriateness of future
year versus base year sensitivity,
available emissions controls, and the
severity of nonattainment.104 These
analyses led CARB to conclude that
direct PM2.5 and NOX emissions
contribute significantly to ambient
PM2.5 levels that exceed the PM2.5
NAAQS in the San Joaquin Valley while
ammonia, SOX, and VOC do not
contribute significantly to such
exceedances.105 We summarize the
State’s analysis and conclusions below.
For a more detailed summary of the
precursor demonstration in the Plan,
please refer to the EPA’s ‘‘Technical
Support Document, EPA Evaluation of
PM2.5 Precursor Demonstration, San
Joaquin Valley PM2.5 Plan for the 2006
PM2.5 NAAQS,’’ February 2020 (‘‘EPA’s
February 2020 Precursor TSD’’).
For direct PM2.5 and NOX, CARB
modeled the sensitivity of ambient
PM2.5 in the San Joaquin Valley to a 30
percent reduction in anthropogenic
emissions of each pollutant in 2013,
2020, and 2024.106 The State concluded
that direct PM2.5 and NOX emissions
reductions will continue to have a
significant impact on 24-hour PM2.5
design values in the San Joaquin Valley,
with NOX reductions being particularly
important.107 Consistent with this
conclusion, the State focused the
control strategy and attainment
demonstration on these two pollutants,
104 PM
2.5 Precursor Guidance, 18–19
(consideration of additional information), 31
(available emissions controls), and 35–36
(appropriateness of future year versus base year
sensitivity).
105 Direct PM
2.5 emissions are considered a
primary source of ambient PM2.5 (i.e., no further
formation in the atmosphere is required), and
therefore is not considered a precursor pollutant
under subpart 4, which may differ from a more
generalized understanding of what contributes to
ambient PM2.5.
106 2018 PM
2.5 Plan, Chapter 5, 5–7 to 5–8. CARB
modeled the effects of both NOX reductions and
direct PM2.5 reductions but the direct PM2.5 results
were used only as a point of comparison, as direct
PM2.5 emissions must be regulated in all PM2.5
nonattainment areas.
107 Id. at 5–8; and 2018 PM
2.5 Plan, Appendix G,
2. CARB presents its sensitivity analysis for
emissions reductions in direct PM2.5 and NOX in the
Plan’s attainment demonstration appendix. 2018
PM2.5 Plan, Appendix K, Table 47 (annual average
design values) and Table 48 (24-hour average design
values).
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as described in section IV.C of this
preamble.
For ammonia, SOX, and VOC, CARB
assessed the 2015 annual average
concentration of each precursor in
ambient PM2.5 at Bakersfield, for which
the necessary speciated PM2.5 data are
available and where the highest PM2.5
design values have been recorded in
most years, and compared those
concentrations to the recommended
annual average contribution threshold
of 0.2 mg/m3 from the Draft PM2.5
Precursor Guidance, which was
available at the time the State developed
the SIP.108 The contributions of
ammonia, SOX, and VOC were 5.2 mg/
m3, 1.6 mg/m3, and 6.2 mg/m3,
respectively. Given that these levels are
well above the EPA’s 0.2 mg/m3
recommended contribution threshold,
the State proceeded with a sensitivitybased analysis.
CARB’s sensitivity-based analysis
used the same Community Multiscale
Air Quality (CMAQ) modeling platform
as that used for the Plan’s attainment
demonstration. The State modeled the
sensitivity of ambient PM2.5
concentration in the San Joaquin Valley
to 30 percent and 70 percent emissions
reductions in 2013, 2020, and 2024 for
each of ammonia, SOX, and VOC. The
State estimated baseline (2013, 2020,
and 2024) design values for PM2.5 using
relative response factors (RRFs) and
calculated the ammonia, SOX, and VOC
precursor contribution for a given year
and for each sensitivity scenario (30
percent and 70 percent emissions
reductions) as the difference between its
baseline design value and the design
value for each sensitivity scenario.109
We summarize the State’s sensitivitybased analysis and additional
information in the sections that follow
for ammonia, SOX, and VOC.
a. Ammonia
For ammonia, the State compared the
24-hour precursor contributions to 1.3
mg/m3, the recommended contribution
threshold in the Draft PM2.5 Precursor
108 2018 PM
2.5 Plan, Appendix G, 3. The Plan
does not present a concentration-based analysis for
the 24-hour average concentrations in the San
Joaquin Valley. Instead, CARB relied on the annual
average concentration-based analysis as an interim
step to the sensitivity-based analysis, for which
CARB assessed the sensitivity of both 24-hour
average and annual average ambient PM2.5
concentrations to precursor emissions reductions.
Separately, the Plan presents a graphical
representation of annual average ambient PM2.5
components (i.e., crustal particulate matter,
elemental carbon, organic matter, ammonium
sulfate, and ammonium nitrate) for 2011–2013 for
Bakersfield, Fresno, and Modesto. 2018 PM2.5 Plan,
Chapter 3, 3–3 to 3–4.
109 This procedure is the procedure recommended
by the EPA. PM2.5 Precursor Guidance, 37.
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Guidance. For a modeled 30 percent
ammonia emissions reduction, the
ambient PM2.5 responses in 2013 ranged
from 0.9 to 3.3 mg/m3 across 15
monitoring sites, with a majority of sites
above the 1.3 mg/m3 contribution
threshold (and also above the 1.5 mg/m3
contribution threshold in the final PM2.5
Precursor Guidance). PM2.5 responses in
2020 ranged from 0.5 to 1.9 mg/m3, with
four sites at or above the 1.3 mg/m3
contribution threshold, including one
site above the 1.5 mg/m3 contribution
threshold in the final PM2.5 Precursor
Guidance. In 2024, all modeled
responses were below both
recommended contribution thresholds.
For a modeled 70 percent ammonia
emissions reduction, the ambient PM2.5
responses in 2013 ranged from 3.5 to
12.4 mg/m3, with all monitoring sites
above the 1.3 mg/m3 threshold (and
above the 1.5 mg/m3 threshold), the
PM2.5 responses in 2020 ranged from 1.6
to 6.4 mg/m3, and the PM2.5 responses in
2024 ranged from 1.2 to 3.0 mg/m3, with
most sites above both recommended
thresholds. For further detail, please see
the EPA’s February 2020 Precursor TSD,
Table 2, and the 2018 PM2.5 Plan,
Appendix G, tables 2 through 7. In
summary, for a 30 percent ammonia
reduction, a majority of sites have PM2.5
responses above the contribution
threshold in the 2013 modeling,
decreasing to a single site above the
contribution threshold for 2020, and no
sites above the contribution threshold
for 2024. For a 70 percent reduction, all
sites are above the contribution
threshold in the 2013 and 2020
modeling, and a majority of sites are
above the contribution threshold in
2024.
The State based its ammonia
precursor determination on the
sensitivity analysis for the future years,
using a 30 percent ammonia emissions
reduction. These choices respectively
reflect its assessment of research studies
and the Plan’s projected emissions
reductions, and on its assessment of
available emissions controls. As
explained in the PM2.5 Precursor
Guidance, precursor responses may be
above the recommended contribution
threshold and yet not contribute
significantly to levels that exceed the
standard in the area. Therefore, as
recommended by the EPA, the State
considered additional information to
examine whether the identified PM2.5
responses constituted a significant
contribution to ambient PM2.5 in the San
Joaquin Valley. The additional
information included research studies,
emissions trends, and information to
support the State’s conclusion that a 30
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percent ammonia emissions reduction
represented a reasonable upper bound
on the ammonia emissions reductions to
model in estimating its contribution to
ambient PM2.5 levels. We summarize
this additional information below and
provide a more detailed evaluation in
the EPA’s February 2020 Precursor TSD.
The State describes previous research
that supports its finding that ammonium
nitrate PM2.5 formation is the San
Joaquin Valley is NOX-limited rather
than ammonia-limited.110 Essentially,
ammonia is so abundant in the San
Joaquin Valley that even with large
ammonia emissions reductions there
would still be enough ammonia to
combine with the available NOX to
readily form particulate ammonium
nitrate. Therefore, ammonia emissions
reductions would lead to only small
decreases in PM2.5 concentrations. In
contrast, because emissions of NOX are
less abundant in the San Joaquin Valley
(i.e., more limited relative to emissions
of ammonia after normalizing for their
differing molecular weights), the PM2.5
concentrations in the atmosphere are
more responsive to reductions in NOX
than to reductions of ammonia. Thus,
these analyses indicate that the area is
NOX-limited.
The State also points to the
conclusions of a study conducted by
Lurmann et al., based on ambient
measurements during the winter 2000–
2001 California Regional Particulate Air
Quality Study intensive field study.111
That study found that most areas of the
San Joaquin Valley were NOX-limited
with respect to ammonium nitrate
formation. Since that time, large
additional NOX emissions reductions
have occurred, which would increase
the degree to which ammonium nitrate
formation in the San Joaquin Valley is
NOX-limited. Based on more recent
aircraft-borne measurements during the
2013 DISCOVER–AQ campaign,112 the
State similarly concluded that
ammonium nitrate formation is NOXlimited based on the large amount of
‘‘excess ammonia,’’ which is defined as
the amount of measured ammonia left
over if all the nitrate and sulfate present
110 2018 PM
2.5 Plan, Appendix G, 9–10; CARB
Staff Report, Appendix C, 12–15; and Attachment
A to CARB’s May 9, 2019 submittal letter.
111 Frederick W. Lurmann, Steven G. Brown,
Michael C. McCarthy, and Paul T. Roberts,
‘‘Processes Influencing Secondary Aerosol
Formation in the San Joaquin Valley during
Winter,’’ Journal of the Air & Waste Management
Association, (2006), 56:12, 1679–1693, DOI:
10.1080/10473289.2006.10464573.
112 Deriving Information on Surface conditions
from COlumn and VERtically Resolved
Observations Relevant to Air Quality,’’ https://
www.nasa.gov/mission_pages/discover-aq/
index.html.
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were to combine with available
ammonia to form particulate.113 The
CARB Staff Report describes these
conclusions in more detail and lists
results from multiple other recent
studies with similar conclusions.114
Finally, in a supplemental submittal,
CARB described the results of two
analyses confirming the likely
underestimation of ammonia emissions
in the modeled emissions inventory
inputs.115 CARB compared CMAQ
model predictions of ammonia with the
2013 DISCOVER–AQ aircraft
measurements and found ammonia was
underpredicted, and noted that this
would result in the response to
ammonia reductions being
overpredicted. CARB also compared
2017 satellite measurements of
ammonia with CMAQ model
predictions and found that modeled
ammonia concentrations were half of
the magnitude of the satellite
observations at some locations, and the
modeled valley-wide average was about
25 percent less than observed. Because
the modeling performs well for the
various PM2.5 components, as well as for
ozone and NO2,116 the CARB finding of
CMAQ model underpredictions for
ammonia is consistent with an
underestimation of ammonia emissions
inventory input to the model.
Regarding emissions trends, the CARB
Staff Report presents an emissions
inventory-based argument on the
relative insensitivity of PM2.5 to
ammonia reductions.117 CARB
compared the size of the ammonia and
NOX emissions inventories in tons per
day, after normalizing for their differing
molecular weights, and found that
ammonia was roughly three times as
abundant as NOX in 2013 and is
projected to be about six times as
abundant in 2025, due to the continuing
decline in NOX emissions (while
ammonia emissions are generally
constant into the future).118 While the
State recognized that this is only a
‘‘first-level assessment,’’ it provides
additional support for the State’s
conclusion that NOX, and not ammonia,
is the limiting precursor for ammonium
nitrate formation, and that the
ammonium nitrate portion of ambient
PM2.5 would be expected to be relatively
insensitive to ammonia emissions
reductions. This is also consistent with
113 2018
PM2.5 Plan, Appendix G, Figure 2.
Staff Report, Appendix C, 12.
115 CARB’s April 26, 2021 Precursor Clarification.
116 EPA’s February 2020 Modeling TSD, 21.
117 CARB Staff Report, Appendix C, 15.
118 Annual average ammonia emissions are
projected to decrease 4.6 tpd (1.4 percent) from
2013 to 2024. 2018 PM2.5 Plan, Appendix B, Table
B–5.
114 CARB
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the ammonia sensitivity modeling for
the San Joaquin Valley, which showed
that PM2.5 concentrations will be less
sensitive to ammonia reductions as NOX
emissions go down in the future (i.e.,
the PM2.5 impacts were much smaller in
the 2020 and 2024 future modeled cases
compared to the 2013 base year).
The State projected that NOX
emissions in the San Joaquin Valley
would decrease by 36 percent from 2013
to 2020, and by 53 percent from 2013 to
2024, while ammonia emissions would
remain relatively flat, thereby increasing
the relative abundance of ammonia.119
Based on the Plan’s emissions reduction
projections combined with the research
study conclusions, the State relies on
the modeled responses for the future
years, rather than the 2013 base year,
stating that the future year NOX
emissions are more representative of
San Joaquin Valley emissions
conditions.120 The State references the
Draft PM2.5 Precursor Guidance, which
notes that it may be appropriate to
model future conditions that are more
representative of current atmospheric
conditions and those conditions
expected closer to the attainment date.
The State concludes that this in fact
applies to the San Joaquin Valley.121
With respect to the State’s selection of
30 percent as an upper bound on the
ammonia reductions to model, the State
described its review of the most
important ammonia source categories in
the San Joaquin Valley, existing control
measures that affect ammonia emissions
from these sources, additional
mitigation options for these sources, and
information provided in the PM2.5
Precursor Guidance about ammonia
reductions achieved nationwide from
2011 to 2017.122 The primary sources of
ammonia emissions identified in the
2018 PM2.5 Plan are: (1) Confined
animal facilities (CAFs); (2) agricultural
fertilizer; (3) biosolids, animal manure,
and poultry litter operations; and (4)
organic material composting
operations.123 CAFs are subject to
District Rule 4570; biosolids, animal
manure, and poultry litter operations
are subject to District Rule 4565; and
organic material composting operations
are subject to District Rule 4566.
Although these District rules explicitly
apply only to VOC emissions from these
sources, the State concludes that these
119 2018
PM2.5 Plan, Appendix G, 8–9.
at 9.
121 Id (referencing Draft PM
2.5 Precursor
Guidance, 33). See also PM2.5 Precursor Guidance,
35.
122 2018 PM
2.5 Plan, Appendix G and Appendix
C, section C–25, and CARB’s October 2019
Precursor Clarification.
123 2018 PM
2.5 Plan, Appendix C, section C–25.
120 Id.
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53161
rules also reduce ammonia emissions.
Appendix C of the 2018 PM2.5 Plan cites
several scientific studies that address
the correlation between VOC and
ammonia emissions from these
emissions sources.124 Based on these
evaluations, the State concludes that
ammonia control measures achieving
even the low end of the range (30
percent) are not feasible for
implementation in the San Joaquin
Valley and that it is therefore reasonable
to treat a 30 percent ammonia reduction
as an upper bound for modeling in the
precursor demonstration.
In summary, the State’s sensitivity
analysis presents a range of PM2.5
responses to ammonia emissions
reductions depending on base year
versus future year, and on the scale of
emissions reductions that may be
possible. The Plan provides the State’s
bases for finding that the future year
sensitivity results better represent
conditions in the San Joaquin Valley
than the 2013 base year and for finding
a 30 percent ammonia reduction to be
a reasonable upper bound for modeled
ammonia emissions reductions in
assessing the ammonia contribution.
Based on these analyses, the State
concludes that ammonia does not
contribute significantly to ambient
PM2.5 levels above the 1997 24-hour
PM2.5 NAAQS in the San Joaquin
Valley.
b. SOX
For SOX, the State compared the 24hour precursor contributions to the
recommended draft contribution
threshold of 1.3 mg/m3 in the Draft PM2.5
Precursor Guidance. For modeled SOX
emissions reductions of 30 percent and
70 percent, the ambient PM2.5 responses
in 2013 ranged from ¥1.4 to 0.5 mg/m3
across 15 monitoring sites, which all fall
below the 1.3 mg/m3 draft contribution
threshold, and hence also below the
contribution threshold of 1.5 mg/m3 in
the final version of the PM2.5 Precursor
Guidance.125 The response was below
zero at most monitoring sites, indicating
an increase, rather than a decrease, in
ambient PM2.5 in response to SOX
emissions reductions (i.e., a disbenefit).
Only the Stockton and Manteca sites
had slightly positive responses to 30
percent and 70 percent emissions
reductions, and the Tranquillity site
also had a slightly positive response
only to a 30 percent reduction. For the
15 sites, in 2020, the responses to 30
percent and 70 percent emissions
reductions ranged from ¥1.3 mg/m3 to
124 Id.
at C–314 and following.
PM2.5 Plan, Appendix G, Table 8 and
125 2018
Table 9.
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0.5 mg/m3 while for 2024, the responses
ranged from ¥1.1 mg/m3 to 0.6 mg/m3;
these are also all below the contribution
threshold, with most sites showing a
disbenefit from SOX reductions.126 The
Stockton, Manteca, and Tranquillity
sites showed the same pattern of slight
benefits as for 2013.127 For further
detail, please see the EPA’s February
2020 Precursor TSD, Table 3 and the
2018 PM2.5 Plan, Appendix G, tables 8
and 9 and Appendix K, tables 46, 48,
and 50.
CARB also included additional
information regarding emissions trends
and an evaluation of the SOX emissions
reduction disbenefit. We summarize this
additional information below and
provide a more detailed evaluation in
the EPA’s February 2020 Precursor TSD.
In terms of emissions trends, the State
found that SOX emissions decreased
from 2013 to 2014 and then were
expected to very gradually rise to 7.8
tpd in 2020 and 8.0 tpd in 2024.128
Given that projected SOX emissions are
very similar in 2020 and 2024, the State
concluded that the 2020 and 2024
sensitivity results were redundant.
Comparing the ambient responses in
2013 and 2024, the State found that the
responses were slightly less negative or,
for a small number of sites, slightly
higher in 2024, but still no more than
0.6 mg/m3 in response to a 70 percent
SOX emissions reduction.129 This
supports the State’s conclusion as to the
overall disbenefit of reducing SOX
emissions.
To explain the SOX emissions
reduction disbenefit that is observed in
some cases, CARB refers to the nonlinearity of inorganic aerosol
thermodynamics, as described in a
study by West et al.130 That paper
discusses how, under certain
conditions, reducing SOX could free
ammonia to combine with nitrate,
increasing overall PM2.5 mass. To
investigate this issue further, CARB
conducted simulations with the
ISORROPIA inorganic aerosol
thermodynamic equilibrium model used
within the CMAQ model and provided
126 CARB’s September 2019 Precursor
Clarification, 2020 analysis tables 15 and 16, and
2024 analysis tables 15 and 16.
127 2018 PM
2.5 Plan, Appendix K, Table 48 and
Table 50.
128 2018 PM
2.5 Plan, Appendix G, Figure 4.
129 CARB’s September 2019 Precursor
Clarification, 2013 analysis Table 16 and 2024
analysis Table 16.
130 2018 PM
2.5 Plan, Appendix K, section 5.6
(‘‘PM2.5 Precursor Sensitivity Analysis’’); and West,
J.J., Ansari, A.S., Pandis, S.N., 1999, Marginal PM2.5:
Nonlinear aerosol mass response to sulfate
reductions in the eastern United States, Journal of
the Air & Waste Management Association, 49,
1415–1424. https://doi.org/10.1080/
10473289.1999.10463973.
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clarifications to the EPA.131 In essence,
CARB states that for some conditions
typical of San Joaquin Valley,
ISORROPIA switches to a different
chemical regime in which the disbenefit
occurs. CARB states that it is not known
how well this model behavior reflects
the actual atmosphere, but CARB
accepts the results because it is a wellknown and widely used chemical
model.
Based on the small and mostly
negative modeled response of ambient
PM2.5 to SOX emissions reductions, and
based on its scientific understanding of
sulfate interactions with other
molecules in the air, the State concludes
that SOX does not contribute
significantly to ambient PM2.5 levels that
exceed the 1997 24-hour PM2.5 NAAQS
in the San Joaquin Valley.
c. VOC
For VOC, CARB compared the 24hour precursor contributions to the
EPA’s recommended draft contribution
threshold of 1.3 mg/m3. For a modeled
30 percent VOC emissions reduction,
the ambient PM2.5 responses in 2013
ranged from 0.1 to 1.9 mg/m3 across 15
monitoring sites, with two sites above
the 1.3 mg/m3 draft contribution
threshold.132 133 The 2020 responses
ranged from ¥0.1 to 0.6 mg/m3, with all
monitoring sites below the 1.3 mg/m3
draft contribution threshold, and hence
also below the contribution threshold of
1.5 mg/m3 that was finalized in the final
PM2.5 Precursor Guidance. The 2024
responses ranged from ¥0.4 to 0.0 mg/
m3, with all monitoring sites below both
the draft and final contribution
thresholds. For a 70 percent VOC
emissions reduction, the PM2.5
responses in 2013 ranged from 0.2 to 4.8
mg/m3, including responses above both
contribution thresholds at a majority of
sites. The 2020 response ranged from
¥0.2 to 1.5 mg/m3, with one site at the
final contribution threshold. The 2024
response ranged from ¥1.0 to 0.0 mg/m3
with monitoring sites below both the
contribution thresholds. In other words,
in response to either a 30 percent or a
70 percent reduction in VOC emissions,
CARB models a decrease in ambient
PM2.5 levels at all sites for 2013,
whereas for 2020, there were just small
decreases in ambient PM2.5 levels at
most sites and an increase at one site,
and for 2024 there were increases in
PM2.5 at all sites, i.e., a disbenefit. For
further detail, please see the EPA’s
February 2020 Precursor TSD, Table 4,
and the 2018 PM2.5 Plan, Appendix G,
tables 10 through 15.
CARB then considered additional
information to assess whether these
PM2.5 responses constituted a significant
contribution to ambient PM2.5 in the San
Joaquin Valley, including emissions
trends and an assessment of the
modeled disbenefit of VOC emissions
reductions. Regarding emissions trends,
CARB found that VOC emissions would
decrease approximately 30 tpd (or 9
percent) from 2013 to 2024, with
approximately 28 out of the 30 tpd
reduction taking place by 2020.134 The
State concludes that the formation of
ambient PM2.5 from VOC may therefore
differ in base and future years and that
the sensitivity analysis for 2013 is not
representative of current or future
conditions.
CARB explained the modeled
disbenefit of VOC reductions as follows:
Emissions of VOC and NOX react in the
atmosphere to form organic nitrate
species, such as peroxyacetyl nitrate
(PAN), meaning that some portion of the
NOX emissions is not available to react
with ammonia to form ammonium
nitrate. In other words, VOC emissions
are a ‘‘sink’’ for NOX emissions.
Reducing VOC emissions therefore
reduces the formation of organic
nitrates, so the sink is smaller and
nitrate molecules are freed to react with
ammonia to form particulate ammonium
nitrate.135 The State further explored the
VOC disbenefit based on a 2016 CARB
modeling assessment provided in
Appendix A (‘‘Air Quality Modeling’’)
of the ‘‘2016 Moderate Area Plan for the
2012 PM2.5 Standard’’ for the San
Joaquin Valley (‘‘2016 PM2.5 Plan’’),
which CARB submitted to the EPA as a
SIP revision on May 10, 2019.136
Based on its sensitivity-based analysis
of VOC emissions reductions, VOC
emissions trends, and the scientific
understanding of VOC chemistry in the
San Joaquin Valley, CARB concludes
that VOC emissions do not contribute
significantly to PM2.5 levels that exceed
the 1997 24-hour PM2.5 NAAQS in the
San Joaquin Valley.
134 2018
PM2.5 Plan, Appendix G, 19 and Figure
5.
131 CARB’s
June 2019 Precursor Clarification.
PM2.5 Plan, Appendix G, Table 10.
133 We note that one site (Visalia) has a modeled
response above the EPA’s final recommended
contribution threshold of 1.5 mg/m3 and one
additional site (Bakersfield-California Avenue) has
a modeled response below the 1.5 mg/m3 threshold
but above the EPA’s draft threshold of 1.3 mg/m3.
132 2018
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135 2018 PM
2.5 Plan, Appendix K, 72 (citing Meng,
Z., D. Dabdub, D., Seinfeld, J.H., Chemical Coupling
Between Atmospheric Ozone and Particulate
Matter, Science 277, 116 (1997). DOI: 10.1126/
science.277.5322.116).
136 2016 PM
2.5 Plan, Appendix A, A–57. See also
2018 PM2.5 Plan, Appendix K, section 5.6 (‘‘PM2.5
Precursor Sensitivity Analysis’’), 71–72.
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3. The EPA’s Review of the State’s
Submission
The EPA has evaluated the State’s
precursor demonstration consistent with
the PM2.5 SIP Requirements Rule and
the recommendations in the PM2.5
Precursor Guidance. Based on this
evaluation, the EPA agrees that NOX
emissions contribute significantly to
ambient PM2.5 levels that exceed the
1997 24-hour PM2.5 NAAQS in the San
Joaquin Valley and that NOX emissions
sources, therefore, remain subject to
control requirements under subparts 1
and 4 of the part D, title I of the Act.
For the reasons provided below, the
EPA proposes to approve the State’s
demonstration that ammonia, SOX, and
VOC emissions do not contribute
significantly to ambient PM2.5 levels that
exceed the 1997 24-hour PM2.5 NAAQS
in the San Joaquin Valley.
Regarding the State’s analytical
approach, the EPA finds that the State
based its analyses on the latest available
data and studies concerning ambient
PM2.5 formation in the San Joaquin
Valley from precursor emissions.
Regarding the required concentrationbased analysis, the EPA finds that the
State assessed the absolute annual
average contribution of each precursor
in ambient PM2.5 (i.e., in 2015). On the
basis of the absolute concentrations
being well above the EPA’s
recommended contribution thresholds
for both the 24-hour and annual average
NAAQS, the State proceeded with its
sensitivity-based analysis, which is the
recommended sequence under the final
PM2.5 Precursor Guidance.137
With respect to the sensitivity-based
analysis, we find that the State
performed its analyses following the
steps of the EPA’s recommended
approach—i.e., for each modeled year
and percent precursor emissions
reduction, the State estimated the
ambient PM2.5 response using the
procedure recommended in the PM2.5
Precursor Guidance and compared the
result to the recommended contribution
threshold. The EPA also finds that the
performance of the photochemical
model was adequate for use in
estimating the ambient PM2.5 responses,
as discussed in section J (‘‘Air Quality
Model Performance’’) of the EPA’s
‘‘Technical Support Document, EPA
Evaluation of Air Quality Modeling, San
Joaquin Valley PM2.5 Plan for the 2006
PM2.5 NAAQS,’’ February 2020 (‘‘EPA’s
137 For
further discussion of the EPA’s evaluation
of the State’s concentration-based analysis, see the
EPA’s February 2020 Precursor TSD, sections
entitled ‘‘Concentration-based analysis’’ within the
EPA’s evaluation for each of ammonia, SOX, and
VOC.
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February 2020 Modeling TSD’’). The
State considered the EPA’s
recommended range of emissions
reductions (30 percent to 70 percent) for
the 2013 base year, the projected 2020
attainment year for the 1997 24-hour
PM2.5 NAAQS, and the projected 2024
attainment year for the 2006 PM2.5
NAAQS, and quantified the estimated
response of ambient PM2.5
concentrations to precursor emissions
changes for the first time in a PM2.5 SIP
submission for the San Joaquin Valley.
The EPA finds that such quantification
and CARB’s consideration of additional
information provide an informed basis
on which to make a determination as to
whether ammonia, SOX, and VOC do or
do not contribute significantly to
ambient PM2.5 levels that exceed the
1997 24-hour PM2.5 NAAQS in the San
Joaquin Valley.138 Therefore, we turn to
our evaluation of the State’s
determination for each of these three
precursor pollutants.
a. Ammonia
For ammonia, as detailed above,
CARB estimated the ambient PM2.5
response to both a 30 percent and a 70
percent emissions reduction. We find
that it was appropriate for the State to
consider additional information to
interpret those results to determine
whether the ammonia contribution is
significant. The primary conclusion
demonstrated by the State’s analysis of
additional information is that
ammonium nitrate formation is NOXlimited. As discussed in more detail
below, we agree with this conclusion.
We have evaluated CARB’s
determination that a projected future
year is more representative of
conditions in the San Joaquin Valley for
sensitivity-based analyses and that 30
percent is a reasonable upper bound for
ammonia emissions reductions to assess
the precursor contribution, as discussed
below.
The State provided ample information
from scientific studies based on ambient
measurements to help assess the
estimated sensitivity of ambient PM2.5 to
ammonia reductions. Conclusions based
on ambient data are particularly
relevant because they provide direct
evidence of the chemical state of the
atmosphere and are not dependent on
modeled estimates of emissions or
modeled ambient PM2.5 concentrations.
Measurements represent the ‘‘real
138 The State did not evaluate the 2015 Serious
area attainment year. Because the year has passed
and the area failed to attain by the Serious area
attainment date, we will evaluate the precursor
analysis for the Serious area plan based on the
current section 189(d) projected attainment date of
December 31, 2020.
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world’’ result of the pollutants’ differing
geographic distributions, the various
meteorological and chemical factors
influencing their conversion to
particulate, and their removal from the
atmosphere by deposition and other
processes. The observed abundance of
ammonia relative to nitric acid, and the
positive amount of chemically excess
ammonia, both provide strong evidence
that ammonia is not the limiting
pollutant for particulate ammonium
nitrate formation. They also support the
State’s conclusion that PM2.5
concentrations are insensitive to
ammonia emissions reductions.
The relative amount of ammonia and
NOX emissions is one of the most
critical factors in determining the
sensitivity of ambient PM2.5 to ammonia
reductions. We note that the model
response to precursor reductions may be
unrealistically large due to the
underestimation of ammonia emissions
and therefore of the ratio of ammonia to
NOX emissions. There is evidence that
ammonia emissions may be
underestimated based on direct
measurements of ammonia emissions
flux during two measurement
campaigns, as discussed in the EPA’s
February 2020 Precursor TSD. If
ammonia emissions were higher in the
modeling, then ammonia would be more
abundant relative to nitrate and
particulate nitrate formation would be
more NOX-limited and less sensitive to
ammonia reductions. This would make
the model response more consistent
with the ambient measurement studies,
which suggest a very low sensitivity to
ammonia. This evidence indicates that
ammonia contribution to PM2.5 levels
above the standard is likely to be less
than estimated by the State’s modeling
in each of the three years. In comparison
to the 2013 and 2020 modeling, the
modeling for the year 2024 incorporates
lower NOX emissions and so has a larger
abundance of ammonia relative to
nitrate, more similar to the studies’
ambient measurements. Thus, the 2024
response to ammonia reductions is
likely to be more reliable than the 2013
and 2020 responses and appears to be
more representative of current
atmospheric conditions despite the use
of emissions projections for a future
year.
The relative sizes of the ammonia and
NOX precursor emissions inventories
after accounting for their differing
molecular weights are a rough indicator
of which pollutant is the limiting
pollutant for production of ammonium
nitrate because ammonium nitrate forms
from a one-to-one ratio of molecules
derived from each precursor (i.e., one
ammonium nitrate forms from one
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ammonium and one nitrate). However,
unlike measurements and
photochemical modeling, a simple
emissions ratio does not account for
various processes mentioned above; it
assumes all the emitted molecules find
one another and react. The State found
ammonia to be roughly three times as
abundant as NOX in 2013 after
accounting for their differing molecular
weights, and even more abundant in
future years. The EPA repeated the
exercise to account for SOX and found
that the ratio of total ammonia to the
ammonia needed to react with both
nitrate and sulfate ranged from 2.7 in
2013 to 5.6 in 2028. These results are
approximately the same as the CARB
NOX-only results because SOX
emissions are very small relative to NOX
and ammonia emissions (e.g., in 2013,
winter daily emissions were 8.4 tpd of
SOX versus 300.5 tpd of NOX and 309.8
tpd of ammonia).139 These observations
support the State’s finding that PM2.5 is
expected to be relatively insensitive to
ammonia reductions, though they are
not definitive on their own.
The State also points to large
decreases or projected decreases in NOX
emissions in the San Joaquin Valley
from 2013 to 2024, including a 36
percent reduction from baseline
measures by 2020, and a 53 percent
reduction by 2024, while CARB projects
that ammonia emissions will remain
roughly constant (i.e., decreasing 1–2
percent). In conjunction with the
ambient evidence that ammonia is
already chemically overabundant
relative to NOX in the San Joaquin
Valley, this indicates that the
overabundance will become even
greater in the future, and thus ambient
PM2.5 is expected to be even less
responsive to ammonia reductions. This
adds conservatism to the State’s
conclusions about ammonia sensitivity
based on the scientific studies.
While the base year for an attainment
plan for a given nonattainment area is
generally more representative of current
conditions, there can be situations in
which is it more appropriate to use
future conditions representative of
when sources will operate, and the EPA
believes that states may use either a base
year or a future year for modeling an
ambient PM2.5 response to precursor
emissions reductions, provided the state
explains how the choice of analysis year
and associated assumptions are
appropriate.140 The 2013 modeled
responses cannot be considered current
at the present time, in comparison to the
139 2018 PM
2.5 Plan, Appendix B, tables B–2, B–
3, and B–4.
140 PM
2.5 Precursor Guidance, 35–36.
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2020 results. Large NOX emissions
reductions have occurred from 2013–
2020 and are projected to continue to
occur on through 2024, continuing to
decrease the ratio of NOX to ammonia.
In light of this ongoing trend, and the
ambient data indicating that models
underestimate ammonia, the EPA
believes that future year results, which
more accurately reflect the expected
NOX to ammonia ratio, will continue to
be representative, unlike the 2013 base
year. These reductions are the result of
regulations put in place by past air
quality planning decisions and they will
occur regardless of the actions that are
being proposed herein. In assessing the
effect of potential ammonia reductions,
the EPA believes it is reasonable to
account for these NOX reductions. In
addition, as noted above, the greater
abundance of ammonia relative to NOX
in the 2024 year modeling is more
consistent with recent ambient
measurements, which suggest that the
2024 responses are more representative
of current atmospheric conditions than
the other model years for assessing
sensitivity to ammonia reductions.
Therefore, in consideration of the
scientific studies and emissions trends,
including the projected large amount of
NOX emissions reductions through the
attainment period, the EPA agrees that
use of a future year is appropriate.
Given the available research and
ambient data, we conclude that the
modeled 2024 year is the most
representative of conditions in the San
Joaquin Valley.
Even if we were to set aside the more
representative 2024 modeling, in the
2020 modeled responses, only the
Bakersfield-Planz site is above the
contribution threshold, at 1.9 mg/m3. A
single value above the threshold is not
determinative, particularly in light of
the additional information provided
above, indicating that the modeled
values overestimate the contribution of
ammonia to ambient PM2.5 levels, and
that the trend continues toward less
contribution in the future as the ratio of
NOX to ammonia continues to drop.
Moreover, the monitored 2020 design
value is attaining the 1997 24-hour
PM2.5 NAAQS because, as discussed
above and in section V of this proposal,
at the current time there are not PM2.5
levels above the NAAQS. This is further
evidence that the single 2020 modeled
response above the contribution
threshold is not a significant
contribution to PM2.5 levels in excess of
the NAAQS, even if the 2020 modeling
were considered representative.
In the context of interpreting the full
set of modeling results for ammonia
emissions reductions, the EPA also
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considered the State’s conclusion that
the absence of available ammonia
controls for sources in the San Joaquin
Valley supports its decision to treat a 30
percent reduction as a reasonable upper
bound on the ammonia emissions
reductions to model in estimating the
precursor contribution. As the State
correctly notes, the 30 percent to 70
percent range recommended by the EPA
is based on historical NOX and SOX
emissions reductions, and changes in
ammonia emissions levels nationally
from 2011 to 2017 ranged from a 9
percent decrease to a 6 percent
increase.141 The State’s descriptions of
past research relied upon to develop
existing rules that apply to ammonia
emissions sources, as well as ongoing
research, show that it has considered
the availability of ammonia controls
both in the past and present context,
and that the State has a basis for its
conclusion that 30 percent is a
reasonable upper bound on achievable
reductions for ammonia.
In sum, we find that the State
quantified the sensitivity of ambient
PM2.5 levels to reductions in ammonia
using appropriate modeling techniques
that performed well, and that the State’s
analysis and use of future year
sensitivity data, both 2020 and 2024, is
well-supported. We also find that the
State adequately documented its basis
for using a 30 percent reduction in
ammonia emissions as an upper bound
in the modeling to assess ambient
sensitivity to ammonia emissions
reductions. Based on these
considerations, the EPA proposes to
approve the State’s demonstration that
ammonia emissions do not contribute
significantly to ambient PM2.5 levels that
exceed the 1997 24-hour PM2.5 NAAQS
in the San Joaquin Valley.
b. SOX
For SOX, the State found that the
ambient PM2.5 responses to SOX
emissions reductions were below the
EPA’s recommended contribution
threshold of 1.3 mg/m3 in the Draft PM2.5
Precursor Guidance (and below the EPA
recommended threshold of 1.5 mg/m3 in
the final PM2.5 Precursor Guidance), and
that for most sites there would be an
increase in ambient PM2.5 levels in
response to SOX reductions (i.e., a
disbenefit). The EPA has evaluated the
State’s analysis of this disbenefit and
resulting conclusion regarding
significance.
Because the results of the sensitivity
analysis were all below the EPA’s
recommended 24-hour contribution
thresholds at both the 30 percent and 70
141 Id.
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percent emissions reductions, and in
both the 2013 base year and 2020 (and
2024) future year, it is not necessary to
distinguish between the timing and
scale of emissions reductions with
respect to the response of ambient PM2.5
levels as in the ammonia evaluation
where the results diverged according to
scale and timing of modeled emissions
reductions. The EPA’s February 2020
Precursor TSD contains additional
detail on the EPA’s evaluation of SOX as
a PM2.5 precursor, including the
disbenefit associated with a reduction in
SOX emissions. Accordingly, we find
that the State’s decision to rely on the
2013 sensitivity modeling results for a
30 percent SOX reduction is acceptable.
Therefore, on the basis of the modeled
ambient PM2.5 response to both a 30
percent and 70 percent reduction in
SOX emissions in 2013, and on the facts
and circumstances of the area, the EPA
proposes to approve the State’s
demonstration that SOX emissions do
not contribute significantly to ambient
PM2.5 levels that exceed the 1997 24hour PM2.5 NAAQS in the San Joaquin
Valley.
c. VOC
For VOC, the State found that the
ambient PM2.5 response to VOC
emissions reductions were generally
below the EPA’s recommended
contribution threshold of 1.3 mg/m3 in
the Draft PM2.5 Precursor Guidance and
below the EPA’s recommended
threshold of 1.5 mg/m3 in the final PM2.5
Precursor Guidance, and often predicted
an increase in ambient PM2.5 levels in
response to such reductions (i.e., a
disbenefit), except for a 70 percent
emissions reduction for the 2013 base
year, where the State predicted the
ambient PM2.5 response to be above both
recommended thresholds at a majority
of sites. The EPA has evaluated and
agrees with the State’s determination
that the modeling for future years is
more representative of conditions in the
San Joaquin Valley than the 2013
modeling for sensitivity-based analyses
and the State’s resulting conclusion as
to whether the contribution from VOC
emissions is significant.
Regarding emissions trends, the EPA
agrees that the 8.6 percent decrease in
VOC emissions from 2013 to 2020 and
the 9.2 percent projected decrease from
2013 to 2024 favors reliance on the
future year modeling results.
Furthermore, there is a large decrease in
NOX emissions over this period, as
discussed in the EPA’s evaluation of
ammonia, which affects the atmospheric
chemistry with respect to ambient PM2.5
formation from VOC emissions. The 9
percent VOC emissions reductions and
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the NOX emissions reductions are
projected to result from implementation
of existing baseline measures. We
therefore find it reasonable to rely on
future year 2020 or 2024 modeled
responses to VOC emissions reductions,
and both years show a disbenefit from
VOC emissions reductions. The EPA
also finds that the State provided a
reasonable explanation for the VOC
reduction disbenefit and evidence that it
occurs in the San Joaquin Valley.
For these reasons, we propose to
approve the State’s demonstration that
VOC emissions do not contribute
significantly to ambient PM2.5 levels that
exceed the 1997 24-hour PM2.5 NAAQS
in the San Joaquin Valley.
C. Attainment Plan Control Strategy
1. Statutory and Regulatory
Requirements
Section 189(b)(1)(B) of the Act
requires for any Serious PM2.5
nonattainment area that the state submit
provisions to assure that BACM for the
control of PM2.5 and PM2.5 precursors
shall be implemented no later than four
years after the date the area is
reclassified as a Serious area. The EPA
has defined BACM in the PM2.5 SIP
Requirements Rule to mean ‘‘any
technologically and economically
feasible control measure that . . . can
achieve greater permanent and
enforceable emissions reductions of
direct PM2.5 emissions and/or emissions
of PM2.5 plan precursors from sources in
the area than can be achieved through
the implementation of RACM on the
same source(s). BACM includes best
available control technology
(BACT).’’ 142
Because the 2015 Serious area
attainment date has passed, and the EPA
found that the area failed to attain by
the Serious area attainment date, we are
evaluating the submission for
compliance with the BACM/BACT
requirements now, in conjunction with
the State’s SIP submission intended to
meet both the Serious area plan and
section 189(d) plan requirements.
The EPA generally considers BACM a
control level that goes beyond existing
RACM-level controls, for example by
expanding the use of RACM controls or
by requiring preventative measures
instead of remediation.143 Indeed, as
142 40
CFR 51.1000 (definitions). In longstanding
guidance, the EPA has similarly defined BACM to
mean, ‘‘among other things, the maximum degree of
emissions reduction achievable for a source or
source category, which is determined on a case-bycase basis considering energy, environmental, and
economic impacts.’’ General Preamble Addendum,
42010, 42013.
143 81 FR 58010, 58081 and General Preamble
Addendum, 42011, 42013.
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implementation of BACM and BACT is
required when a Moderate
nonattainment area is reclassified as
Serious due to its inability to attain the
NAAQS through implementation of
‘‘reasonable’’ measures, it is logical that
‘‘best’’ control measures should
represent a more stringent and
potentially more costly level of
control.144 If RACM and RACT level
controls of emissions have been
insufficient to reach attainment, the
CAA contemplates the implementation
of more stringent controls, controls on
more sources, or other adjustments to
the control strategy are necessary to
attain the NAAQS in the area.
Under the PM2.5 SIP Requirements
Rule, those control measures that
otherwise meet the definition of BACM/
BACT but ‘‘can only be implemented in
whole or in part beginning four years
after reclassification’’ are referred to as
‘‘additional feasible measures.’’ 145 In
accordance with the requirements of
CAA section 172(c)(6), a Serious area
plan must include any additional
feasible measures to control emissions
of direct PM2.5 and PM2.5 precursors that
are necessary and appropriate to
provide for attainment of the relevant
NAAQS as expeditiously as practicable
and no later than the applicable
attainment date.146
Consistent with longstanding
guidance provided in the General
Preamble Addendum, the preamble to
the PM2.5 SIP Requirements Rule
discusses the following steps for
determining BACM and BACT and
additional feasible measures:
(1) Develop a comprehensive
emissions inventory of the sources of
PM2.5 and PM2.5 precursors;
(2) Identify potential control
measures;
(3) Determine whether an available
control measure or technology is
technologically feasible;
(4) Determine whether an available
control measure or technology is
economically feasible; and
(5) Determine the earliest date by
which a control measure or technology
can be implemented in whole or in
part.147
The EPA allows consideration of
factors such as physical plant layout,
144 Id. and General Preamble Addendum, 42009–
42010.
145 40 CFR 51.1000, 40 CFR 51.1010(a)(4)(ii).
146 Because the Serious area attainment year has
passed and the area failed to attain by the Serious
area attainment date, we will evaluate the BACM/
BACT and additional feasible measure analysis for
the Serious area plan with respect to the current
section 189(d) projected attainment date of
December 31, 2020.
147 81 FR 58010, 58083–58085.
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energy requirements, needed
infrastructure, and workforce type and
habits when considering technological
feasibility. For purposes of evaluating
economic feasibility, the EPA allows
consideration of factors such as the
capital costs, operating and
maintenance costs, and cost
effectiveness (i.e., cost per ton of
pollutant reduced by a measure or
technology) associated with the measure
or control.148
Once these analyses are complete, the
state must use this information to
develop enforceable control measures
and submit them to the EPA for
evaluation as SIP revisions to meet the
basic requirements of CAA section 110
and any other applicable substantive
provisions of the Act. The EPA is using
these steps as guidelines in the
evaluation of the BACM and BACT
measures and related analyses in the
SJV PM2.5 Plan. Furthermore, because
the EPA has not previously taken action
to approve the California SIP as meeting
the subpart 4 Moderate area planning
requirements under CAA section 189 for
the 1997 24-hour PM2.5 NAAQS for the
San Joaquin Valley area, the EPA is
reviewing the SJV PM2.5 Plan for
compliance with those requirements.149
The overarching requirement for the
CAA section 189(d) attainment control
strategy is that it provides for attainment
of the NAAQS as expeditiously as
practicable.150 The control strategy must
include any additional measures
(beyond those already adopted in
previous nonattainment plans for the
area as RACM/RACT or BACM/BACT)
that are needed for the area to attain
expeditiously. This includes reassessing
any measures previously rejected during
the development of any Moderate area
or Serious area attainment plan control
strategy.151 The state must also
demonstrate that it will, at a minimum,
achieve an annual five percent
reduction in emissions of direct PM2.5 or
any PM2.5 plan precursor from sources
148 40 CFR 51.1010(a)(3) and 81 FR 58010, 58041–
58042.
149 The EPA does not normally conduct a separate
evaluation to determine whether a Serious area
plan’s measures also meet the RACM requirements.
As explained in the General Preamble Addendum,
we interpret the BACM requirement as generally
subsuming the RACM requirement—i.e., if we
determine that the measures are indeed the ‘‘best
available,’’ we have necessarily concluded that they
are ‘‘reasonably available.’’ (General Preamble
Addendum, 42010). Therefore, a separate analysis
to determine if the measures represent a RACM
level of control is not necessary. A proposed
approval of a Plan’s provisions concerning
implementation of BACM is also a proposed finding
that the Plan provides for the implementation of
RACM.
150 81 FR 58010, 58100.
151 40 CFR 50.1010(c)(2)(ii).
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in the area, based on the most recent
emissions inventory for the area.152
In the PM2.5 SIP Requirements Rule,
the EPA clarified its interpretation of
the statutory language in CAA section
189(d) requiring a state to submit a new
attainment plan to achieve annual
reductions ‘‘from the date of such
submission until attainment,’’ to mean
annual reductions beginning from the
due date of such submission until the
new projected attainment date for the
area based on the new or additional
control measures identified to achieve at
least five percent emissions reductions
annually.153 This interpretation is
intended to make clear that even if a
state is late in submitting its CAA
section 189(d) plan, the area must still
achieve its annual five percent
emissions reductions beginning from
the date by which the state was required
to make its CAA section 189(d)
submission, not by some later date.
Because the deadline for California to
submit a section 189(d) plan for the
1997 PM2.5 NAAQS in the San Joaquin
Valley was December 31, 2016, one year
after the December 31, 2015 attainment
date for these NAAQS under CAA
section 188(c)(2), the starting point for
the five percent emissions reduction
requirement under section 189(d) for
this area is 2017.
2. Summary of the State’s Submission
and the EPA’s Evaluation and Proposed
Action
a. Control Strategy
For the Serious area and section
189(d) plan requirements for the 1997
24-hour PM2.5 NAAQS the State based
the control strategy in the SJV PM2.5
Plan on ongoing emissions reductions
from baseline control measures.154 As
we use the term here, baseline measures
are State and District regulations
adopted prior to the development of the
SJV PM2.5 Plan that continue to achieve
emissions reductions through the
projected 2020 attainment year for the
1997 24-hour PM2.5 NAAQS and
beyond. The State describes the baseline
measures in the 2018 PM2.5 Plan in
Chapter 4,155 Appendix C (‘‘Stationary
Source Control Measure Analyses’’), and
Appendix D (‘‘Mobile Source Control
Measure Analyses’’). The State
incorporates reductions generated by
152 CAA
section 189(d) and 40 CFR 51.1010(c).
FR 58010, 58101.
154 Because the 2015 Serious area attainment date
has passed, and the EPA found that the area failed
to attain by the Serious area attainment date, we are
evaluating the control strategy for the Serious area
requirements based on the timeline associated with
the current section 189(d) projected attainment date
of December 31, 2020.
155 2018 PM
2.5 Plan, Chapter 4, Table 4–2.
153 81
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these baseline measures into the
projected baseline inventories and
reductions resulting from District
measures are individually quantified in
Appendix C.
In the 2018 PM2.5 Plan, CARB
indicates that mobile sources emit over
85 percent of the NOX emissions in the
San Joaquin Valley and that CARB has
adopted and amended regulations to
reduce public exposure to diesel
particulate matter, which includes
direct PM2.5 and NOX, from ‘‘fuel
sources, freight transport sources like
heavy-duty diesel trucks, transportation
sources like passenger cars and buses,
and non-road sources like large
construction equipment.’’ 156
Given the need for substantial
emissions reductions from mobile and
area sources to meet the NAAQS in
California nonattainment areas, the
State of California has developed
stringent control measures for on-road
and non-road mobile sources and the
fuels that power them. California has
unique authority under CAA section
209 (subject to a waiver or authorization
as applicable by the EPA) to adopt and
implement new emissions standards for
many categories of on-road vehicles and
engines and new and in-use non-road
vehicles and engines. The EPA has
approved many such mobile source
regulations for which it has issued
waiver authorizations as revisions to the
California SIP.157
CARB’s mobile source program
extends beyond regulations that are
subject to the waiver or authorization
process set forth in CAA section 209 to
include standards and other
requirements to control emissions from
in-use heavy-duty trucks and buses,
gasoline and diesel fuel specifications,
and many other types of mobile sources.
Generally, these regulations have also
been submitted and approved as
revisions to the California SIP.158
As to stationary and area sources, the
SJV PM2.5 Plan indicates that regulations
adopted for prior attainment plans
156 2018 PM
2.5 Plan, Chapter 4, 4–9. For CARB’s
BACM analysis for mobile source measures, see
2018 PM2.5 Plan, Appendix D, including analyses
for on-road light-duty vehicles and fuels (starting on
page D–17), on-road heavy-duty vehicles and fuels
(starting on page D–35), and non-road sources
(starting on page D–64).
157 For example, see 81 FR 39424 (June 16, 2016);
82 FR 14446 (March 21, 2017); and 83 FR 23232
(May 18, 2018).
158 For example, see the EPA’s approval of
standards and other requirements to control
emissions from in-use heavy-duty diesel trucks (77
FR 20308, April 4, 2012), revisions to the California
on-road reformulated gasoline and diesel fuel
regulations (75 FR 26653, May 12, 2010), and
revisions to the California motor vehicle inspection
and maintenance program (75 FR 38023, July 1,
2010).
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continue to reduce emissions of NOX
and direct PM2.5.159 Specifically, Table
4–1 of the 2018 PM2.5 Plan identifies 33
District measures that limit NOX and
direct PM2.5 emissions.160 The EPA has
approved each of the identified
measures into the California SIP,161
with two exceptions.
First, the District amended Rule 4905
(‘‘Natural Gas-fired, Fan-type,
Residential Central Furnaces’’) on
October 15, 2020, to extend the period
during which manufacturers may pay
emissions fees in lieu of meeting the
rule’s NOX emissions limits.162 CARB
submitted the amended rule to the EPA
on December 30, 2020,163 and the EPA
has not yet proposed any action on this
submission. The EPA approved a prior
version of Rule 4905 into the California
SIP on March 29, 2016.164 As part of
that rulemaking, the EPA noted that
because of the option in Rule 4905 to
pay mitigation fees in lieu of
compliance with emissions limits,
emissions reductions associated with
the rule’s emissions limits would not be
creditable in any attainment plan
without additional documentation.165
Until the District submits the necessary
documentation to credit emissions
reductions achieved by Rule 4905
toward an attainment control strategy,
this rule is not creditable for SIP
purposes. The Plan indicates that the
District attributed 0.06 tpd of NOX
reductions between 2013 and 2020 to
Rule 4905.166 These emissions
reductions have de minimis impacts on
the attainment demonstration for the
1997 24-hour PM2.5 NAAQS in the SJV
PM2.5 Plan.
159 2018 PM
2.5 Plan, Chapter 4, 4–3. For the
District’s BACM analysis of stationary and area
source measures, see 2018 PM2.5 Plan, Appendix C.
160 2018 PM
2.5 Plan, Chapter 4, Table 4–1.
161 See EPA Region IX’s website for information
on District control measures that have been
approved into the California SIP, available at:
https://www.epa.gov/sips-ca/epa-approved-sanjoaquin-valley-unified-air-district-regulationscalifornia-sip.
162 SJVUAPCD, Final Draft Staff Report with
Appendix for Proposed Amendments to Rule 4905,
‘‘Adopt Proposed Amendments to Rule 4905
(Natural Gas-fired, Fan-type Central Furnaces),’’ 2.
163 Letter dated December 28, 2020, from Richard
W. Corey, Executive Officer, CARB, to John
Busterud, Regional Administrator, EPA Region 9.
CARB’s submittal letter formally withdrew a
previously amended version of Rule 4905 adopted
by the District on June 21, 2018 and submitted to
the EPA by CARB on November 21, 2018.
164 81 FR 17390 (March 29, 2016) (approving Rule
4905 as amended January 22, 2015).
165 EPA, Region IX Air Division, ‘‘Technical
Support Document for EPA’s Proposed Rulemaking
for the California State Implementation Plan (SIP),
San Joaquin Valley Unified Air Pollution Control
District’s Rule 4905, Natural Gas-Fired, Fan-Type
Central Furnaces,’’ October 5, 2015, n. 8.
166 2018 PM
2.5 Plan, Appendix C, C–290.
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Second, the 2018 PM2.5 Plan lists Rule
4203 (‘‘Particulate Matter Emissions
from Incineration of Combustible
Refuse’’) as a baseline measure. This
rule has not been approved into the
California SIP.167 Appendix C of the
2018 PM2.5 Plan indicates, however, that
the emissions inventory for incineration
of combustible refuse is 0.00 tpd of NOX
and 0.00 direct PM2.5 from 2013 through
2020.168 Thus, although the District
included this rule as a baseline measure,
there are no meaningful reductions
associated with this rule that would
affect the attainment demonstration in
the SJV PM2.5 Plan.
In sum, although Table 4–1 of the
2018 PM2.5 Plan identifies two baseline
measures that are not creditable for SIP
purposes at this time, we find that the
total emissions reductions attributed to
these measures in the future baseline
inventories have de minimis effects on
the attainment demonstration in the
Plan.
b. Best Available Control Measures
We are evaluating the State’s BACM
demonstration for the 1997 24-hour
PM2.5 NAAQS against the section
189(b)(1)(B) Serious area plan BACM
requirement, and the section 189(d)
plan requirement to address all Serious
area plan requirements that the State
has not already met. Because we have
already found that the State failed to
attain the 1997 24-hour PM2.5 NAAQS
in the San Joaquin Valley area by the
Serious area attainment date, and
because we have not previously found
that the state has met the BACM
requirement for purposes of the 1997
24-hour PM2.5 NAAQS, we are
evaluating the State’s submission
against the Serious area BACM
requirement in light of the section
189(d) control plan timeline. The State’s
BACM demonstration is presented in
Appendix C (‘‘Stationary Source
Controls’’) and Appendix D (‘‘Mobile
Source Control Measure Analyses’’) of
the 2018 PM2.5 Plan.169 As discussed in
section IV.A of this proposed rule,
Appendix B (‘‘Emissions Inventory’’) of
the 2018 PM2.5 Plan contains the
planning inventories for direct PM2.5
and all PM2.5 precursors (NOX, SOX,
VOC, and ammonia) for the San Joaquin
167 The EPA does not have any pending SIP
submission for Rule 4203.
168 2018 PM
2.5 Plan, Appendix C, C–46.
169 Appendices C and D also present an MSM
analysis for the purposes of meeting a precondition
for an extension of the Serious area attainment date
under CAA section 188(e) for the 2006 PM2.5
NAAQS. The San Joaquin Valley area is not subject
to the MSM requirement for the 1997 24-hour PM2.5
NAAQS. Thus, the EPA is evaluating the Plan’s
control strategy for implementation of BACM and
BACT only.
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Valley nonattainment area together with
documentation to support these
inventories. Each inventory includes
emissions from stationary, area, on-road,
and non-road emissions sources, and
the State specifically identifies the
condensable component of direct PM2.5
for relevant stationary source and area
source categories. As discussed in
section IV.B of this proposed rule, the
State concludes that the Plan should
control emissions of PM2.5 and NOX to
reach attainment. Accordingly, the
BACM and BACT evaluation in the Plan
addresses potential controls for sources
of those pollutants.
For stationary and area sources, the
District identifies the sources of direct
PM2.5 and NOX in the San Joaquin
Valley that are subject to District
emissions control measures and
provides its evaluation of these
regulations for compliance with BACM
requirements in Appendix C of the 2018
PM2.5 Plan. As part of its process for
identifying candidate BACM and
considering the technical and economic
feasibility of additional control
measures, the District reviewed the
EPA’s guidance documents on BACM,
additional guidance documents on
control measures for direct PM2.5 and
NOX emissions sources, and control
measures implemented in other ozone
and PM2.5 nonattainment areas in
California and other states.170 The
District also provides an analysis of
several SIP-approved VOC regulations
that, according to the District, also
provide ammonia co-benefits.171 Based
on these analyses, the District concludes
that all best available control measures
for stationary and area sources are in
place in the San Joaquin Valley for NOX
and directly emitted PM2.5 for purposes
of meeting the BACM/BACT
requirement for the 1997 24-hour PM2.5
NAAQS. We provide an evaluation of
many of the District’s control measures
for stationary sources and area sources
in section III of the EPA’s 1997 24-hour
PM2.5 TSD together with
recommendations for possible future
improvements to these rules.
For mobile sources, CARB identifies
the sources of direct PM2.5 and NOX in
the San Joaquin Valley that are subject
to the State’s emissions control
measures and provides its evaluation of
these regulations for compliance with
BACM requirements in Appendix D of
the 2018 PM2.5 Plan. Appendix D
describes CARB’s process for
determining BACM, including
identification of the sources of direct
PM2.5 and NOX in the San Joaquin
170 2018
171 2018
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Valley, identification of potential
control measures for such sources,
assessment of the stringency and
feasibility of the potential control
measures, and adoption and
implementation of feasible control
measures.172
Mobile source categories for which
CARB has primary responsibility for
reducing emissions in California
include most new and existing on- and
non-road engines and vehicles and
motor vehicle fuels. The SJV PM2.5
Plan’s BACM demonstration provides a
general description of CARB’s key
mobile source programs and regulations
and a comprehensive table listing onroad and non-road mobile source
regulatory actions taken by CARB since
1985.173
Appendix D of the 2018 PM2.5 Plan
also describes the current efforts of the
eight local jurisdiction metropolitan
planning organizations (MPOs) to
implement cost-effective transportation
control measures (TCMs) in the San
Joaquin Valley.174 TCMs are projects
that reduce air pollutants from
transportation sources by reducing
vehicle use, traffic congestion, or
vehicle miles traveled. TCMs are
currently being implemented in the San
Joaquin Valley as part of the Congestion
Mitigation and Air Quality cost
effectiveness policy adopted by the
eight local jurisdiction MPOs and in the
development of each Regional
Transportation Plan (RTP). The
Congestion Mitigation and Air Quality
policy, which is included in a number
of the District’s prior attainment plan
submissions for the ozone and PM2.5
NAAQS, provides a standardized
process for distributing 20 percent of the
Congestion Mitigation and Air Quality
funds to projects that meet a minimum
cost effectiveness threshold beginning
in fiscal year 2011. The MPOs revisited
the minimum cost effectiveness
standard during the development of
their 2018 RTPs and 2019 Federal
Transportation Improvement Program
and concluded that they were
implementing all reasonable
transportation control measures.175
Appendix D of the District’s ‘‘2016
Ozone Plan for 2008 8-Hour Ozone
Standard,’’ adopted June 16, 2016,
contains a listing of adopted TCMs for
the San Joaquin Valley.176
We have reviewed the State’s and
District’s analysis and determination in
the SJV PM2.5 Plan that their baseline
mobile, stationary, and area source
control measures meet the requirements
for BACM for sources of direct PM2.5
and applicable PM2.5 plan precursors
(i.e., NOX) for purposes of the 1997 24hour PM2.5 NAAQS. In our review, we
considered our evaluation of the State’s
and District’s rules in connection with
our approval of the demonstrations for
BACM (including BACT) and MSM for
the 2006 PM2.5 NAAQS.177 We find that
the evaluation processes followed by
CARB and the District in the SJV PM2.5
Plan to identify potential BACM were
generally consistent with the
requirements of the PM2.5 SIP
Requirements Rule, the State’s and
District’s evaluation of potential
measures is appropriate, and the State
and District have provided reasoned
justifications for their rejection of
potential measures based on
technological or economic infeasibility.
We also agree with the District’s
conclusion that all reasonable TCMs are
being implemented in the San Joaquin
Valley and propose to find that these
TCMs implement BACM for
transportation sources.
For the foregoing reasons, we propose
to find that the SJV PM2.5 Plan provides
for the implementation of BACM for
sources of direct PM2.5 and NOX as
expeditiously as practicable in
accordance with the requirements of
CAA section 189(b)(1)(B), and in
satisfaction of both the Serious area and
section 189(d) plan requirements.
c. Section 189(d) Five Percent
Requirement
The SJV PM2.5 Plan’s demonstration of
annual five percent reductions in NOX
emissions is in section 5.2 of the 2018
PM2.5 Plan. As shown in Table 3, the
demonstration uses the 2013 base year
inventory as the starting point from
which the five percent per year
emissions reductions are calculated and
uses 2017 as the year from which the
reductions start. The target required
reduction in 2017 is five percent of the
base year (2013) inventory, which is a
reduction of approximately 15.9 tpd of
NOX, and the targets for subsequent
years are additional reductions of five
percent per year until the 2020
attainment year. The projected
emissions inventories reflect NOX
emissions reductions achieved by
baseline control measures and the
demonstration shows that these NOX
emissions reductions are greater than
the required five percent per year.
TABLE 3—2017–2020 ANNUAL FIVE PERCENT EMISSIONS REDUCTIONS DEMONSTRATION FOR THE SAN JOAQUIN VALLEY
Year
2013
2017
2018
2019
2020
(base year) .............................................................................................
.................................................................................................................
.................................................................................................................
.................................................................................................................
.................................................................................................................
% Reduction
from 2013
base year
5% Target
(tpd NOX)
........................
5
10
15
20
........................
301.3
285.5
269.6
253.8
CEPAM
inventory
v1.05
(tpd NOX)
317.3
233.4
221.5
214.5
203.3
Meets 5%?
Yes.
Yes.
Yes.
Yes.
Source: 2018 PM2.5 Plan, Table 5–2.
The EPA proposes to find that the
State’s use of 2017 as the starting point
from which the five percent per year
emissions reductions should begin is
reasonable and consistent with the
CAA. As discussed in section IV.C.1 of
172 2018
PM2.5 Plan, Appendix D, Chapter II.
at Table 17.
174 Id. at D–127 and D–128.
173 Id.
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this document, the EPA interprets the
language under CAA section 189(d) to
require a state to submit a new
attainment plan to achieve annual
reductions ‘‘from the date of such
submission until attainment.’’ The 2018
175 Id.
at D–127.
and SJVUAPCD, ‘‘2016 Ozone Plan for
2008 8-Hour Ozone Standard’’ (adopted June 16,
176 Id.
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PM2.5 Plan was not submitted until May
10, 2019. However, the Serious area
attainment deadline for the San Joaquin
Valley nonattainment area for the 1997
PM2.5 NAAQS was December 31,
2015.178 Accordingly, a plan submittal
2016), Appendix D, Attachment D, tables D–10 to
D–17.
177 85 FR 44192.
178 80 FR 18528.
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to meet the requirements under section
189(d) was due by December 31, 2016,
and reductions were required to occur
as of that date. The decline in emissions
from 2017 to 2020 shows that
reductions did, in fact, occur within the
required timeframe. Furthermore, the
State’s demonstration shows that NOX
emissions reductions from 2017 to 2020
are greater than the required five
percent per year. Thus, the EPA
proposes to find that the SJV PM2.5 Plan
meets the CAA 189(d) requirement to
provide for an annual reduction in PM2.5
or PM2.5 precursor emissions of not less
than five percent of the amount of such
emissions reported in the most recent
inventory prepared for the area.
D. Attainment Demonstration and
Modeling
1. Statutory and Regulatory
Requirements
Section 189(b)(1)(A) of the CAA
requires that each Serious area plan
include a demonstration (including air
quality modeling) that the plan provides
for attainment of the PM2.5 NAAQS by
the applicable attainment date. As
discussed in section IV of this proposal,
given that the outermost statutory
Serious area attainment date for the San
Joaquin Valley area (i.e., December 31,
2015) has passed and that the EPA has
already found that the SJV area failed to
attain by that date, the EPA must
evaluate the State’s plan for attainment
by a later attainment date. Given that
the finding of failure to attain triggered
the State’s obligation to submit a new
plan meeting the requirements of
section 189(d), the EPA is evaluating the
SJV PM2.5 Plan in light of the outermost
attainment date required in section
189(d). That section requires that the
attainment date be as expeditious as
practicable, but not later than five years
following the EPA’s finding that the area
failed to attain the NAAQS by the
applicable Serious area attainment date.
In this case, the State projected such
attainment by December 31, 2020, i.e.,
by the relevant statutory date.
The PM2.5 SIP Requirements Rule
explains that the same general
requirements that apply to Moderate
and Serious area plans under CAA
sections 189(a) and 189(b) should apply
to plans developed pursuant to CAA
section 189(d)—i.e., the plan must
include a demonstration (including air
quality modeling) that the control
strategy provides for attainment of the
PM2.5 NAAQS as expeditiously as
practicable.179 For purposes of
determining the attainment date that is
179 40
CFR 51.1011(b)(1); 81 FR 58010, 58102.
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as expeditious as practicable, the state
must conduct future year modeling that
takes into account emissions growth,
known controls (including any controls
that were previously determined to be
RACM/RACT or BACM/BACT), the five
percent per year emissions reductions
required by CAA section 189(d), and
any other emissions controls that are
needed for expeditious attainment of the
NAAQS.
The EPA’s PM2.5 modeling
guidance 180 (‘‘Modeling Guidance’’ and
‘‘Modeling Guidance Update’’)
recommends that a photochemical
model, such as the Comprehensive Air
Quality Model with Extensions (CAMx)
or Community Multiscale Air Quality
Model (CMAQ), be used to simulate a
base case, with meteorological and
emissions inputs reflecting a base case
year, to replicate concentrations
monitored in that year. The model
application to the base year undergoes
a performance evaluation to ensure that
it satisfactorily corroborates the
concentrations monitored in that year.
The model may then be used to simulate
emissions occurring in other years
required for a plan, namely the base
year (which may differ from the base
case year) and future year.181 The
modeled response to the emissions
changes between those years is used to
calculate relative response factors
(RRFs) that are applied to the design
value in the base year to estimate the
projected design value in the future year
for comparison against the NAAQS.
Separate RRFs are estimated for each
chemical species component of PM2.5,
and for each quarter of the year, to
reflect their differing responses to
seasonal meteorological conditions and
emissions. Because each species is
handled separately, before applying an
RRF, the base year design value should
be speciated using available chemical
180 Memorandum dated November 29, 2018, from
Richard Wayland, Air Quality Assessment Division,
Office of Air Quality Planning and Standards, EPA,
to Regional Air Division Directors, EPA, Subject:
‘‘Modeling Guidance for Demonstrating Air Quality
Goals for Ozone, PM2.5, and Regional Haze,’’
(‘‘Modeling Guidance’’), and memorandum dated
June 28, 2011 from Tyler Fox, Air Quality Modeling
Group, Office of Air Quality Planning and
Standards, EPA, to Regional Air Program Managers,
EPA, Subject: ‘‘Update to the 24 Hour PM2.5
NAAQS Modeled Attainment Test,’’ (‘‘Modeling
Guidance Update’’).
181 In this section, we use the terms ‘‘base case,’’
‘‘base year’’ or ‘‘baseline,’’ and ‘‘future year’’ as
described in section 2.3 of the EPA’s Modeling
Guidance. The ‘‘base case’’ modeling simulates
measured concentrations for a given time period,
using emissions and meteorology for that same year.
The modeling ‘‘base year’’ (which can be the same
as the base case year) is the emissions starting point
for the plan and for projections to the future year,
both of which are modeled for the attainment
demonstration. Modeling Guidance, 37–38.
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species measurements—that is, each
day’s measured PM2.5 design value must
be split into its species components.
The Modeling Guidance provides
additional detail on the recommended
approach.182
2. Summary of the State’s Submission
As discussed in section IV.C, the SJV
PM2.5 Plan includes a modeled
demonstration projecting that the San
Joaquin Valley would attain the 1997
24-hour PM2.5 NAAQS by December 31,
2020, based on ongoing emissions
reductions from baseline control
measures. CARB conducted
photochemical modeling with the
CMAQ model using inputs developed
from routinely available meteorological
and air quality data, as well as more
detailed and extensive data from the
DISCOVER–AQ field study conducted
in January and February of 2013.183 The
Plan’s primary discussion of the
photochemical modeling appears in
Appendix K (‘‘Modeling Attainment
Demonstration’’) of the 2018 PM2.5 Plan.
The State briefly summarizes the area’s
air quality problem in Chapter 2 (‘‘Air
Quality Challenges and Trends’’) and
the modeling results in Chapter 5.3
(‘‘Attainment Demonstration and
Modeling’’) of the 2018 PM2.5 Plan. The
State provides a conceptual model of
PM2.5 formation in the San Joaquin
Valley as part of the modeling protocol
in Appendix L (‘‘Modeling Protocol’’).
Appendix J (‘‘Modeling Emission
Inventory’’) describes emissions input
preparation procedures. The State
presents additional relevant information
in Appendix C (‘‘Weight of Evidence
Analysis’’) of the CARB Staff Report,
which includes ambient trends and
other data in support of the attainment
demonstration.
CARB’s air quality modeling approach
investigated the many inter-connected
facets of modeling ambient PM2.5 in the
San Joaquin Valley, including model
input preparation, model performance
evaluation, use of the model output for
the numerical NAAQS attainment test,
and modeling documentation.
Specifically, this required the
development and evaluation of a
conceptual model, modeling protocol,
episode (i.e., base year) selection,
modeling domain, CMAQ model
selection, initial and boundary
condition procedures, meteorological
182 Modeling Guidance, section 4.5, ‘‘What is the
Recommended Modeled Attainment Test for the 24Hour NAAQS.’’
183 NASA, ‘‘Deriving Information on Surface
conditions from COlumn and VERtically Resolved
Observations Relevant to Air Quality,’’ available at
https://www.nasa.gov/mission_pages/discover-aq/
index.html.
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model choice and performance,
modeling emissions inventory
preparation procedures, model
performance, attainment test procedure,
adjustments to baseline air quality for
modeling, the 2020 attainment test, and
an unmonitored area analysis. CARB’s
supplemental weight of evidence
analysis further supports the Plan’s
demonstration of attainment by the end
of 2020. These analyses are generally
consistent with the EPA’s
recommendations in the Modeling
Guidance.
The model performance evaluation in
Appendix K includes statistical and
graphical measures of model
performance. The magnitude and timing
of predicted concentrations of total
PM2.5, as well as of its ammonium and
nitrate components, generally match the
occurrence of elevated PM2.5 levels in
the measured observations. A
comparison to other recent modeling
efforts shows good model performance
on bias, error, and correlation with
measurements, for total PM2.5 and for
most of its chemical components. The
Weight of Evidence Analysis shows the
downward trend in NOX emissions
along with a 70 percent decrease
between 1999 and 2017 in the number
of days above the 1997 24-hour PM2.5
NAAQS.184 The analysis also shows
decreases in daily PM2.5 concentrations
during winter, and in the frequency of
high PM2.5 concentrations generally.185
Available ambient air quality data show
that total PM2.5 and ammonium nitrate
concentrations have declined over the
2004–2017 period, despite some
increases from time to time.186 These
trends show that there has been an
improvement in air quality due to
emissions reductions in the San Joaquin
Valley, although that point is not fully
reflected in the 98th percentile statistic,
which is the basis for the regulatory
design value.
The State conducted three CMAQ 187
simulations: (1) A 2013 base year
simulation to demonstrate that the
model reasonably reproduced the
observed PM2.5 concentrations in the
San Joaquin Valley; (2) a 2013 baseline
year simulation that was the same as the
2013 base year simulation but excluded
exceptional event emissions, such as
wildfire emissions; and (3) a 2020 future
year simulation that reflects projected
emissions growth and reductions due to
controls that have already been adopted
and implemented.188
Table 4 shows the 2013 base year and
2020 projected future year 24-hour
PM2.5 design values at monitoring sites
in the San Joaquin Valley. As
recommended by the EPA’s guidance,
the 2013 base year design value for
modeling purposes is a weighted
average of three monitored design
values, to minimize the influence of
year-to-year variability. The highest
2020 projected design value is 47.6 mg/
m3 at the Bakersfield–California
monitoring site, which is below the 65
mg/m3 level of the 1997 24-hour PM2.5
NAAQS.
TABLE 4—PROJECTED FUTURE 24-HOUR PM2.5 DESIGN VALUES AT MONITORING SITES IN THE SAN JOAQUIN VALLEY (μg/
m 3)
2013 Base
design value
Monitoring site
Bakersfield—California ............................................................................................................................................
Fresno-Garland ........................................................................................................................................................
Hanford ....................................................................................................................................................................
Fresno-Hamilton & Winery ......................................................................................................................................
Clovis .......................................................................................................................................................................
Visalia ......................................................................................................................................................................
Bakersfield-Planz .....................................................................................................................................................
Madera .....................................................................................................................................................................
Turlock .....................................................................................................................................................................
Modesto ...................................................................................................................................................................
Merced-M. Street .....................................................................................................................................................
Stockton ...................................................................................................................................................................
Merced-S Coffee ......................................................................................................................................................
Manteca ...................................................................................................................................................................
Tranquility ................................................................................................................................................................
64.1
60.0
60.0
59.3
55.8
55.5
55.5
51.0
50.7
47.9
46.9
42.0
41.1
36.9
29.5
2020
Projected
design value
47.6
44.3
43.7
45.6
41.1
42.8
41.2
38.9
37.8
35.8
32.9
33.5
30.0
30.1
21.5
Source: 2018 PM2.5 Plan, Table 5–5.
3. The EPA’s Review of the State’s
Submission
The EPA must make several findings
in order to approve the modeled
attainment demonstration in an
attainment plan SIP submission. First,
we must find that the attainment
demonstration’s technical bases,
including the emissions inventories and
air quality modeling, are adequate. As
discussed in section IV.A of this
preamble, we are proposing to approve
the emissions inventories on which the
SJV PM2.5 Plan’s attainment
demonstration and related provisions
184 Weight of Evidence Analysis, 27–28, Figure
14, and Figure 24.
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are based. Furthermore, the EPA has
evaluated the State’s choice of model
and the extensive discussion in the
Modeling Protocol about modeling
procedures, tests, and performance
analyses. We find that the analyses are
consistent with the EPA’s guidance on
modeling for PM2.5 attainment planning
purposes. Based on these reviews, we
find that the modeling in the Plan is
adequate for the purposes of supporting
the RFP demonstration and
demonstration of attainment by 2020
and are proposing to approve the air
185 Id.
186 Id.
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quality modeling. For further detail, see
the EPA’s February 2020 Modeling TSD.
Second, we must find that the SIP
submittal provides for expeditious
attainment through the timely
implementation of the control strategy.
As discussed in section IV.C of this
preamble, we are proposing to approve
the control strategy in the SJV PM2.5
Plan, including the BACM/BACT
demonstration and the five percent
emissions reduction requirement under
CAA sections 189(b)(1)(B) and 189(d),
respectively.
187 CMAQ
188 2018
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Third, the EPA must find that the
emissions reductions that are relied on
for attainment in the SIP submission are
creditable. As discussed in section
IV.C.2.a, the SJV PM2.5 Plan relies
principally on rules that have already
been adopted and approved by the EPA
to achieve the emissions reductions
needed to attain the 1997 24-hour PM2.5
NAAQS in the San Joaquin Valley. We
present our evaluation of the rules in
section IV.C.2.a and in sections II and III
of the EPA’s 1997 24-hour PM2.5 TSD.
We find that all but two of these rules
are SIP-creditable and that the total
emissions reductions attributed to the
two measures that are not SIP-creditable
have de minimis impacts on the
attainment demonstration in the Plan.
The EPA has also reviewed ambient
monitoring data recorded at air quality
monitors throughout the San Joaquin
Valley PM2.5 nonattainment area during
the three years leading up to the
projected December 31, 2020 attainment
date (i.e., 2018–2020). As discussed in
section V of this proposal, based on
these data, we are proposing to find that
the San Joaquin Valley area attained the
1997 24-hour PM2.5 NAAQS by the
December 31, 2020 attainment date.
Based on these evaluations, we
propose to determine that the SJV PM2.5
Plan provides for attainment of the 1997
24-hour PM2.5 NAAQS by the most
expeditious date practicable, consistent
with the requirements of CAA section
189(d). Furthermore, because the 2015
Serious area attainment date has passed,
and the EPA found that the area failed
to attain by the Serious area attainment
date, we are evaluating the State’s
compliance with the Serious area plan
requirements in light of the attainment
date required under CAA section
189(d).189 Thus, we are also proposing
to determine that the Plan meets the
Serious area attainment plan
requirement under CAA section
189(b)(1)(A).
E. Reasonable Further Progress and
Quantitative Milestones
1. Statutory and Regulatory
Requirements
CAA section 172(c)(2) provides that
all nonattainment area plans shall
require RFP toward attainment. In
addition, CAA section 189(c) requires
that all PM2.5 nonattainment area SIPs
include quantitative milestones to be
achieved every three years until the area
is redesignated to attainment and that
demonstrate RFP. Section 171(l) of the
Act defines RFP as ‘‘such annual
incremental reductions in emissions of
the relevant air pollutant as are required
by [Part D] or may reasonably be
required by the Administrator for the
purpose of ensuring attainment of the
applicable [NAAQS] by the applicable
date.’’ Neither subpart 1 nor subpart 4
of part D, title I of the Act requires that
states achieve a set percentage of
emissions reductions in any given year
for purposes of satisfying the RFP
requirement. For purposes of the PM2.5
NAAQS, the EPA has interpreted the
RFP requirement to require that the
nonattainment area plans show annual
incremental emissions reductions
sufficient to maintain generally linear
progress toward attainment by the
applicable deadline.190
Attainment plans for PM2.5
nonattainment areas should include
detailed schedules for compliance with
emissions regulations in the area and
provide corresponding annual
emissions reductions to be achieved by
each milestone in the schedule.191 In
reviewing an attainment plan under
subpart 4, the EPA considers whether
the annual incremental emissions
reductions to be achieved are reasonable
in light of the statutory objective of
timely attainment. Although early
implementation of the most costeffective control measures is often
appropriate, states should consider both
cost-effectiveness and pollution
reduction effectiveness when
developing implementation schedules
for control measures and may
implement measures that are more
effective at reducing PM2.5 earlier to
provide greater public health
benefits.192
The PM2.5 SIP Requirements Rule
establishes specific regulatory
requirements for purposes of satisfying
the Act’s RFP requirements and
provides related guidance in the
preamble to the rule. Specifically, under
the PM2.5 SIP Requirements Rule, each
PM2.5 attainment plan must contain an
RFP analysis that includes, at minimum,
the following four components: (1) An
implementation schedule for control
measures; (2) RFP projected emissions
for direct PM2.5 and all PM2.5 plan
precursors for each applicable milestone
year, based on the anticipated control
measure implementation schedule; (3) a
demonstration that the control strategy
and implementation schedule will
achieve reasonable progress toward
attainment between the base year and
the attainment year; and (4) a
demonstration that by the end of the
calendar year for each milestone date for
190 General
191 Id.
189 See
CAA section 179(d); 40 CFR 51.1004(a)(3).
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Preamble Addendum, 42015.
at 42016.
the area, pollutant emissions will be at
levels that reflect either generally linear
progress or stepwise progress in
reducing emissions on an annual basis
between the base year and the
attainment year.193 Additionally, states
should estimate the RFP projected
emissions for each quantitative
milestone year by sector on a pollutantby-pollutant basis.194
Section 189(c) of the Act requires that
PM2.5 attainment plans include
quantitative milestones that
demonstrate RFP. The purpose of the
quantitative milestones is to allow
periodic evaluation of the area’s
progress towards attainment of the
NAAQS consistent with RFP
requirements. Because RFP is an annual
emissions reduction requirement and
the quantitative milestones are to be
achieved every three years, when a state
demonstrates compliance with the
quantitative milestone requirement, it
should also demonstrate that RFP has
been achieved during each of the
relevant three years. Quantitative
milestones should provide an objective
means to evaluate progress toward
attainment meaningfully, e.g., through
imposition of emissions controls in the
attainment plan and the requirement to
quantify those required emissions
reductions. The CAA also requires states
to submit milestone reports (due 90
days after each milestone), and these
reports should include calculations and
any assumptions made by the state
concerning how RFP has been met, e.g.,
through quantification of emissions
reductions to date.195
The CAA does not specify the starting
point for counting the three-year periods
for quantitative milestones under CAA
section 189(c). In the General Preamble
and General Preamble Addendum, the
EPA interpreted the CAA to require that
the starting point for the first three-year
period be the due date for the Moderate
area plan submission.196 In keeping
with this historical approach, the EPA
established December 31, 2014, the
deadline that the EPA established for a
state’s submission of any additional
attainment-related SIP elements
necessary to satisfy the subpart 4
Moderate area requirements for the 1997
PM2.5 NAAQS, as the starting point for
the first three-year period under CAA
section 189(c) for the 1997 PM2.5
NAAQS in the San Joaquin Valley.197
193 40
CFR 51.1012(a).
FR 58010, 58056.
195 General Preamble Addendum, 42016–42017.
196 General Preamble, 13539, and General
Preamble Addendum, 42016.
197 79 FR 31566 (final rule establishing subpart 4
moderate area classifications and deadline for
194 81
192 Id.
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Under the PM2.5 SIP Requirements
Rule, each attainment plan submission
for an area designated nonattainment for
the 1997 PM2.5 NAAQS before January
15, 2015, must contain quantitative
milestones to be achieved no later than
three years after December 31, 2014, and
every three years thereafter until the
milestone date that falls within three
years after the applicable attainment
date.198 If the area fails to attain, this
post-attainment date milestone provides
the EPA with the tools necessary to
monitor the area’s continued progress
toward attainment while the state
develops a new attainment plan.199
Quantitative milestones must provide
for objective evaluation of RFP toward
timely attainment of the PM2.5 NAAQS
in the area and include, at minimum, a
metric for tracking progress achieved in
implementing SIP control measures,
including BACM and BACT, by each
milestone date.200
Because the EPA designated the San
Joaquin Valley area as nonattainment for
the 1997 24-hour PM2.5 NAAQS
effective April 5, 2005,201 the plan for
this area must contain quantitative
milestones to be achieved no later than
three years after December 31, 2014 (i.e.,
by December 31, 2017), and every three
years thereafter until the milestone date
that falls within three years after the
applicable attainment date.202 For a
Serious area attainment plan with a
statutory attainment date of December
31, 2015, the relevant quantitative
milestone year is December 31, 2017.
However, as discussed in section III, the
area did not attain by the statutory
Serious area attainment date and
evaluating reasonable further progress
toward that date does not make sense.
We are therefore evaluating the Serious
area obligations based on the attainment
date the State must meet in a plan
required under CAA section 189(d).203
To meet CAA section 189(d), the SJV
PM2.5 Plan includes a demonstration
that the area will attain by December 31,
2020. Therefore, in accordance with 40
CFR 51.1013(a)(4), the attainment plan
for this area must contain quantitative
related SIP submissions). Although this final rule
did not affect any action that the EPA had
previously taken under CAA section 110(k) on a SIP
for a PM2.5 nonattainment area, the EPA noted that
states may need to submit additional SIP elements
to fully comply with the applicable requirements of
subpart 4, even for areas with previously approved
PM2.5 attainment plans, and that the deadline for
any such additional plan submissions was
December 31, 2014. Id. at 31569.
198 40 CFR 51.1013(a)(4).
199 81 FR 58010, 58064.
200 Id. at 58064 and 58092.
201 70 FR 944.
202 40 CFR 51.1013(a)(4).
203 See CAA section 179(d); 40 CFR 51.1004(a)(3).
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H–2 in Appendix H contains an
anticipated implementation schedule
for District regulatory control measures
and Table 4–8 in Chapter 4 of the 2018
2. Summary of the State’s Submission
PM2.5 Plan contains an anticipated
Appendix H (‘‘RFP, Quantitative
implementation schedule for CARB
Milestones, and Contingency’’) of the
control measures in the San Joaquin
2018 PM2.5 Plan contains the State’s RFP Valley. Table H–5 in Appendix H
demonstration and quantitative
contains projected emissions for each
milestones for the 1997 24-hour PM2.5
quantitative milestone year. These
NAAQS,204 and the Valley State SIP
emissions levels reflect baseline
Strategy contains the control measure
emissions projections through the 2023
commitments that CARB has identified
post-attainment milestone year.208
The SJV PM2.5 Plan identifies
as mobile source quantitative milestones
emissions reductions needed for
for the 2020 milestone date.205 Given
attainment of the 1997 24-hour PM2.5
the State’s conclusions that ammonia,
NAAQS by 2020,209 and identifies San
SOX, and VOC emissions do not
Joaquin Valley’s progress toward
contribute significantly to PM2.5 levels
attainment in each milestone year.210
that exceed the 1997 24-hour PM2.5
The State and District set RFP targets for
NAAQS in the San Joaquin Valley, as
each of the quantitative milestone years
discussed in section IV.B of this
as shown in Table H–8 of Appendix H
proposed rule, the RFP demonstration
of the 2018 PM2.5 Plan.
provided by the State addresses
According to the Plan, reductions in
emissions of direct PM2.5 and NOX.206
both direct PM2.5 and NOX emissions
Similarly, the State developed
from 2013 base year levels result in
quantitative milestones based upon
emissions levels consistent with
implementation of control strategy
attainment in the 2020 attainment year.
measures in the adopted SIP and in the
Based on these analyses, the State and
SJV PM2.5 Plan that achieve reductions
in emissions of direct PM2.5 and NOX.207 District conclude that the adopted
For the 1997 24-hour PM2.5 NAAQS, the control strategy is adequate to meet the
RFP requirement for the 1997 24-hour
RFP analysis in the Plan shows
PM2.5 NAAQS.
generally linear progress toward
attainment.
Quantitative Milestones
We describe the RFP analysis and
Appendix H of the 2018 PM2.5 Plan
quantitative milestones in the SJV PM2.5
identifies
the milestone dates of
Plan in greater detail below.
December 31, 2017, December 31, 2020,
Reasonable Further Progress
and December 31, 2023, for the 1997
PM2.5 NAAQS.211 Appendix H also
The State addresses the RFP and
identifies target emissions levels to meet
quantitative milestone requirements in
the RFP requirement for direct PM2.5
Appendix H to the 2018 PM2.5 Plan
and NOX emissions for each of these
submitted in February 2020. The State
milestone
years,212 and State and
estimates that emissions of direct PM2.5
District
control
measures that will
and NOX will generally decline from the
achieve
emissions
reductions in the
2013 base year to the projected 2020
attainment year, and beyond to the 2023 years leading up to each of the
milestones, in accordance with the
post-attainment quantitative milestone
control strategy in the Plan.213
year. The Plan’s emissions inventory
The Plan includes quantitative
shows that direct PM2.5 and NOX are
milestones for mobile, stationary, and
emitted by a large number and range of
sources in the San Joaquin Valley. Table area sources. For mobile sources, CARB
has developed quantitative milestones
that provide for an evaluation of RFP
204 As discussed in footnote 34, all references to
based on the implementation of specific
Appendix H in this proposed rule are to the revised
control measures by the relevant threeversion submitted on February 11, 2020, which
replaces the version submitted with the 2018 PM2.5
year milestones. For each quantitative
Plan on May 10, 2019.
milestone year, the Plan provides for
205 Valley State SIP Strategy, Table 7 (identifying
evaluating RFP by tracking State and
State measures scheduled for action between 2017
District implementation of regulatory
and 2020, inter alia) and CARB Resolution 18–49,
‘‘San Joaquin Valley Supplement to the 2016 State
measures and SIP commitments during
Strategy for the State Implementation Plan’’
the three-year period leading to each
milestones to be achieved no later than
December 31, 2017, December 31, 2020,
and December 31, 2023.
(October 25, 2018), 5 (adopting State commitment
to begin public processes and propose for Board
consideration the list of proposed SIP measures
outlined in the Valley State SIP Strategy and
included in Attachment A, according to the
schedule set forth therein).
206 SJV PM
2.5 Plan, Appendix H, H–1.
207 Id. at H–18 and H–19 (District milestones) and
H–21 and H–22 (State milestones).
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208 Id.
at tables H–3 to H–5.
at Table H–6.
210 Id. at Table H–7.
211 Id. at Table H–12.
212 Id. at Table H–8.
213 Id. at H–18 and H–19 (District milestones) and
H–21 and H–22 (State milestones).
209 Id.
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milestone date, consistent with the
control strategy in the SJV PM2.5
Plan.214 The identified regulatory
measures include State measures for
light-duty vehicles and non-road
vehicles and several District measures
for stationary and area sources.215
CARB submitted its 2017 Quantitative
Milestone Report for the San Joaquin
Valley to the EPA on December 20,
2018.216 The report includes a
certification that CARB and the District
met the 2017 quantitative milestones
identified in the SJV PM2.5 Plan for the
1997 PM2.5 NAAQS and discusses the
State’s and District’s progress on
implementing the three CARB measures
and six District measures identified in
Appendix H as quantitative milestones
for the 2017 milestone year. On
February 15, 2021, the EPA determined
that the 2017 Quantitative Milestone
Report was adequate.217 In our
evaluation of the 2017 Quantitative
Milestone Report, we found that the
control measures in the Plan are in
effect, consistent with the RFP
demonstration in the SJV PM2.5 Plan for
the 1997 24-hour PM2.5 NAAQS, but we
noted that the determination of
adequacy did not constitute approval of
any component of the SJV PM2.5 Plan.218
3. The EPA’s Review of the State’s
Submission
The RFP demonstration in the SJV
PM2.5 Plan identifies quantitative
milestone dates (i.e., December 31 of
2017, 2020, and 2023) that are
consistent with the requirements of 40
CFR 51.1013(a)(4) and presents
projected RFP emissions levels for
direct PM2.5 and NOX to be achieved by
these milestone dates based on the
implementation schedule for existing
control measures in the area (i.e.,
baseline measures). The projected
emissions levels based on the
implementation schedule in the Plan
214 Id. We note that the District’s identified
quantitative milestones for 2023 appear to contain
a typographical error, as they include a District
report on ‘‘[t]he status of SIP measures adopted
between 2017 and 2020 as per the schedule
included in the adopted Plan.’’ Id. at H–18 and H–
19. We understand that the District intended to
refer here to the status of SIP measures adopted
between 2020 and 2023, consistent with the
schedule in the 2018 PM2.5 Plan.
215 Id. at H–18 and H–19 (District milestones),
and H–21 and H–22 (State milestones).
216 Letter dated December 20, 2018, from Richard
W. Corey, Executive Officer, CARB, to Michael
Stoker, Regional Administrator, EPA Region IX,
with attachment ‘‘2017 Quantitative Milestone
Report for the 1997 and 2006 NAAQS.’’
217 Letter dated February 15, 2021, from Deborah
Jordan, Acting Regional Administrator, EPA Region
IX, to Richard W. Corey, Executive Officer, CARB,
with enclosure titled ‘‘EPA Evaluation of 2017
Quantitative Milestone Report.’’
218 Id.
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demonstrate that the control strategy
will achieve direct PM2.5 and NOX
emissions reductions at rates
representing generally linear progress
towards attainment between the 2013
baseline year and the 2020 attainment
year. The target emissions levels and
associated control requirements provide
for objective evaluation of the area’s
progress towards attainment of the 1997
24-hour PM2.5 NAAQS.
The State’s quantitative milestones in
Appendix H are to implement specific
measures listed in the State’s control
measure commitments that apply to
heavy-duty trucks and buses, light-duty
vehicles, and non-road equipment
sources and may provide substantial
reductions in emissions of direct PM2.5
and NOX from mobile sources in the San
Joaquin Valley. Similarly, the District’s
quantitative milestones in Appendix H
are to implement specific measures
listed in the District’s control measure
commitments that apply to sources such
as residential wood burning,
commercial charbroiling, glass melting
furnaces, and internal combustion
engines, and that may provide
substantial reductions in emissions of
direct PM2.5 and NOX from stationary
sources. These milestones provide an
objective means for tracking the State’s
and District’s progress in implementing
their respective control strategies and,
thus, provide for objective evaluation of
the San Joaquin Valley’s progress
toward timely attainment.
For these reasons, we propose to
determine that the SJV PM2.5 Plan
satisfies the requirements for RFP in
CAA section 172(c)(2) and 40 CFR
51.1012 and for quantitative milestones
in CAA section 189(c) and 40 CFR
51.1013 for the 1997 24-hour PM2.5
NAAQS in the San Joaquin Valley for
purposes of both the Serious area and
CAA section 189(d) attainment plans.
Because we are proposing to determine
that the San Joaquin Valley has attained
the 1997 24-hour PM2.5 NAAQS by the
December 31, 2020 attainment date, as
discussed in section V of this proposed
rule, we are also proposing to determine
that the requirement for a postattainment milestone will no longer
apply in the San Joaquin Valley
nonattainment area for these NAAQS.
As described in section IV.E.1 above,
the purpose of the post-attainment
quantitative milestone is to provide the
EPA with the tools necessary to monitor
the area’s continued progress toward
attainment in the event the area fails to
attain by the attainment date.219 Once
an area has attained the NAAQS, ‘‘no
further milestones are necessary or
meaningful.’’ 220 Similarly, the section
189(c)(2) requirement to submit a
quantitative milestone report no longer
applies when the area has attained the
standard.221 Accordingly, upon a final
determination that the San Joaquin
Valley area has attained the 1997 24hour PM2.5 NAAQS by the attainment
date, the post-attainment RFP milestone
will no longer have purpose and the
EPA is proposing to find that the
requirement will no longer apply to the
San Joaquin Valley. If we finalize this
action as proposed, the State will no
longer be required to submit a
quantitative milestone report for the San
Joaquin Valley under 40 CFR 51.1013(b)
for the purposes of the 2023 postattainment milestone year identified in
the Plan for the 1997 24-hour PM2.5
NAAQS.
F. Contingency Measures
1. Requirements for Contingency
Measures
Under CAA section 172(c)(9), each
state required to make a nonattainment
plan SIP submission must include, in
such plan, contingency measures to be
implemented if an area fails to meet RFP
(‘‘RFP contingency measures’’) or fails
to attain the NAAQS by the applicable
attainment date (‘‘attainment
contingency measures’’). Under the
PM2.5 SIP Requirements Rule, states
must include contingency measures that
will be implemented following a
determination by the EPA that the state
has failed: (1) To meet any RFP
requirement in the approved SIP; (2) to
meet any quantitative milestone in the
approved SIP; (3) to submit a required
quantitative milestone report; or (4) to
attain the applicable PM2.5 NAAQS by
the applicable attainment date.222
Contingency measures must be fully
adopted rules or control measures that
are ready to be implemented quickly
upon failure to meet RFP or failure of
the area to meet the relevant NAAQS by
the applicable attainment date.223
The purpose of contingency measures
is to continue progress in reducing
emissions while a state revises its SIP to
meet the missed RFP requirement or to
correct ongoing nonattainment. Neither
the CAA nor the EPA’s implementing
regulations establish a specific level of
emissions reductions that
implementation of contingency
measures must achieve, but the EPA
recommends that contingency measures
provide for emissions reductions
220 75
FR 13710, 13713 (March 23, 2010).
221 Id.
222 40
CFR 51.1014(a).
FR 58010, 58066 and General Preamble
Addendum, 42015.
223 81
219 81
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equivalent to approximately one year of
reductions needed for RFP in the
nonattainment area at issue, calculated
as the overall level of reductions needed
to demonstrate attainment divided by
the number of years from the base year
to the attainment year. In general, we
expect all actions needed to effect full
implementation of the measures to
occur within 60 days after the EPA
notifies the state of a failure to meet RFP
or to attain.224
To satisfy the requirements of 40 CFR
51.1014, the contingency measures
adopted as part of a PM2.5 attainment
plan must consist of control measures
for the area that are not otherwise
required to meet other nonattainment
plan requirements (e.g., to meet RACM/
RACT requirements) and must specify
the timeframe within which their
requirements become effective following
any of the EPA determinations specified
in 40 CFR 51.1014(a). In a 2016 decision
called Bahr v. EPA (‘‘Bahr’’),225 the
Ninth Circuit Court of Appeals rejected
the EPA’s interpretation of CAA section
172(c)(9) to allow approval of alreadyimplemented control measures as
contingency measures. In Bahr, the
Ninth Circuit concluded that
contingency measures must be measures
that are triggered and implemented only
after the EPA determines that an area
failed to meet RFP requirements or to
attain by the applicable attainment date.
Thus, within the geographic jurisdiction
of the Ninth Circuit, already
implemented measures cannot serve as
contingency measures under CAA
section 172(c)(9).226 To comply with
section 172(c)(9), a state must develop,
adopt, and submit a contingency
measure to be triggered upon a failure
to meet an RFP milestone, failure to
meet a quantitative milestone
requirement, or failure to attain the
NAAQS by the applicable attainment
date.
2. Summary of the State’s Submission
The SJV PM2.5 Plan addresses the
contingency measure requirement for
the 1997 24-hour PM2.5 NAAQS in
section 5.6 and Appendix H
(specifically, section H.3 (‘‘Contingency
Measures’’)) of the 2018 PM2.5 Plan. The
Plan relies on revisions to the District’s
wood-burning rule (Rule 4901) and
refers to a SIP revision submitted by
CARB on October 23, 2017, titled ‘‘State
224 81 FR 58010, 58066. See also General
Preamble, 13512, 13543–13544, and General
Preamble Addendum, 42014–42015.
225 Bahr v. EPA, 836 F.3d 1218, 1235–1237 (9th
Cir. 2016).
226 See also Sierra Club v. EPA, 985 F.3d 1055
(D.C. Cir. 2021) and Assoc. of Irritated Residents v.
EPA, No. 19–71223, slip op. (9th Cir. Aug 26, 2021).
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Implementation Plan Attainment
Contingency Measures for the San
Joaquin Valley 15 mg/m3 Annual PM2.5
NAAQS’’ (‘‘2017 Contingency Measure
SIP’’).227 On March 19, 2021, CARB
withdrew the 2017 Contingency
Measure SIP submission.228 Therefore,
we are not evaluating the 2017
Contingency Measure SIP as part of this
action.
With respect to the District
contingency measure, the 2018 PM2.5
Plan states that the District will amend
Rule 4901 to include a requirement that
would be triggered upon a
determination by the EPA that the San
Joaquin Valley failed to meet a
regulatory requirement necessitating
implementation of a contingency
measure.229 The District adopted
amendments to Rule 4901 on June 20,
2019, including a contingency measure
in section 5.7.3 of the amended rule
(more details below). In the EPA’s July
22, 2020 final action to approve Rule
4901, as amended June 20, 2019, we did
not evaluate section 5.7.3 of the
amended rule for compliance with CAA
requirements for contingency
measures.230 On July 22, 2021, the EPA
proposed to find that the contingency
provision of Rule 4901 (section 5.7.3)
does not satisfy the CAA requirements
for contingency measures for the 1997
annual PM2.5 NAAQS and proposed to
remove the provision from the SIP
because it is severable from the
remainder of Rule 4901.231 In this
action, we evaluate section 5.7.3 of Rule
4901 for compliance with the
contingency measures requirements for
purposes of the 1997 24-hour PM2.5
NAAQS.
Rule 4901 is designed to limit
emissions generated by the use of wood
burning fireplaces, wood burning
heaters, and outdoor wood burning
devices. The rule establishes
requirements for the sale/transfer,
operation, and installation of wood
burning devices and for advertising the
sale of seasoned wood consistent with a
moisture content limit within the San
Joaquin Valley. The rule includes a twotiered, episodic wood burning
curtailment requirement that applies
during four winter months, November
227 Letter dated October 23, 2017, from Richard
W. Corey, Executive Officer, CARB, to Alexis
Strauss, Acting Regional Administrator, EPA Region
9.
228 Letter dated March 19, 2021, from Richard W.
Corey, Executive Officer, CARB, to Deborah Jordan,
Acting Regional Administrator, EPA Region 9,
transmitting CARB Executive Order S–21–004.
229 2018 PM
2.5 Plan, Appendix H, H–25.
230 85 FR 44206 (final approval of Rule 4901); 85
FR 1131, 1132–1133 (January 9, 2020) (proposed
approval of Rule 4901).
231 86 FR 38652.
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through February. During a level one
episodic wood burning curtailment,
section 5.7.1 prohibits any person from
operating a wood burning fireplace or
unregistered wood burning heater, but
permits the use of a properly operated
wood burning heater that meets
certification requirements and has a
current registration with the District.
Sections 5.9 through 5.11 impose
specific registration requirements on
any person operating a wood burning
fireplace or wood burning heater and
section 5.12 imposes specific
certification requirements on wood
burning heater professionals. During a
level two episodic wood burning
curtailment, operation of any wood
burning device is prohibited by section
5.7.2.
Prior to the 2019–2020 wood burning
season, the District imposed a level one
curtailment when the PM2.5
concentration was forecasted to be
between 20 mg/m3 and 65 mg/m3 and
imposed a level two curtailment when
the PM2.5 concentration was forecasted
to be above 65 mg/m3 or the PM10
concentration was forecasted to be
above 135 mg/m3. In 2019 the District
adopted revisions to Rule 4901 to lower
the wood burning curtailment
thresholds in the ‘‘hot spot’’ counties of
Madera, Fresno, and Kern. The District
lowered the level one PM2.5 threshold
for these three counties from 20 mg/m3
to 12 mg/m3, and the level two PM2.5
threshold from 65 mg/m3 to 35 mg/m3.
The District did not modify the
curtailment thresholds for other
counties in the San Joaquin Valley—
those levels remain at 20 mg/m3 for level
one and 65 mg/m3 for level two.
The District’s 2019 revision to Rule
4901 also included the addition of a
contingency measure in section 5.7.3 of
the rule, requiring that 60 days
following the effective date of an EPA
determination that the San Joaquin
Valley has failed to attain the 1997,
2006, or 2012 PM2.5 NAAQS by the
applicable attainment date, the PM2.5
curtailment levels of any county that
has failed to attain the applicable
standard will be lowered to the
curtailment levels in place for hot spot
counties. The District estimates that the
potential emissions reduction of direct
PM2.5 would be in the range of 0.014 tpd
(if the contingency measure is triggered
in Kings County but not the other nonhot spot counties) to 0.387 tpd (if the
contingency measure is triggered in all
five of the non-hot spot counties), but
there would be no emissions reduction
if, at the time of the determination of
failure to attain the 1997 24-hour PM2.5
NAAQS by the attainment date,
violations of the 1997 24-hour PM2.5
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NAAQS are observed only at monitors
in the hot spot counties.232 The
corresponding potential NOX emissions
reduction would be in the range of 0.002
tpd to 0.060 tpd, respectively, but once
again, there would be no emissions
reduction if the violations are monitored
in the hot spot counties only.233 The
EPA has already approved Rule 4901, as
amended in 2019, as a revision to the
California SIP.234
Valley nonattainment area for the 1997
24-hour PM2.5 NAAQS, for the reasons
discussed below.
Attainment contingency measures
under 172(c)(9) are triggered upon the
EPA’s determination that an area failed
to attain a given NAAQS by its
applicable attainment date. CAA section
179(c) requires the EPA to determine
whether the area attained the NAAQS
by its applicable attainment date. As
part of this proposed action, we are
3. The EPA’s Review of the State’s
proposing to determine that the San
Submission
Joaquin Valley nonattainment area
As noted above, the EPA previously
attained the 1997 24-hour PM2.5 NAAQS
proposed to find that the contingency
by the December 31, 2020 attainment
provision of Rule 4901 (section 5.7.3)
date projected by the Plan. Based on our
does not satisfy the CAA requirements
proposed finding of attainment by the
for contingency measures for the 1997
applicable attainment date, we are also
annual PM2.5 NAAQS.235 As part of that proposing to determine that the CAA
proposal, the EPA found that the
requirement for the SIP to provide for
measure meets some, but not all, of the
attainment contingency measures will
applicable requirements for contingency no longer apply to the San Joaquin
measures under CAA section 172(c)(9)
Valley for the 1997 24-hour PM2.5
and 40 CFR 51.1014. One of the
NAAQS. Under CAA section 172(c)(9),
deficiencies outlined in our proposal
attainment contingency measures are
was that the contingency provisions of
implemented only if the area fails to
Rule 4901 do not address the potential
attain by the attainment date. Therefore,
for State failures to meet RFP, to meet
if we finalize the determination that the
a quantitative milestone, or to submit a
San Joaquin Valley nonattainment area
quantitative milestone report. In
has attained the 1997 24-hour PM2.5
addition, the contingency measure
NAAQS, attainment contingency
provisions of Rule 4901 are not
measures for this NAAQS would never
structured to achieve any additional
be required to be implemented. Because
emissions reductions if the EPA were to there are no circumstances under which
find that the monitoring locations in the CAA section 172(c)(9) attainment
‘‘hot spot’’ counties (i.e., Fresno, Kern,
contingency measures could ever be
or Madera) are the only counties in the
triggered, we think it is a reasonable
San Joaquin Valley that are violating the interpretation of the CAA that these
1997 24-hour PM2.5 NAAQS as of the
measures are no longer required to be
attainment date. To qualify as a
submitted.236
contingency measure, a measure must
Similarly, we are proposing to find
be structured to achieve emissions
that, upon finalization of the
reductions if triggered; however, the
determination of attainment by the
contingency provisions of Rule 4901
attainment date, the RFP related
provide for such reductions only under
contingency measure requirement (i.e.,
certain circumstances.
for failure to meet RFP, to submit a
Consistent with our proposal for the
quantitative milestone report, or to meet
1997 annual PM2.5 NAAQS and for these the quantitative milestone) would also
same reasons, we are proposing to
no longer apply to the San Joaquin
disapprove the contingency measure
Valley nonattainment area for the 1997
element of the SJV PM2.5 Plan for the
24-hour PM2.5 NAAQS. The purpose of
1997 24-hour PM2.5 NAAQS as not
the RFP and related quantitative
meeting the requirements of 172(c)(9)
milestone requirements under the CAA
and 40 CFR 51.1014 for Serious area and is to ‘‘ensure[e] attainment of the
section 189(d) attainment plans.
applicable [NAAQS] by the applicable
However, the EPA is also proposing to
date.’’ 237 Because the sole purpose of
find that the contingency measures are
RFP contingency measures is to provide
no longer required for the San Joaquin
continued progress if an area fails to
meet its RFP or quantitative milestone
232 See Table B–13 in Appendix B from the
requirements, a final determination of
District’s Final Staff Report (June 20, 2019) for
attainment by the attainment date serves
revisions to Rule 4901.
233 NO emissions reductions from the
as demonstration that RFP requirements
X
contingency measure are based on the District’s
for the area have been met, and that
estimates for direct PM2.5 emissions using the ratio
there is no need for any later
of direct PM2.5 to NOX in Table 1, page 8, of the
District’s Final Staff Report (June 20, 2019) for
revisions to Rule 4901.
234 85 FR 44206.
235 86 FR 38652.
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236 See Bahr v. Regan, No. 20–70092, (9th Cir.
July 28, 2021), slip op. 45–51.
237 CAA section 171(c).
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53175
quantitative milestone or milestone
report, and thus the RFP related
contingency measures are no longer
needed. Accordingly, because we are
proposing to determine that the San
Joaquin Valley has attained the 1997 24hour PM2.5 NAAQS by the December 31,
2020 attainment date, and that therefore
the RFP and quantitative milestone
requirements would no longer apply, we
are now also proposing to determine
that RFP contingency measures are no
longer required for this area.238
Under section 179(a) of the CAA, final
disapproval of a SIP submission that
addresses a requirement of part D, title
I of the CAA, or is required in response
to a finding of substantial inadequacy as
described in CAA section 110(k)(5) (SIP
Call), starts sanctions clocks. The SJV
PM2.5 Plan, including the contingency
measure element, does address
requirements of part D. However, if we
finalize our determinations that the
requirements for contingency measures
no longer apply to the San Joaquin
Valley nonattainment area for the 1997
24-hour PM2.5 NAAQS, then the
contingency measure element of the SJV
PM2.5 Plan would no longer be required
to address any part D requirement for
the 1997 24-hour PM2.5 NAAQS.
Therefore, final disapproval of the
contingency measure element of the SJV
PM2.5 Plan would not trigger sanctions
clocks. Similarly, final disapproval
would not trigger any obligation for the
EPA to promulgate a federal
implementation plan (FIP) under CAA
section 110(c) because there would be
no deficiency for such a FIP to
correct.239
Because we are proposing to approve
the RFP analysis, the modeled
attainment demonstration, and the
motor vehicle emissions budgets, we are
also proposing to issue a protective
finding under 40 CFR 93.120(a)(3) in the
event we finalize the disapproval of the
238 With respect to the 2017 RFP contingency
measure requirement specifically, we note that, as
explained in section IV.E.2 of this proposed rule,
on December 20, 2018, CARB submitted a
quantitative milestone report demonstrating that the
2017 quantitative milestones in the SJV PM2.5 Plan
have been achieved, and the EPA has determined
that this milestone report is adequate. Because the
State and District have demonstrated that the San
Joaquin Valley area has met its 2017 quantitative
milestones, RFP contingency measures for the 2017
milestone year would never be triggered.
239 This is the case for both the Serious area plan
and the section 189(d) plan. Because the purpose
of contingency measures is to ensure continued
progress toward attainment in the event that an area
fails to attain the NAAQS or meet RFP
requirements, and we are proposing to find that the
area has meet the 1997 24-hour PM2.5 NAAQS, there
is no purpose to triggering sanction and FIP
obligations for the State to submit measures to
achieve the goal of attaining the 1997 24-hour PM2.5
NAAQS when this goal has already been met.
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contingency measures. Without a
protective finding, the final disapproval
would result in a conformity freeze,
under which only projects in the first
four years of the most recent conforming
Regional Transportation Plan (RTP) and
Transportation Improvement Programs
(TIPs) can proceed. During a freeze, no
new RTPs, TIPs, or RTP/TIP
amendments can be found to
conform.240 Under this protective
finding, however, the final disapproval
of the contingency measures does not
result in a transportation conformity
freeze in the San Joaquin Valley PM2.5
nonattainment area.
If the State chooses to withdraw the
contingency measure element with
respect to the 1997 24-hour PM2.5
NAAQS prior to our final action on the
SJV PM2.5 Plan for that NAAQS, we
would take no final action either to
approve or to disapprove that element.
G. Motor Vehicle Emission Budgets
1. Statutory and Regulatory
Requirements
Section 176(c) of the CAA requires
federal actions in nonattainment and
maintenance areas to conform to the
goals of the state’s SIP to eliminate or
reduce the severity and number of
violations of the NAAQS and achieve
timely attainment of the NAAQS.
Conformity to the SIP’s goals means that
such actions will not: (1) Cause or
contribute to violations of a NAAQS, (2)
worsen the severity of an existing
violation, or (3) delay timely attainment
of any NAAQS or any interim
milestone.
Actions involving Federal Highway
Administration (FHWA) or Federal
Transit Administration (FTA) funding
or approval are subject to the EPA’s
transportation conformity rule, codified
at 40 CFR part 93, subpart A. Under this
rule, metropolitan planning
organizations (MPOs) in nonattainment
and maintenance areas coordinate with
state and local air quality and
transportation agencies, the EPA, the
FHWA, and the FTA to demonstrate that
an area’s regional transportation plans
(RTPs) and transportation improvement
programs conform to the applicable SIP.
This demonstration is typically done by
showing that estimated emissions from
existing and planned highway and
transit systems are less than or equal to
the motor vehicle emission budgets
(MVEBs or ‘‘budgets’’) contained in all
control strategy SIPs. Budgets are
generally established for specific years
and specific pollutants or precursors
and must reflect all of the motor vehicle
240 40
CFR 93.120(a)(2).
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control measures contained in the
attainment and RFP demonstrations.241
Under the PM2.5 SIP Requirements
Rule, Serious area PM2.5 attainment
plans must include appropriate
quantitative milestones and projected
RFP emissions levels for direct PM2.5
and all PM2.5 plan precursors in each
milestone year.242 For an area
designated nonattainment for the 1997
PM2.5 NAAQS before January 15, 2015,
the attainment plan must contain
quantitative milestones to be achieved
no later than three years after December
31, 2014, and every three years
thereafter until the milestone date that
falls within three years after the
applicable attainment date.243 As the
EPA explained in the preamble to the
PM2.5 SIP Requirements Rule, it is
important to include a post-attainment
year quantitative milestone to ensure
that, if the area fails to attain by the
attainment date, the EPA can continue
to monitor the area’s progress toward
attainment while the state develops a
new attainment plan.244 Although the
post-attainment year quantitative
milestone is a required element of a
Serious area plan, it is not necessary to
demonstrate transportation conformity
for 2023 or to use the 2023 budgets in
transportation conformity
determinations until such time as the
area fails to attain the 1997 24-hour
PM2.5 NAAQS.
PM2.5 plans should identify budgets
for direct PM2.5, NOX, and all other
PM2.5 precursors for which on-road
emissions are determined to
significantly contribute to PM2.5 levels
in the area for each RFP milestone year
and the attainment year, if the plan
demonstrates attainment. All direct
PM2.5 SIP budgets should include direct
PM2.5 motor vehicle emissions from
tailpipes, brake wear, and tire wear.
With respect to PM2.5 from re-entrained
road dust and emissions of VOC, SO2,
and/or ammonia, the transportation
conformity provisions of 40 CFR part
93, subpart A, apply only if the EPA
Regional Administrator or the director
of the state air agency has made a
finding that emissions of these
pollutants within the area are a
significant contributor to the PM2.5
241 40
CFR 93.118(e)(4)(v).
CFR 51.1012(a), 51.1013(a)(1).
243 40 CFR 51.1013(a)(4) and 81 FR 58010, 58058
and 58063–58064. Because the area has failed to
attain the 1997 24-hour PM2.5 NAAQS by the
Serious area attainment date, and it would serve no
purpose for the plan to include budgets for the EPA
to evaluate conformity for the dates associated with
the Serious area attainment date, the applicable
attainment date for the purposes of our evaluation
is the section 189(d) projected attainment date of
December 31, 2020.
244 81 FR 58010, 58063–58064.
242 40
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nonattainment problem and has so
notified the MPO and Department of
Transportation (DOT), or if the
applicable implementation plan (or
implementation plan submission)
includes any of these pollutants in the
approved (or adequate) budget as part of
the RFP, attainment, or maintenance
strategy.245
By contrast, transportation conformity
requirements apply with respect to
emissions of NOX unless both the EPA
Regional Administrator and the director
of the state air agency have made a
finding that transportation-related
emissions of NOX within the
nonattainment area are not a significant
contributor to the PM2.5 nonattainment
problem and have so notified the MPO
and DOT, or the applicable
implementation plan (or
implementation plan submission) does
not establish an approved (or adequate)
budget for such emissions as part of the
RFP, attainment, or maintenance
strategy.246
It is not always necessary for states to
establish motor vehicle emissions
budgets for all PM2.5 precursors. The
PM2.5 SIP Requirements Rule allows a
state to demonstrate that emissions of
certain precursors do not contribute
significantly to PM2.5 levels that exceed
the NAAQS in a nonattainment area, in
which case the state may exclude such
precursor(s) from its control evaluations
for the specific NAAQS at issue. If a
state successfully demonstrates that the
emissions of one or more of the PM2.5
precursors from all sources do not
contribute significantly to PM2.5 levels
in the subject area, then it is not
necessary to establish motor vehicle
emissions budgets for such precursor(s).
Alternatively, the transportation
conformity regulations contain criteria
for determining whether emissions of
one or more PM2.5 precursors are
insignificant for transportation
conformity purposes.247 For a pollutant
or precursor to be considered an
insignificant contributor based on the
transportation conformity rule’s criteria,
the control strategy SIP must
demonstrate that it would be
unreasonable to expect that such an area
would experience enough motor vehicle
emissions growth in that pollutant and/
or precursor for a NAAQS violation to
occur. Insignificance determinations are
based on factors such as air quality, SIP
motor vehicle control measures, trends
245 40 CFR 93.102(b)(3), 93.102(b)(2)(v), and
93.122(f); see also Conformity Rule preambles at 69
FR 40004, 40031–40036 (July 1, 2004), 70 FR 24280,
24283–24285 (May 6, 2005) and 70 FR 31354 (June
1, 2005).
246 40 CFR 93.102(b)(2)(iv).
247 40 CFR 93.109(f).
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and projections of motor vehicle
emissions, and the percentage of the
total attainment plan emissions
inventory for the NAAQS at issue that
is comprised of motor vehicle
emissions. The EPA’s rationale for
providing for insignificance
determinations is described in the July
1, 2004 revision to the Transportation
Conformity Rule.248
Transportation conformity trading
mechanisms are allowed under 40 CFR
93.124 where a state establishes
appropriate mechanisms for such trades.
The basis for the trading mechanism is
the SIP attainment modeling that
establishes the relative contribution of
each PM2.5 precursor pollutant. The
applicability of emissions trading
between conformity budgets for
conformity purposes is described in 40
CFR 93.124(c).
The EPA’s process for determining the
adequacy of a budget consists of three
basic steps: (1) Notifying the public of
a SIP submittal; (2) providing the public
the opportunity to comment on the
budget during a public comment period;
and (3) making a finding of adequacy or
inadequacy. The EPA can notify the
public by either posting an
announcement that the EPA has
received SIP budgets on the EPA’s
adequacy website,249 or through a
Federal Register notice of proposed
rulemaking when the EPA reviews the
adequacy of an implementation plan
budget simultaneously with its review
and action on the SIP itself.250
2. Summary of the State’s Submission
The 2018 PM2.5 Plan includes budgets
for direct PM2.5 and NOX emissions,
calculated using annual average daily
emissions, for 2017, 2020, and 2023
(RFP milestone year, attainment year,
and post-attainment quantitative
milestone year, respectively).251 The
Plan establishes separate direct PM2.5
and NOX subarea budgets for each
county, and partial county (for Kern
County), in the San Joaquin Valley.252
CARB calculated the budgets using
EMFAC2014, CARB’s latest version of
the EMFAC model for estimating
emissions from on-road vehicles
operating in California that was
available at the time of Plan
53177
development, and the latest modeled
vehicle miles traveled and speed
distributions from the San Joaquin
Valley MPOs from the Final 2017
Federal Transportation Improvement
Program, adopted in September 2016.
The budgets reflect annual average
emissions because those emissions are
linked with the District’s attainment
demonstration for the 1997 24-hour
PM2.5 NAAQS.
The direct PM2.5 budgets include
tailpipe, brake wear, and tire wear
emissions but do not include paved
road dust, unpaved road dust, and road
construction dust emissions.253 The
State is not required to include reentrained road dust in the budgets
under section 93.103(b)(3) unless the
EPA or the State has made a finding that
these emissions are significant. Neither
the State nor the EPA has made such a
finding, but the Plan does include a
discussion of the significance/
insignificance factors for re-entrained
road dust.254 The budgets included in
the 2018 PM2.5 Plan for purposes of the
1997 24-hour PM2.5 NAAQS are shown
in Table 8.
TABLE 8—MOTOR VEHICLE EMISSION BUDGETS FOR THE SAN JOAQUIN VALLEY FOR THE 1997 24-HOUR PM2.5 NAAQS
[Annual average, tpd]
2017
(RFP year)
County
PM2.5
Fresno ......................................................
Kern ..........................................................
Kings ........................................................
Madera .....................................................
Merced .....................................................
San Joaquin .............................................
Stanislaus .................................................
Tulare .......................................................
2020
(Attainment year)
NOX
0.9
0.8
0.2
0.2
0.3
0.7
0.4
0.4
PM2.5
28.5
28.0
5.8
5.3
10.7
14.9
11.9
10.8
2023
(Post-attainment year)
NOX
0.9
0.8
0.2
0.2
0.3
0.6
0.4
0.4
PM2.5
25.3
23.3
4.8
4.2
8.9
11.9
9.6
8.5
NOX
0.8
0.7
0.2
0.2
0.3
0.6
0.4
0.4
15.1
13.3
2.8
2.5
5.3
7.6
6.1
5.2
Source: 2018 PM2.5 Plan, Appendix D, Table 3–1. Budgets are rounded to the nearest tenth of a ton.
The State did not include budgets for
VOC, SO2, or ammonia. As discussed in
section IV.B of this preamble, the State
submitted a PM2.5 precursor
demonstration documenting its
conclusion that control of these
precursors would not significantly
contribute to attainment of the 1997 24hour PM2.5 NAAQS, and the EPA is
proposing to approve the precursor
demonstration. Therefore, if the EPA
approves the demonstration, the State
would not be required to submit budgets
for these precursors. The State included
a discussion of the significance/
insignificance factors for ammonia, SO2,
FR 40004.
CFR 93.118(f)(1).
250 40 CFR 93.118(f)(2).
251 2018 PM
2.5 Plan, Appendix D, Table 3–1.
and VOC to demonstrate a finding of
insignificance under the transportation
conformity rule.255
In the submittal letter for the 2018
PM2.5 Plan, CARB requested that the
EPA limit the duration of the approval
of the budgets to the period before the
effective date of the EPA’s adequacy
finding for any subsequently submitted
budgets.256
Conformity Trading Mechanism
The 2018 PM2.5 Plan also includes a
proposed trading mechanism for
transportation conformity analyses that
would allow future decreases in NOX
248 69
252 40
249 40
253 2018
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CFR 93.124(c) and (d).
PM2.5 Plan, Appendix D, D–122 and D–
123.
254 Id.
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emissions from on-road mobile sources
to offset any on-road increases in direct
PM2.5 emissions. The State is proposing
to use a 2 to 1 NOX to PM2.5 ratio for
the 1997 24-hour PM2.5 NAAQS. This
ratio was derived by performing a
sensitivity analysis based on a 30
percent reduction of NOX or PM2.5
emissions and calculating the
corresponding effect on design values at
sites in Bakersfield and Fresno.
To ensure that the trading mechanism
does not affect the ability of the San
Joaquin Valley to meet the NOX budget,
the NOX emissions reductions available
to supplement the PM2.5 budget would
255 40
CFR 93.109(f).
dated May 9, 2019, from Richard W.
Corey, Executive Officer, CARB, to Mike Stoker,
Regional Administrator, EPA Region 9, 3.
256 Letter
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only be those remaining after the NOX
budget has been met.257 The Plan also
provides that the San Joaquin Valley
MPOs shall clearly document the
calculations used in the trading, along
with any additional reductions of NOX
and PM2.5 emissions in the conformity
analysis.
3. The EPA’s Review of the State’s
Submission
The EPA generally first conducts a
preliminary review of budgets
submitted with an attainment or
maintenance plan for PM2.5 for
adequacy, prior to taking action on the
plan itself, and did so with respect to
the PM2.5 budgets in the 2018 PM2.5
Plan. On June 18, 2019, the EPA
announced the availability of the 2018
PM2.5 Plan with MVEBs and a 30-day
public comment period. This
announcement was posted on the EPA’s
Adequacy website at: https://
www.epa.gov/state-and-localtransportation/state-implementationplans-sip-submissions-currently-underepa. The comment period for this
notification ended on July 18, 2019. We
did not receive any comments during
this comment period.
Based on our proposal to approve the
State’s demonstration that emissions of
ammonia, SO2, and VOCs do not
contribute significantly to PM2.5 levels
that exceed the 1997 24-hour PM2.5
NAAQS in the San Joaquin Valley, as
discussed in section IV.B of this
proposal, and the information about
ammonia, SO2, and VOC emissions in
the Plan, the EPA proposes to find that
it is not necessary to establish motor
vehicle emissions budgets for
transportation-related emissions of
ammonia, SO2, and VOC to attain the
1997 24-hour PM2.5 NAAQS in the San
Joaquin Valley. Based on the
information about re-entrained road
dust in the Plan and in accordance with
40 CFR 93.102(b)(3), the EPA proposes
to find that it is not necessary to include
re-entrained road dust emissions in the
budgets for 1997 24-hour PM2.5 NAAQS
in the San Joaquin Valley.
For the reasons discussed in sections
IV.D and IV.E of this proposed rule, the
EPA is proposing to approve the
attainment and RFP demonstrations,
respectively, in the SJV PM2.5 Plan. The
2017 RFP and 2020 attainment year
budgets, as shown in Table 8 of this
preamble, are consistent with these
demonstrations, are clearly identified
and precisely quantified, and meet all
other applicable statutory and
regulatory requirements including the
257 2018
PM2.5 Plan, Appendix D, D–126 and D–
127.
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adequacy criteria in 40 CFR
93.118(e)(4). For these reasons, the EPA
proposes to approve the 2017 and 2020
budgets listed in Table 8.258 We provide
a more detailed discussion in section IV
of the EPA’s 1997 24-hour PM2.5 TSD.
The budgets that the EPA is proposing
to approve relate only to the 1997 24hour PM2.5 NAAQS, and our proposed
approval does not affect the status of the
budgets for the 1997 annual PM2.5
NAAQS or the previously-approved
MVEBs for the 2006 PM2.5 NAAQS and
related trading mechanism, which
remain in effect for that PM2.5 NAAQS.
Although the post-attainment year
quantitative milestone is a required
element of the Serious area plan, it is
not necessary to demonstrate
transportation conformity for 2023 or to
use the 2023 budgets in transportation
conformity determinations until such
time as the area fails to attain the 1997
24-hour PM2.5 NAAQS. As discussed in
section V of this document, the EPA is
proposing to find that the San Joaquin
Valley area has attained the 1997 24hour PM2.5 NAAQS. The EPA does not
believe that it is necessary to
demonstrate conformity using postattainment year budgets in areas that
attain by the attainment date. Therefore,
if the EPA finalizes the determination
that the San Joaquin Valley area attained
by the December 31, 2020 attainment
date, the requirement for postattainment year budgets will no longer
apply in the area for the 1997 24-hour
PM2.5 NAAQS.
As noted above, the State included a
trading mechanism to be used in
transportation conformity analyses that
would be used in conjunction with the
budgets in the 2018 PM2.5 Plan, as
allowed for under 40 CFR 93.124(b).
This trading mechanism would allow
future decreases in NOX emissions from
on-road mobile sources to offset any onroad increases in PM2.5, using a 2 to 1
NOX to PM2.5 ratio for the 1997 24-hour
PM2.5 NAAQS. To ensure that the
trading mechanism does not affect the
ability to meet the NOX budget, the Plan
provides that the NOX emissions
reductions available to supplement the
PM2.5 budget would only be those
remaining after the NOX budget has
been met. The San Joaquin Valley MPOs
will have to document clearly the
calculations used in the trading when
demonstrating conformity, along with
any additional reductions of NOX and
PM2.5 emissions in the conformity
analysis. The trading calculations must
258 Although we are proposing to approve the
2017 budgets, we note that these budgets would not
be used in any future transportation conformity
determinations because the Plan contains budgets
for 2020.
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Fmt 4701
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be performed prior to the final rounding
to demonstrate conformity with the
budgets.
The EPA has reviewed the trading
mechanism as described on pages D–
125 to D–127 in Appendix D of the 2018
PM2.5 Plan and finds it is appropriate for
transportation conformity purposes in
the San Joaquin Valley for the 1997 24hour PM2.5 NAAQS. The methodology
for estimating the trading ratio for
conformity purposes is essentially an
update (based on newer modeling) of
the approach that the EPA previously
approved for the 2008 PM2.5 Plan for the
1997 PM2.5 NAAQS 259 and the 2012
PM2.5 Plan for the 2006 24-hour PM2.5
NAAQS.260 The State’s approach in the
previous plans was to model the
ambient PM2.5 effect of areawide NOX
emissions reductions and of areawide
direct PM2.5 emissions reductions, and
to express the ratio of these modeled
sensitivities as an inter-pollutant trading
ratio.
In the updated analysis for the 2018
PM2.5 plan, the State completed separate
sensitivity analyses for the annual and
24-hour NAAQS and modeled only
transportation related sources in the
nonattainment area. The ratio the State
is proposing to use for transportation
conformity purposes is derived from air
quality modeling that evaluated the
effect of reductions in transportationrelated NOX and PM2.5 emissions in the
San Joaquin Valley on ambient
concentrations at the BakersfieldCalifornia Avenue, Bakersfield-Planz,
Fresno-Garland, and Fresno-Hamilton &
Winery monitoring sites. The modeling
that the State performed to evaluate the
effectiveness of NOX and PM2.5
reductions on ambient 24-hour
concentrations showed NOX to PM2.5
ratios that range from a high of 2.3 at the
Bakersfield-California Avenue monitor
to a low of 1.6 at the Fresno-Hamilton
& Winery monitor.261 In our July 22,
2020 action on the 2018 PM2.5 Plan for
the 2006 PM2.5 NAAQS, we found that
the State’s approach is a reasonable
method to use to develop ratios for
transportation conformity purposes and
approved the 2 to 1 NOX to PM2.5
trading mechanism as an enforceable
component of the transportation
conformity program for the San Joaquin
Valley for the 2006 PM2.5 NAAQS.262
Here, we similarly find that the State’s
approach is reasonable and propose to
259 80 FR 1816, 1841 (January 13, 2015) (noting
the EPA’s prior approval of MVEBs for the 1997
annual and 24-hour PM2.5 standards in the 2008
PM2.5 Plan at 76 FR 69896).
260 81 FR 59876 (August 31, 2016).
261 2018 PM
2.5 Plan, Appendix D, D–126.
262 85 FR 44192.
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approve the 2 to 1 NOX to PM2.5 trading
ratio.
If approved, this trading ratio will
replace the 9 to 1 NOX to PM2.5 trading
ratio approved for the San Joaquin
Valley for analysis years after 2014 for
the 1997 24-hour PM2.5 NAAQS.263
Under the transportation conformity
rule, once budgets are approved, they
cannot be superseded by revised
budgets submitted for the same CAA
purpose and the same year(s) addressed
by the previously approved SIP until the
EPA approves the revised budgets as a
SIP revision. In other words, as a
general matter, such approved budgets
cannot be superseded by revised
budgets found adequate, but rather only
through approval of the revised budgets,
unless the EPA specifies otherwise in its
approval of a SIP by limiting the
duration of the approval to last only
until subsequently submitted budgets
are found adequate.264
In the submittal letter for the 2018
PM2.5 Plan, CARB requested that we
limit the duration of our approval of the
budgets to the period before the
effective date of the EPA’s adequacy
finding for any subsequently submitted
budgets.265 The transportation
conformity rule allows us to limit the
approval of budgets.266 However, we
will consider a state’s request to limit an
approval of its budgets only if the
request includes the following
elements: 267
(1) An acknowledgement and
explanation as to why the budgets under
consideration have become outdated or
deficient;
(2) A commitment to update the
budgets as part of a comprehensive SIP
update; and
(3) A request that the EPA limit the
duration of its approval to the period
before new budgets have been found to
be adequate for transportation
conformity purposes.
CARB’s request includes an
explanation for why the budgets have
become, or will become, outdated or
deficient. In short, CARB has requested
that we limit the duration of the
approval of the budgets in light of the
EPA’s approval of EMFAC2017, an
updated version of the model
(EMFAC2014) used for the budgets in
the SJV PM2.5 Plan.268 EMFAC2017
263 76
FR 69896.
CFR 93.118(e)(1).
265 Letter dated May 9, 2019, from Richard W.
Corey, Executive Officer, CARB, to Mike Stoker,
Regional Administrator, EPA Region 9, 3.
266 40 CFR 93.118(e)(1).
267 67 FR 69139 (November 15, 2002), limiting
our prior approval of MVEBs in certain California
SIPs.
268 On August 15, 2019, the EPA approved and
announced the availability of EMFAC2017, the
264 40
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updates vehicle mix and emissions data
of the previously approved version of
the model, EMFAC2014.
In light of the EPA’s approval of
EMFAC2017, CARB explains that the
budgets in the SJV PM2.5 Plan, which we
are proposing to approve in today’s
action, will become outdated and will
need to be revised using EMFAC2017.
In addition, CARB states that, without
the ability to replace the budgets using
the budget adequacy process, the
benefits of using the updated data may
not be realized for a year or more after
the updated SIP (with the EMFAC2017derived budgets) is submitted, due to
the length of the SIP approval process.
We find that CARB’s explanation for
limiting the duration of the approval of
the budgets is appropriate and provides
us with a reasonable basis for limiting
the duration of the approval of the
budgets.
We note that CARB has not
committed to update the budgets as part
of a comprehensive SIP update, but as
a practical matter, CARB must submit a
SIP revision that includes updated
demonstrations as well as the updated
budgets to meet the adequacy criteria in
40 CFR 93.118(e)(4).269 Therefore, we do
not need a specific commitment for
such a plan at this time. For the reasons
provided above, and in light of CARB’s
explanation for why the budgets will
become outdated and should be
replaced upon an adequacy finding for
updated budgets, we propose to limit
the duration of our approval of the
budgets addressed in this action to the
period before we find revised budgets
based on EMFAC2017 to be adequate.
H. Nonattainment New Source Review
Requirements Under CAA Section
189(e)
CAA section 189(e) specifically
requires that the control requirements
applicable to major stationary sources of
direct PM2.5 also apply to major
stationary sources of PM2.5 precursors,
except where the Administrator
determines that such sources do not
contribute significantly to PM2.5 levels
that exceed the NAAQS in the area.270
The control requirements applicable to
major stationary sources of direct PM2.5
in a Serious PM2.5 nonattainment area
include, at minimum, the requirements
latest update to the EMFAC model for use by the
State and local governments to meet CAA
requirements. 84 FR 41717.
269 Under 40 CFR 93.118(e)(4), the EPA will not
find a budget in a submitted SIP to be adequate
unless, among other criteria, the budgets, when
considered together with all other emissions
sources, are consistent with applicable
requirements for RFP and attainment. 40 CFR
93.118(e)(4)(iv).
270 General Preamble, 13539 and 13541–13542.
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of a nonattainment NSR permit program
meeting the requirements of CAA
sections 172(c)(5) and 189(b)(3). As part
of our April 7, 2015 final action to
reclassify the San Joaquin Valley area as
Serious nonattainment for the 1997
PM2.5 standards, we established a May
7, 2016 deadline for the State to submit
nonattainment NSR SIP revisions
addressing the requirements of CAA
sections 189(b)(3) and 189(e) of the Act
for the 1997 PM2.5 NAAQS.271
California submitted nonattainment
NSR SIP revisions to address the
subpart 4 requirements for the San
Joaquin Valley Serious PM2.5
nonattainment area on November 20,
2019.272 We are not proposing any
action on this submission at this time.
We will act on this submission through
a separate rulemaking, as appropriate.
V. Determination of Attainment by the
Attainment Date
A. Requirements for Attainment
Determinations
Sections 179(c)(1) and 188(b)(2) of the
CAA require the EPA to determine
whether a state with a PM2.5
nonattainment area attained the
applicable PM2.5 NAAQS by the
applicable attainment date, based on the
area’s air quality as of the attainment
date. A determination of whether an
area’s air quality currently meets the
PM2.5 NAAQS is generally based upon
the most recent three years of complete,
quality-assured data gathered at
established State and Local Air
Monitoring Stations (SLAMS) in a
nonattainment area and entered into the
EPA’s Air Quality System (AQS)
database. Data from ambient air
monitors operated by state/local
agencies in compliance with the EPA
monitoring requirements must be
submitted to AQS. Monitoring agencies
annually certify that these data are
accurate to the best of their knowledge.
Accordingly, the EPA relies primarily
on data in AQS when determining the
attainment status of areas.273 The EPA
reviews all data to determine the area’s
air quality status in accordance with 40
CFR part 50, Appendix N.
Under EPA regulations in 40 CFR 50.7
and in accordance with Appendix N,
the 1997 24-hour PM2.5 NAAQS are met
when the design value is less than or
equal to 65 mg/m3 (based on the
rounding convention in 40 CFR part 50,
271 80
FR 18528, 18533.
dated November 15, 2019, from Richard
W. Corey, Executive Officer, CARB, to Michael
Stoker, Regional Administrator, EPA Region IX.
273 See 40 CFR 50.7; 40 CFR part 50, Appendix
L; 40 CFR part 53; 40 CFR part 58, and 40 CFR part
58, appendices A, C, D, and E.
272 Letter
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Appendix N) at each eligible monitoring
site within the area. Data completeness
requirements for a given year are met
when at least 75 percent of the
scheduled sampling days for each
quarter have valid data.274
B. Monitoring Network Considerations
Section 110(a)(2)(B)(i) of the CAA
requires states to establish and operate
air monitoring networks to compile data
on ambient air quality for all criteria
pollutants. The monitoring
requirements are specified in 40 CFR
part 58. These requirements are
applicable to state, and where delegated,
local air monitoring agencies that
operate criteria pollutant monitors. The
regulations in 40 CFR part 58 establish
specific requirements for operating air
quality surveillance networks to
measure ambient concentrations of
PM2.5, including requirements for
measurement methods, network design,
quality assurance procedures, and in the
case of large urban areas, the minimum
number of monitoring sites designated
as SLAMS.
In section 4.7 of Appendix D to 40
CFR part 58, the EPA specifies
minimum monitoring requirements for
PM2.5 to operate at SLAMS. SLAMS
produce data comparable to the
NAAQS, and therefore, the monitor
must be an approved federal reference
method (FRM), federal equivalent
method (FEM), or approved regional
method (ARM). The minimum number
of SLAMS required is described in
section 4.7.1 and can be met by either
filter-based or continuous FRMs or
FEMs. The monitoring regulations also
provide that each core-based statistical
area (CBSA) must operate a minimum
number of PM2.5 continuous
monitors; 275 however, this requirement
can be met by either an FEM or a nonFEM continuous monitor, and the
continuous monitors can be located
with other SLAMS or at a different
location. Consequently, the monitoring
requirements for PM2.5 can be met with
filter-based FRMs/FEMs, continuous
FEMs, continuous non-FEMs, or a
combination of monitors at each
required SLAMS.
Under 40 CFR 58.10, states are
required to submit annual monitoring
network plans to the EPA.276 Within the
San Joaquin Valley, CARB and the
District are the agencies responsible for
assuring that the area meets air quality
monitoring requirements. CARB and
SJVUAPCD submit monitoring network
plans to the EPA annually. These plans
274 40
CFR part 50, Appendix N, section 4.2(b).
CFR part 58, Appendix D, section 4.7.2.
276 40 CFR 58.10(a)(1).
275 40
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describe and discuss the status of the air
monitoring network, as required under
40 CFR 58.10. The EPA reviews these
annual network plans for compliance
with the applicable reporting
requirements in 40 CFR part 58. With
respect to PM2.5, we have found that the
CARB and SJVUAPCD annual network
plans meet the applicable requirements
under 40 CFR part 58.277
During the 2018–2020 period, PM2.5
ambient concentration data that are
eligible for use in determining whether
an area has attained the PM2.5 NAAQS
were collected at a total of 18 sites
within the San Joaquin Valley: 5 sites in
Fresno County; 3 sites in Kern County;
2 sites each in Kings, Merced, San
Joaquin, and Stanislaus counties; and 1
site each in Madera and Tulare counties.
The District operates 12 of these sites
while CARB operates 6 of these sites.
All of the sites are designated SLAMS
for PM2.5.278 The primary monitors are
FRMs at 5 of the 18 sites and beta
attenuation monitor FEMs at 13 of the
18 sites. Overall, the District’s PM2.5
monitoring network meets, and in
several Metropolitan Statistical Areas
(MSAs) exceeds, the PM2.5 minimum
monitoring requirements for the San
Joaquin Valley.
Based on our review of the PM2.5
monitoring network as summarized
above, we find that the monitoring
network in the San Joaquin Valley is
adequate for the purpose of collecting
ambient PM2.5 concentration data for
use in determining whether the San
Joaquin Valley attained the 1997 24hour PM2.5 NAAQS by the December 31,
2020 attainment date.
277 Letter dated November 5, 2018, from Gwen
Yoshimura, Manager, Air Quality Analysis Office,
EPA Region IX, to Sheraz Gill, Deputy Air Pollution
Control Office, SJVUAPCD; letter dated November
6, 2019, from Gwen Yoshimura, Manager, Air
Quality Analysis Office, EPA Region IX, to Jon
Klassen, Director of Strategies and Incentives,
SJVUAPCD; letter dated October 26, 2020, from
Gwen Yoshimura, Manager, Air Quality Analysis
Office, EPA Region IX, to Jon Klassen, Director of
Strategies and Incentives, SJVUAPCD; letter dated
November 26, 2018, from Gwen Yoshimura,
Manager, Air Quality Analysis Office, EPA Region
IX, to Ravi Ramalingam, Chief, Consumer Products
and Air Quality Assessment Branch, CARB; letter
dated November 26, 2019, from Gwen Yoshimura,
Manager, Air Quality Analysis Office, EPA Region
IX, to Ravi Ramalingam, Chief, Consumer Products
and Air Quality Assessment Branch, CARB; and
letter dated November 5, 2020, from Gwen
Yoshimura, Manager, Air Quality Analysis Office,
EPA Region IX, to Ravi Ramalingam, Chief,
Consumer Products and Air Quality Assessment
Branch, CARB.
278 There are a number of other PM
2.5 monitoring
sites within the valley, including other sites
operated by the District, the National Park Service,
and certain Indian tribes, but the data collected
from these sites are non-regulatory and not eligible
for use in determining whether the San Joaquin
Valley has attained the PM2.5 NAAQS.
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C. Data Considerations and Proposed
Determination
Under 40 CFR 58.15, monitoring
agencies must certify, on an annual
basis, that data collected at all SLAMS
and at all FRM, FEM, and ARM SPM
stations meet the EPA’s quality
assurance requirements. In doing so,
monitoring agencies must certify that
the previous year of ambient
concentration and quality assurance
data are submitted to AQS and that the
ambient concentration data are accurate.
CARB annually certifies that the data
the agency submits to AQS are quality
assured, including the data collected at
monitoring sites in the San Joaquin
Valley.279 SJVUAPCD does the same for
data submitted to AQS from monitoring
sites operated by the District.280
As noted above, CAA sections
179(c)(1) and 188(b)(2) require the EPA
to determine whether a PM2.5
nonattainment area attained the
applicable PM2.5 NAAQS by the
applicable attainment date, based on the
area’s air quality as of the attainment
date. The SJV PM2.5 Plan includes a
modeled demonstration of attainment
by December 31, 2020, for the 1997 24hour PM2.5 NAAQS. Thus, the EPA’s
evaluation of whether the San Joaquin
Valley PM2.5 nonattainment area has
attained the 1997 24-hour PM2.5 NAAQS
is based on our review of the monitoring
data recorded during the three years
preceding the attainment date (2018–
2020). Our review also takes into
account the adequacy of the PM2.5
monitoring network in the
nonattainment area and the reliability of
the data collected by the network as
discussed in the previous sections of
this document.
With respect to data completeness, we
determined that the data collected by
CARB and the District meet the
quarterly completeness criterion for all
12 quarters of the three-year period at
most of the PM2.5 monitoring sites in the
San Joaquin Valley. More specifically,
among the 18 PM2.5 monitoring sites
from which regulatory data are
available, the data from 5 of the sites did
not meet the 75 percent completeness
criterion (for each quarter); however, the
data from all but 3 sites (Fresno–
279 For example, see letter dated June 21, 2021,
from Sylvia Vanderspek, Chief, Air Quality
Planning Branch, CARB, to Gwen Yoshimura,
Manager, Air Quality Analysis Office, EPA Region
9, with enclosures, certifying calendar year 2020
ambient air quality data and quality assurance data.
280 For example, see letter dated June 22, 2021,
from Jessica Olsen, Program Manager, SJVUAPCD,
to Elizabeth Adams, Director, Air and Radiation
Division, EPA Region IX, with attachments,
certifying calendar year 2020 ambient air quality
data and quality assurance data.
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Foundry (AQS ID: 06–019–2016),
Manteca (AQS ID: 06–077–2010), and
Clovis–Villa (AQS ID: 06–019–5001))
are sufficient nonetheless to produce a
valid design value for the 1997 24-hour
PM2.5 NAAQS pursuant to the rules
governing design value validity in 40
CFR part 50, Appendix N, section 4.2.
We note that monitors with incomplete
data in one or more quarters may still
produce valid design values if the
conditions for applying the EPA’s data
substitution test are met.281 The
Bakersfield–Airport (Planz) (AQS ID:
06–029–0016) and Hanford–Irwin (AQS
ID: 06–031–1004) monitoring sites had
incomplete data in the 4th quarter and
3rd quarter of 2018, respectively;
however, both sites had between 50 and
75 percent data completeness for these
quarters and have valid design values
after applying the maximum quarterly
value data substitution test.
The Manteca monitoring site recorded
data amounting to less than 75 percent
completeness during the 1st, 2nd, and
3rd quarters of 2019 (61 percent, 66
percent, and 67 percent, respectively)
due to ongoing instrument operational
issues. Under Appendix N, section
4.2(b) data shall be considered valid, in
spite of quarters with incomplete data,
if the resulting annual 98th percentile
value or resulting 24-hour NAAQS
design value exceeds the standard. Here,
the incomplete annual 98th percentile
value, 26.8 mg/m3, is well below the
standard, and the resulting design value
for the site, 59 mg/m3, is also below the
standard. Therefore, this provision of
section 4.2(b) does not validate the 2019
Manteca monitoring site data. Like
Bakersfield–Airport (Planz) and
Hanford–Irwin, the data for the Manteca
site qualify for the maximum quarterly
value data substitution test under 40
CFR part 50, Appendix N, section 4.2(c).
However, upon applying the data
substitution test to the Manteca
monitoring site data, we find that the
data do not pass the test (i.e., after
substituting the highest reported daily
maximum PM2.5 value for a quarter for
all missing daily data in the matching
deficient quarter, the resulting test
design value was above the 1997 24hour PM2.5 NAAQS). Because the data
substitution test results in a test design
value above the NAAQS, the Manteca
monitoring site 2019 design value is
considered invalid. The EPA then
reviewed additional information about
the monitoring network and air quality
data, including historical 24-hour PM2.5
design value trends, to assess if the data
collection deficiency, in the context of
281 See 40 CFR part 50, Appendix N, section
4.2(b).
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data that otherwise show attainment,
precludes the EPA from determining
that the San Joaquin Valley area attained
the 1997 24-hour PM2.5 NAAQS during
the 2018–2020 period.
First, although the 2019 data were
incomplete, the available data that were
collected over a substantial amount of
the year show zero exceedances of the
NAAQS.
Second, the Manteca monitoring site
has not historically been the 24-hour
PM2.5 design value site for the San
Joaquin Valley area. For example, the
Bakersfield–California (AQS ID: 06–
029–0014) monitoring site was the
design value site for the 24-hour PM2.5
NAAQS for 2011 to 2013, the
Bakersfield–Airport (Planz) monitoring
site was the design value site in 2014,
the Corcoran–Patterson (AQS ID: 06–
031–0004) monitoring site was the
design value site from 2015 to 2019, and
the Modesto–14th Street (AQS ID: 06–
099–0005) monitoring site was the
design value site in 2020.
Third, an assessment of long-term
trends at the Manteca monitoring site
and nearby monitoring sites shows
nearby sites have design values below
the 24-hour PM2.5 NAAQS and the
Manteca site typically has lower design
values compared to nearby sites. For
example, during the 2013 to 2020
period, the Manteca monitoring site had
consistently lower design values for the
24-hour PM2.5 NAAQS than the
Stockton–Hazelton (AQS ID: 06–077–
1002) and Modesto–14th Street
monitoring sites, which are located
approximately 11 miles and 18 miles,
respectively, from the Manteca
monitoring site. The Stockton–Hazelton
and Modesto–14th Street monitoring
sites have complete annual 24-hour
design values that are below the 1997
24-hour PM2.5 NAAQS (after excluding
monitored exceedances associated with
the August 20–24, 2020 wildfire
exceptional event, as discussed below)
and provide an appropriate comparison
and characterization of air quality for
the areas surrounding the Manteca
monitoring site. Thus, because the data
that were collected provide a 98th
percentile value below the standard,
and the Manteca monitoring site has
historically lower design value
concentrations relative to the 24-hour
PM2.5 NAAQS and design values at
nearby locations, we find that the
incomplete data should not preclude the
EPA from determining that the San
Joaquin Valley area has attained the
1997 24-hour PM2.5 NAAQS.
The remaining two sites, Fresno–
Foundry and Clovis–Villa, recorded
data amounting to less than 50 percent
completeness during multiple quarters
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53181
during the 2018–2020 period.
Specifically, the Fresno–Foundry
monitoring site recorded less than 50
percent data capture during all four
quarters of 2018 and 2019 and the
Clovis–Villa monitoring site recorded
less than 50 percent data capture during
the 2nd and 4th quarters of 2019. Thus,
the data in these quarters are not eligible
for the maximum quarterly value data
substitution test under the provisions in
40 CFR part 50 Appendix N, section
4.2(c)(i), which state that if any quarter
has less than 50 percent data capture,
then the required test conditions are not
met and the substitution test cannot be
used. Additionally, the data collected at
these sites did not result in an 98th
percentile value or resulting 24-hour
NAAQS design value that exceeds the
standard under the provision of
Appendix N section 4.2(b). Therefore,
the design values at these two sites are
considered invalid. However, the EPA
reviewed historical 24-hour PM2.5
design value trends and the causes of
the incomplete data in the context of
data that otherwise show attainment,
and found that the data collection
deficiency should not preclude a
determination that the San Joaquin
Valley area attained the 1997 24-hour
PM2.5 NAAQS during the 2018–2020
period.
The Fresno–Foundry monitoring site
began operation on January 1, 2020.
Although data completeness was 98
percent for year 2020, the data
completeness requirements for the
2018–2020 period are not met since the
site was not yet operational and thus
data were not collected in 2018 and
2019. Because the incomplete data at
the Fresno–Foundry monitoring site is
due to the site having only begun
operation in 2020, the incomplete data
should not preclude the EPA from
determining whether the area has
attained the NAAQS. Upon excluding
monitored exceedances associated with
the August 20–24, 2020 wildfire
exceptional event, as discussed below,
the Fresno–Foundry monitoring site has
an incomplete 2020 design value of 64
mg/m3, which is below the level of the
1997 24-hour PM2.5 NAAQS.
The Clovis–Villa monitoring site
recorded less than 75 percent data
capture during the 2nd, 3rd, and 4th
quarters of 2019 (48 percent, 66 percent,
and 41 percent, respectively) due to
ongoing instrument operational issues.
Because the data substitution test under
40 CFR part 50, Appendix N, section
4.2(c) requires each quarter to have data
completeness of at least 50 percent, the
Clovis-Villa 2019 data do not qualify for
the data substitution test. Like Manteca,
the Clovis–Villa site has not historically
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been the 24-hour PM2.5 design value
site. An assessment of long-term trends
at the Clovis–Villa monitoring site and
a nearby monitoring site shows that the
Clovis–Villa site has historically had
design values below the 24-hour PM2.5
NAAQS and has had lower design
values compared to the nearby site.
During the 2011 to 2019 period, the
Clovis–Villa monitoring site
consistently had lower design values for
the 24-hour PM2.5 NAAQS than the
Fresno–Garland monitoring site, which
is located approximately four miles
from Clovis–Villa.282 The Fresno–
Garland site has a complete 2020 annual
24-hour design value below the 1997 24hour PM2.5 NAAQS and provides an
appropriate comparison and
characterization of air quality for the
area surrounding the Clovis–Villa
monitoring site. Furthermore, the
District exceeds the PM2.5 minimum
monitoring requirements for three PM2.5
SLAMs monitors in the Fresno MSA as
they are currently operating five SLAMs
monitors.
Thus, based on the historical design
value concentrations at the Clovis–Villa
monitoring site relative to the 24-hour
PM2.5 NAAQS and the nearest site, we
find that the incomplete data at the
Clovis–Villa monitoring site should not
preclude the EPA from determining the
San Joaquin Valley area has attained the
1997 24-hour PM2.5 NAAQS.
Table 5 shows the 24-hour PM2.5
design values at each of the 18 SLAMS
monitoring sites within the San Joaquin
Valley nonattainment area for the most
recent three-year period (2018–2020).
The data indicate that the San Joaquin
Valley area likely experienced higher
than normal PM2.5 concentrations in
2018 and 2020 due to wildfire impacts
during the summer and fall months.283
Table 5 shows that 98th percentile
concentrations at all 18 monitors in the
San Joaquin Valley area with data
spanning 2018 to 2020 are significantly
higher in 2018 and 2020 relative to
concentrations in 2019, again, likely due
to the wildfires in those years.
Accordingly, the 2018–2020 design
values in Table 5 may also be higher
than normal at certain monitoring sites
due to potential wildfire impacts within
the 2018–2020 data period.
Nevertheless, the data show that the 24hour design value for the 2018–2020
period was equal to or less than 65
mg/m3 (i.e., the level of the 1997 24-hour
PM2.5 NAAQS) at all monitors after
excluding monitored exceedances
specifically associated with the August
20–24, 2020 wildfire exceptional event,
as discussed below. Therefore, we are
proposing to determine, based on
complete (or otherwise not inconsistent,
as described above), quality-assured,
and certified data for 2018–2020, that
the San Joaquin Valley area has attained
the 1997 24-hour PM2.5 NAAQS,
consistent with attainment of the
standard projected by the State in the
SJV PM2.5 Plan.
TABLE 5—2018–2020 24-HOUR PM2.5 DESIGN VALUES FOR THE SAN JOAQUIN VALLEY NONATTAINMENT AREA
98th percentile (μg/m3)
County
General location site
Fresno ...............
Kern ..................
Kings .................
Madera ..............
Merced ..............
San Joaquin ......
Stanislaus .........
Tulare ................
2020
2018–2020
24-hour design
values
(μg/m3)
................
................
................
................
................
................
................
................
................
................
................
................
................
................
................
................
................
................
61.
62.
64 (Inv).a
62 (Inv).b
54.
55.
64.
61.
64.
64.
54.
53.
53.
64.
59 (Inv).d
65.
64.
64.
AQS ID
Fresno—Pacific ....................................
Fresno—Garland .................................
Fresno—Foundry .................................
Clovis—Villa .........................................
Tranquillity ............................................
Bakersfield—Airport (Planz) ................
Bakersfield—California Ave .................
Bakersfield—Golden State Highway ...
Corcoran—Patterson ...........................
Hanford—Irwin .....................................
Madera—Avenue 14 ............................
Merced—M Street ................................
Merced—Coffee ...................................
Stockton—Hazelton .............................
Manteca ...............................................
Modesto—14th Street ..........................
Turlock .................................................
Visalia ..................................................
06–019–5025
06–019–0011
06–019–2016
06–019–5001
06–019–2009
06–029–0016
06–029–0014
06–029–0010
06–031–0004
06–031–1004
06–039–2010
06–047–2510
06–047–0003
06–077–1002
06–077–2010
06–099–0005
06–099–0006
06–107–2002
2018
2019
65.5 ................
63.5 ................
Inc ..................
57.0 ................
51.4 ................
60.8 ................
69.2 ................
60.9 ................
78.0 ................
78.2 ................
50.2 ................
52.7 ................
56.0 ................
92.3 ................
84.6 c ..............
100.4 ..............
88.6 ................
63.4 ................
37.1 ................
36.9 ................
Inc ..................
28.0 (Inc) ........
17.1 ................
46.7 ................
43.4 ................
44.3 ................
45.1 ................
41.1 ................
23.9 ................
29.5 ................
23.4 ................
32.9 ................
26.8 (Inc) ........
28.4 ................
36.0 ................
45.5 ................
81.0
85.0
63.9
99.5
92.5
57.1
79.2
76.9
69.0
72.6
87.7
77.1
78.3
65.9
66.9
67.1
67.7
83.4
Source: EPA, 2020 AQS Design Value Report, AMP480, accessed September 1, 2021.The Design Value Report excludes measurements with
regionally concurred exceptional event flags. AQS reports for 24-hour PM2.5 data are only available for the 2006 24-hour PM2.5 NAAQS as a Pollutant Standard, thus this report only reflects the 2006 24-hour PM2.5 NAAQS and does not include the 1997 24-hour PM2.5 NAAQS as a Pollutant Standard. Subsequently, AQS only allows the EPA to place concurrence flags on data associated with the 2006 24-hour PM2.5 NAAQS. 40
CFR part 50 Appendix N specifies the data handling and design value calculations for both the 2006 24-hour PM2.5 NAAQS and the 1997 24hour PM2.5 NAAQS. The design values in the Design Value Report for the 2006 24-hr PM2.5 NAAQS for the San Joaquin Valley nonattainment
area are the same as would be expected for the 1997 24-hr PM2.5 NAAQS if the exceptional events for that NAAQS were correctly represented
in AQS.
Notes: Inc = Incomplete data. Inv = Invalid design value due to incomplete data.
a The 2018–2020 design value at Fresno–Foundry (AQS ID: 06–019–2016) is based on concentration data from January 1, 2020 to December
31, 2020. The site began operation in 2020; therefore, data from January 1, 2018 to December 31, 2019 are not available. Based on 40 CFR
part 50, Appendix N, section 4.2(b), three years of valid annual PM2.5 98th percentile mass concentrations are required to produce a valid 24hour PM2.5 NAAQS design value. Thus, the Fresno–Foundry 2018–2020 design value is considered invalid.
b Based on the design value calculation methodologies described in 40 CFR part 50, Appendix N, section 4.2(b), the Clovis–Villa (AQS ID: 06–
019–5001) 2018–2020 design value is considered invalid due to incomplete data in the 2nd, 3rd, and 4th quarters of 2019.
282 The Clovis–Villa and Fresno–Garland
monitoring sites have the same 2020 design value
of 62 mg/m3.
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c Identification of the 98th percentile 24-hour concentration is based on the number of creditable samples in a given year. See 40 CFR part 50,
appendix N, section 4.5. Specifically, in any year for which there are at least 351 creditable samples, the 98th percentile is the 8th highest concentration, and as the number of creditable samples decreases the 98th percentile concentration is represented by a data point closer to the
maximum concentration. The number of creditable samples in 2018 for Manteca is reflected inaccurately in AQS and results in an inaccurate
2018 98th percentile concentration and 2018–2020 design value. Table 5 reflects the 2018 98th percentile concentration and 2018–2020 design
value based on the corrected number of creditable samples. See memorandum dated August 6, 2021, from Dena Vallano, EPA Region IX, to
Docket EPA–R09–OAR–2021–0261, Subject: ‘‘San Joaquin Valley, CA 1997 24-hour PM2.5 Nonattainment Area, Manteca Monitoring.’’
d Based on the design calculation methodologies described in 40 CFR part 50, Appendix N, section 4.2(b), the Manteca (AQS ID: 06–077–
2010) 2018–2020 design value is considered invalid due to incomplete data in the 1st, 2nd, and 3rd quarters of 2019.
In the EPA’s review of monitoring
data for the 1997 24-hour PM2.5 NAAQS
for the San Joaquin Valley
nonattainment area, the EPA is
excluding certain exceedances of the
standard from the attainment
determination presented herein because
they were the result of exceptional
events. Under the EPA’s Exceptional
Events Rule (EER),284 exceedances
flagged as exceptional events will only
be considered for EPA concurrence if
the data affect one of the types of
regulatory actions specified by the EER.
The State has submitted a
demonstration for a wildfire PM2.5
exceptional event covering a total of 30
measured exceedances occurring over 5
consecutive days (August 20–24, 2020)
at 8 monitoring sites within the San
Joaquin Valley nonattainment area that
were critical for informing this
attainment determination.285 The State’s
submission notes that additional San
Joaquin Valley monitoring sites were
affected by wildfire smoke during the
2018–2020 period, but that those dates
were not included in the submission
because they did not cause the 2020
design values to violate the 1997 24hour PM2.5 NAAQS and did not have
regulatory significance relevant to this
determination.286 The EPA reviewed the
documentation that the State provided
to demonstrate that these exceedances
meet the criteria for exceptional events
under the EER. The EPA concurred with
the State’s determinations that, based on
the weight of evidence, the exceedances
were caused by an exceptional event.287
Accordingly, the EPA has determined
that the monitored exceedances
associated with this exceptional event
should not be used for regulatory
purposes, including the evaluation of
whether the San Joaquin Valley
nonattainment area has attained by the
284 40
CFR 50.1(j), (k), (l); 50.14(a)(1)(i); 51.930.
eight monitoring sites covered by the
August 20–24, 2020 wildfire exceptional event
demonstration include Fresno–Foundry,
Bakersfield–Airport (Planz), Corcoran–Patterson,
Hanford–Irwin, Stockton–Hazelton, Manteca,
Modesto–14th Street, and Turlock.
286 SJVUAPCD, ‘‘Exceptional Event
Demonstration for August 2020 PM2.5 Exceedances
due to Wildfires’’, May 11, 2021, 3.
287 Letter dated July 13, 2021, from Elizabeth J.
Adams, Director, Air and Radiation Division, EPA
Region IX, to Michael Benjamin, Division Chief, Air
Quality Planning and Science Division, CARB.
285 The
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attainment date and evaluation of the
CAA Serious area and section 189(d)
plan submission. Excluding these
exceedances caused by uncontrollable
emissions, the EPA proposes to
determine that the San Joaquin Valley
has attained the 1997 24-hour PM2.5
NAAQS, consistent with attainment of
the standard projected by the State in
the SJV PM2.5 Plan.
VI. Summary of Proposed Action and
Request for Public Comment
The EPA is proposing to determine
that the San Joaquin Valley
nonattainment area has attained the
1997 24-hour PM2.5 NAAQS, based on
complete (or otherwise not
inconsistent), quality-assured, and
certified ambient air quality monitoring
data for the 2018–2020 monitoring
period. If finalized, this proposed
determination that the San Joaquin
Valley nonattainment area has attained
the 1997 24-hour PM2.5 NAAQS would
not constitute a redesignation of the area
to attainment. Under CAA section
107(d)(3)(E), redesignations of
nonattainment areas to attainment
require states to meet a number of
additional statutory criteria, including
the EPA’s approval of a SIP revision
demonstrating maintenance of the
standard for 10 years after
redesignation. The designation status of
the San Joaquin Valley area will remain
Serious nonattainment for the 1997 24hour PM2.5 NAAQS until such time as
the EPA determines that the area meets
the CAA requirements for redesignation
to attainment.
For the reasons discussed in this
proposed rule, under CAA section
110(k)(3), the EPA is also proposing to
approve in part and disapprove in part
portions of the SJV PM2.5 Plan submitted
by California that pertain to the 1997 24hour PM2.5 NAAQS in the San Joaquin
Valley nonattainment area as follows:
(1) We are proposing to approve the
following elements as meeting the
Serious nonattainment area planning
requirements:
(a) The 2013 base year emissions
inventories as meeting the requirements
of CAA section 172(c)(3) and 40 CFR
51.1008(b);
(b) the BACM/BACT demonstration as
meeting the requirements of CAA
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section 189(b)(1)(B) and 40 CFR
51.1010(a);
(c) the demonstration (including air
quality modeling) that the Plan provides
for attainment as expeditiously as
practicable as meeting the requirements
of CAA sections 179(d) and 189(b) and
40 CFR 51.1011(b);
(d) the RFP demonstration as meeting
the requirements of CAA sections
172(c)(2) and 171(1) and 40 CFR
51.1012; and
(e) the quantitative milestone
demonstration as meeting the
requirements of CAA section 189(c) and
40 CFR 51.1013;
(2) We are proposing to approve the
following elements as meeting the CAA
section 189(d) planning requirements:
(a) The 2013 base year emissions
inventories as meeting the requirements
of CAA section 172(c)(3) and 40 CFR
51.1008(c);
(b) the BACM/BACT demonstration as
meeting the requirements of CAA
sections 189(a)(1)(C) 288 and 189(b)(1)(B)
and 40 CFR 51.1010(c);
(c) the demonstration that the Plan
will, at a minimum, achieve an annual
five percent reduction in emissions of
NOX as meeting the requirements of
CAA section 189(d) and 40 CFR
51.1010(c);
(d) the demonstration (including air
quality modeling) that the Plan provides
for attainment as expeditiously as
practicable as meeting the requirements
of CAA sections 179(d) and 189(d) and
40 CFR 51.1011(b);
(e) the RFP demonstration as meeting
the requirements of CAA sections
172(c)(2) and 171(1) and 40 CFR
51.1012; and
(f) the quantitative milestone
demonstration as meeting the
requirements of CAA section 189(c) and
40 CFR 51.1013;
(3) We are proposing to approve the
motor vehicle emission budgets for 2017
and 2020 as shown in Table 8 of this
proposed rule because they are derived
288 As discussed in section III.B of this document,
a section 189(d) plan must address any outstanding
Moderate or Serious area requirements that have
not previously been approved. Because we have not
previously approved a subpart 4 RACM
demonstration for the San Joaquin Valley
nonattainment area, we are also proposing to
approve the BACM/BACT demonstration in the SJV
PM2.5 Plan as meeting the subpart 4 RACM/RACT
requirement for the area.
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from approvable RFP and attainment
demonstrations and meet the
requirements of CAA section 176(c) and
40 CFR part 93, subpart A;
(4) We are proposing to approve the
inter-pollutant trading mechanism
provided for use in transportation
conformity analyses for the 1997 24hour PM2.5 NAAQS, in accordance with
40 CFR 93.124(b); and
(5) We are proposing to disapprove
the contingency measure element of the
SJV PM2.5 Plan for the 1997 24-hour
PM2.5 NAAQS for both the Serious area
and CAA section 189(d) planning
requirements for failing to meet the
requirements of CAA section 172(c)(9).
However, based on our proposed
finding of attainment by the applicable
attainment date, we are also proposing
to determine that the contingency
measures requirement will no longer
apply to the San Joaquin Valley area for
the 1997 24-hour PM2.5 NAAQS if we
finalize the determination of attainment
by the applicable attainment date.
Therefore, our proposed disapproval, if
finalized, would not trigger sanctions or
FIP clocks, and we are proposing to
issue a protective finding for
transportation conformity
determinations under 40 CFR
93.120(a)(3) if the proposed disapproval
is finalized.
The EPA is soliciting public
comments on the issues discussed in
this proposed rule. We will accept
comments from the public on this
proposal for the next 30 days.
VII. Statutory and Executive Order
Reviews
any new information collection burdens
but will simply disapprove certain State
requirements for inclusion in the SIP.
C. Regulatory Flexibility Act (RFA)
I certify that this action will not have
a significant economic impact on a
substantial number of small entities
under the RFA. This action will not
impose any requirements on small
entities. This proposed partial SIP
approval and partial disapproval, if
finalized, will not in-and-of itself create
any new requirements but will simply
disapprove certain state requirements
for inclusion in the SIP.
D. Unfunded Mandates Reform Act
(UMRA)
This action does not contain any
unfunded mandate as described in
UMRA, 2 U.S.C. 1531–1538, and does
not significantly or uniquely affect small
governments. This action proposes to
partially approve and partially
disapprove pre-existing requirements
under state or local law and imposes no
new requirements. Accordingly, no
additional costs to state, local, or tribal
governments, or to the private sector,
result from this action.
E. Executive Order 13132: Federalism
This action does not have federalism
implications. It will not have substantial
direct effects on the states, on the
relationship between the national
government and the states, or on the
distribution of power and
responsibilities among the various
levels of government.
B. Paperwork Reduction Act (PRA)
F. Executive Order 13175: Coordination
With Indian Tribal Governments
This action does not have tribal
implications, as specified in Executive
Order 13175, because the SIP revision
that the EPA is proposing to partially
approve and partially disapprove would
not apply on any Indian reservation
land or in any other area where the EPA
or an Indian tribe has demonstrated that
a tribe has jurisdiction, and will not
impose substantial direct costs on tribal
governments or preempt tribal law.
Thus, Executive Order 13175 does not
apply to this action.
This action does not impose an
information collection burden under the
PRA because the proposed partial SIP
approval and partial disapproval, if
finalized, will not in-and-of itself create
G. Executive Order 13045: Protection of
Children From Environmental Health
Risks and Safety Risks
The EPA interprets Executive Order
13045 as applying only to those
Additional information about these
statutes and Executive Orders can be
found at https://www2.epa.gov/lawsregulations/laws-and-executive-orders.
A. Executive Order 12866: Regulatory
Planning and Review and Executive
Order 13563: Improving Regulation and
Regulatory Review
This action is not a significant
regulatory action and was therefore not
submitted to the Office of Management
and Budget (OMB) for review.
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regulatory actions that concern
environmental health or safety risks that
the EPA has reason to believe may
disproportionately affect children, per
the definition of ‘‘covered regulatory
action’’ in section 2–202 of the
Executive Order. This action is not
subject to Executive Order 13045
because this proposed partial SIP
approval and partial disapproval, if
finalized, will not in-and-of itself create
any new regulations but will simply
disapprove certain state requirements
for inclusion in the SIP.
H. Executive Order 13211: Actions That
Significantly Affect Energy Supply,
Distribution, or Use
This action is not subject to Executive
Order 13211 because it is not a
significant regulatory action under
Executive Order 12866.
I. National Technology Transfer and
Advancement Act (NTTAA)
Section 12(d) of the NTTAA directs
the EPA to use voluntary consensus
standards in its regulatory activities
unless to do so would be inconsistent
with applicable law or otherwise
impractical. The EPA believes that this
action is not subject to the requirements
of section 12(d) of the NTTAA because
application of those requirements would
be inconsistent with the CAA.
J. Executive Order 12898: Federal
Actions To Address Environmental
Justice in Minority Populations and
Low-Income Population
The EPA lacks the discretionary
authority to address environmental
justice in this rulemaking.
List of Subjects in 40 CFR Part 51
Environmental protection, Air
pollution control, Ammonia,
Incorporation by reference,
Intergovernmental relations, Nitrogen
dioxide, Particulate matter, Reporting
and recordkeeping requirements, Sulfur
dioxide, Volatile organic compounds.
Authority: 42 U.S.C. 7401 et seq.
Dated: September 17, 2021.
Deborah Jordan,
Acting Regional Administrator, Region IX.
[FR Doc. 2021–20613 Filed 9–23–21; 8:45 am]
BILLING CODE 6560–50–P
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]]>Agencies
[Federal Register Volume 86, Number 183 (Friday, September 24, 2021)]
[Proposed Rules]
[Pages 53150-53184]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-20613]
[[Page 53149]]
Vol. 86
Friday,
No. 183
September 24, 2021
Part II
Environmental Protection Agency
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40 CFR Part 52
Partial Approval and Partial Disapproval of Air Quality Implementation
Plans and Determination of Attainment by the Attainment Date;
California; San Joaquin Valley Serious Area and Section 189(d) Plan for
Attainment of the 1997 24-Hour PM2.5 NAAQS; Proposed Rule
Federal Register / Vol. 86 , No. 183 / Friday, September 24, 2021 /
Proposed Rules
[[Page 53150]]
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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 52
[EPA-R09-OAR-2021-0261; FRL-8969-01-R9]
Partial Approval and Partial Disapproval of Air Quality
Implementation Plans and Determination of Attainment by the Attainment
Date; California; San Joaquin Valley Serious Area and Section 189(d)
Plan for Attainment of the 1997 24-Hour PM2.5 NAAQS
AGENCY: Environmental Protection Agency (EPA).
ACTION: Proposed rule.
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SUMMARY: The Environmental Protection Agency (EPA) is proposing to
approve in part and disapprove in part portions of a state
implementation plan (SIP) revision submitted by the State of California
to meet Clean Air Act (CAA or ``Act'') requirements for the 1997 24-
hour fine particulate matter (PM2.5) national ambient air
quality standards (NAAQS) in the San Joaquin Valley nonattainment area.
Specifically, the EPA is proposing to approve all but the contingency
measure element of the submitted SIP revision as meeting all applicable
Serious area and CAA section 189(d) requirements for the 1997 24-hour
PM2.5 NAAQS and is proposing disapproval of the contingency
measure element. The EPA is also proposing to determine that the San
Joaquin Valley air quality planning area has attained the 1997 24-hour
PM2.5 NAAQS. This determination is based on sufficient,
quality-assured, and certified data for 2018-2020. Based on our
proposed finding that the San Joaquin Valley nonattainment area has
attained the 1997 24-hour PM2.5 NAAQS, we are proposing to
determine that the requirement for contingency measures will no longer
apply to the San Joaquin Valley nonattainment area for these NAAQS.
Thus, the EPA is proposing to issue a protective finding for
transportation conformity determinations for this proposed disapproval.
DATES: Any comments on this proposal must be received by October 25,
2021.
ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R09-
OAR-2021-0261 at https://www.regulations.gov. For comments submitted at
Regulations.gov, follow the online instructions for submitting
comments. Once submitted, comments cannot be edited or removed from
Regulations.gov. The EPA may publish any comment received to its public
docket. Do not submit electronically any information you consider to be
Confidential Business Information (CBI) or other information whose
disclosure is restricted by statute. Multimedia submissions (e.g.,
audio or video) must be accompanied by a written comment. The written
comment is considered the official comment and should include
discussion of all points you wish to make. The EPA will generally not
consider comments or comment contents located outside of the primary
submission (i.e., on the web, cloud, or other file sharing system). For
additional submission methods, please contact the person identified in
the FOR FURTHER INFORMATION CONTACT section. For the full EPA public
comment policy, information about CBI or multimedia submissions, and
general guidance on making effective comments, please visit https://www.epa.gov/dockets/commenting-epa-dockets. If you need assistance in a
language other than English or if you are a person with disabilities
who needs a reasonable accommodation at no cost to you, please contact
the person identified in the FOR FURTHER INFORMATION CONTACT section.
FOR FURTHER INFORMATION CONTACT: Ashley Graham, Air Planning Office
(ARD-2), EPA Region IX, 75 Hawthorne Street, San Francisco, CA 94105,
(415) 972-3877, or by email at [email protected].
SUPPLEMENTARY INFORMATION: Throughout this document, ``we,'' ``us,'' or
``our'' refer to the EPA.
Table of Contents
I. Background for Proposed Action
A. PM2.5 NAAQS
B. San Joaquin Valley PM2.5 Designations,
Classifications, and SIP Revisions
II. Summary and Completeness Review of the San Joaquin Valley
PM2.5 Plan
A. 2018 PM2.5 Plan
B. Valley State SIP Strategy
III. Clean Air Act Requirements for PM2.5 Serious Area
Plans and for Serious PM2.5 Areas That Fail To Attain
A. Requirements for PM2.5 Serious Area Plans
B. Requirements for Serious PM2.5 Areas That Fail To
Attain
IV. Review of the San Joaquin Valley PM2.5 Plan for the
1997 24-Hour PM2.5 NAAQS
A. Emissions Inventories
B. PM2.5 Precursors
C. Attainment Plan Control Strategy
D. Attainment Demonstration and Modeling
E. Reasonable Further Progress and Quantitative Milestones
F. Contingency Measures
G. Motor Vehicle Emission Budgets
H. Nonattainment New Source Review Requirements Under CAA
Section 189(e)
V. Determination of Attainment by the Attainment Date
A. Requirements for Attainment Determinations
B. Monitoring Network Considerations
C. Data Considerations and Proposed Determination
VI. Summary of Proposed Action and Request for Public Comment
VII. Statutory and Executive Order Reviews
I. Background for Proposed Action
A. PM2.5 NAAQS
Under section 109 of the CAA, the EPA has established NAAQS for
certain pervasive air pollutants (referred to as ``criteria
pollutants'') and conducts periodic reviews of the NAAQS to determine
whether they should be revised or whether new NAAQS should be
established.
On July 18, 1997, the EPA revised the NAAQS for particulate matter
by establishing new NAAQS for particles with an aerodynamic diameter
less than or equal to a nominal 2.5 micrometers (PM2.5).\1\
The EPA established primary and secondary annual and 24-hour standards
for PM2.5.\2\ The annual primary and secondary standards
were set at 15.0 micrograms per cubic meter ([mu]g/m\3\), based on a
three-year average of annual mean PM2.5 concentrations, and
the 24-hour primary and secondary standards were set at 65 [mu]g/m\3\,
based on the three-year average of the 98th percentile of 24-hour
PM2.5 concentrations at each monitoring site within an
area.\3\ Collectively, we refer herein to the 1997 24-hour and annual
PM2.5 NAAQS as the ``1997 PM2.5 NAAQS'' or ``1997
PM2.5 standards.''
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\1\ 62 FR 38652.
\2\ For a given air pollutant, ``primary'' NAAQS are those
determined by the EPA as requisite to protect the public health,
allowing an adequate margin of safety, and ``secondary'' standards
are those determined by the EPA as requisite to protect the public
welfare from any known or anticipated adverse effects associated
with the presence of such air pollutant in the ambient air. See CAA
section 109(b).
\3\ 40 CFR 50.7.
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On October 17, 2006, the EPA revised the level of the 24-hour
PM2.5 NAAQS to 35 [mu]g/m\3\,\4\ and on January 15, 2013,
the EPA revised the level of the primary annual PM2.5 NAAQS
to 12.0 [mu]g/m\3\.\5\ Even though the EPA lowered the 24-hour and
annual PM2.5 NAAQS, the 1997 24-hour PM2.5 NAAQS
remain in effect and the 1997 primary annual PM2.5 NAAQS
remains in effect in areas designated nonattainment for that NAAQS.\6\
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\4\ 71 FR 61144.
\5\ 78 FR 3086.
\6\ 40 CFR 50.13(d).
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The EPA established the 1997 PM2.5 NAAQS after
considering substantial
[[Page 53151]]
evidence from numerous health studies demonstrating that serious health
effects are associated with exposures to PM2.5
concentrations above these levels. Epidemiological studies have shown
statistically significant correlations between elevated
PM2.5 levels and premature mortality. Other important health
effects associated with PM2.5 exposure include aggravation
of respiratory and cardiovascular disease (as indicated by increased
hospital admissions, emergency room visits, absences from school or
work, and restricted activity dates), changes in lung function and
increased respiratory symptoms, and new evidence for more subtle
indicators of cardiovascular health. Individuals particularly sensitive
to PM2.5 exposure include older adults, people with heart
and lung disease, and children.\7\
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\7\ EPA, Air Quality Criteria for Particulate Matter, No. EPA/
600/P-99/002aF and EPA/600/P-99/002bF, October 2004.
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Sources can emit PM2.5 directly into the atmosphere as a
solid or liquid particle (primary PM2.5 or direct
PM2.5), or PM2.5 can form in the atmosphere
(secondary PM2.5) as a result of various chemical reactions
from precursor emissions of nitrogen oxides (NOX), sulfur
oxides (SOX), volatile organic compounds, and ammonia.\8\
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\8\ For example, see 72 FR 20586, 20589 (April 25, 2007).
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B. San Joaquin Valley PM2.5 Designations, Classifications, and SIP
Revisions
Following promulgation of a new or revised NAAQS, the EPA is
required under CAA section 107(d) to designate areas throughout the
nation as attaining or not attaining the NAAQS. Effective April 5,
2005, the EPA established the initial air quality designations for the
1997 24-hour and annual PM2.5 NAAQS, using air quality
monitoring data for the three-year periods of 2001-2003 and 2002-
2004.\9\ The EPA designated the San Joaquin Valley as nonattainment for
both the 1997 24-hour PM2.5 NAAQS (65 [mu]g/m\3\) and the
1997 annual PM2.5 NAAQS (15.0 [mu]g/m\3\).\10\
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\9\ 70 FR 944 (January 5, 2005).
\10\ 40 CFR 81.305.
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The San Joaquin Valley PM2.5 nonattainment area
encompasses over 23,000 square miles and includes all or part of eight
counties: San Joaquin, Stanislaus, Merced, Madera, Fresno, Tulare,
Kings, and the valley portion of Kern.\11\ The area is home to four
million people and is one of the nation's leading agricultural regions.
Stretching over 250 miles from north to south and averaging 80 miles
wide, it is partially enclosed by the Coast Mountain range to the west,
the Tehachapi Mountains to the south, and the Sierra Nevada range to
the east. Under State law, the San Joaquin Valley Unified Air Pollution
Control District (SJVUAPCD or ``District'') has primary responsibility
for developing plans to provide for attainment of the NAAQS in this
area. The District works cooperatively with the California Air
Resources Board (CARB) in preparing attainment plans. Authority for
regulating sources under state jurisdiction in the San Joaquin Valley
is split under State law between the District, which generally has
responsibility for regulating stationary and area sources, and CARB,
which generally has responsibility for regulating mobile sources.
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\11\ For a precise description of the geographic boundaries of
the San Joaquin Valley nonattainment area, see 40 CFR 81.305.
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At the time of the initial designations for the 1997
PM2.5 NAAQS, the EPA interpreted the CAA to require
implementation of the NAAQS under the general nonattainment plan
requirements of subpart 1.\12\ Under subpart 1, states were required to
submit nonattainment plan SIP submissions within three years of the
effective date of designations, that, among other things, provided for
implementation of reasonably available control measures (RACM),
reasonable further progress (RFP), contingency measures, and a modeled
attainment demonstration showing attainment of the NAAQS as
expeditiously as practicable but no later than five years from the
designation (in this instance, no later than April 5, 2010) unless the
state justified an attainment date extension of up to five years.\13\
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\12\ 72 FR 20586.
\13\ CAA sections 172(a)(2), 172(c)(1), 172(c)(2), and
172(c)(9).
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Between 2007 and 2011, California submitted six SIP revisions to
address nonattainment area planning requirements for the 1997 24-hour
and annual PM2.5 NAAQS in the San Joaquin Valley,\14\ which
we refer to collectively as the ``2008 PM2.5 Plan.'' On
November 9, 2011, the EPA approved the portions of the 2008
PM2.5 Plan, as revised in 2009 and 2011, that addressed
attainment of the 1997 24-hour and annual PM2.5 NAAQS in the
San Joaquin Valley PM2.5 nonattainment area, except for the
attainment contingency measures, which we disapproved.\15\ We also
granted the State's request to extend the attainment deadline for the
1997 PM2.5 NAAQS in the San Joaquin Valley to April 5,
2015.\16\
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\14\ 76 FR 69896, n. 2 (November 9, 2011).
\15\ Id. at 69924.
\16\ Id.
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Following a January 4, 2013 decision of the U.S. Court of Appeals
for the D.C. Circuit (``D.C. Circuit'') remanding the EPA's 2007
implementation rule for the 1997 PM2.5 NAAQS,\17\ the EPA
published a final rule on June 2, 2014, classifying the San Joaquin
Valley as a Moderate nonattainment area for the 1997 24-hour and annual
PM2.5 NAAQS under subpart 4, part D of title I of the
Act.\18\ In this action, the EPA acknowledged that states must meet
both subpart 1 and subpart 4 requirements in nonattainment plan SIP
submissions for the 1997 24-hour and annual PM2.5 NAAQS and
provided states with additional time to supplement or withdraw and
resubmit any pending nonattainment plan SIP submissions.
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\17\ Natural Resources Defense Council v. EPA, 706 F.3d. 428
(D.C. Cir. 2013) (``NRDC''). In NRDC, the court held that the EPA
erred in implementing the 1997 PM2.5 standards solely
pursuant to the general implementation requirements of subpart 1,
without also considering the requirements specific to nonattainment
areas for particles less than or equal to 10 [micro]m in diameter
(PM10) in subpart 4, part D of title I of the CAA. The
court reasoned that the plain meaning of the CAA requires
implementation of the 1997 PM2.5 standards under subpart
4 because PM2.5 falls within the statutory definition of
PM10 and is thus subject to the same statutory
requirements as PM10. The court remanded the rule,
without vacatur, and instructed the EPA ``to repromulgate these
rules pursuant to Subpart 4 consistent with this opinion.''
\18\ 79 FR 31566.
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Effective May 7, 2015, the EPA reclassified the San Joaquin Valley
as a Serious nonattainment area for the 1997 PM2.5 NAAQS
based on the determination that the State could not practicably attain
these NAAQS in the San Joaquin Valley nonattainment area by the latest
statutory Moderate area attainment date, i.e., April 5, 2015.\19\ Upon
reclassification as a Serious area, the State became subject to the
requirement of CAA section 188(c)(2) to attain the 1997
PM2.5 NAAQS, as expeditiously as practicable but no later
than ten years after designation, i.e., by no later than December 31,
2015. California submitted its 1997 PM2.5 Serious area plan
for the San Joaquin Valley in two submissions dated June 25, 2015 and
August 13, 2015, including a request under section 188(e) to extend the
attainment date for the 1997 24-hour PM2.5 NAAQS by three
years (to December 31, 2018) and to extend the attainment date for the
1997 annual PM2.5 NAAQS by five years (to December 31,
2020). On February 9, 2016, the EPA proposed to approve most of the
Serious area plan and to
[[Page 53152]]
grant the State's request for extensions of the December 31, 2015
attainment date.\20\ However, on October 6, 2016, after considering
public comments, the EPA denied California's request for these
extensions of the attainment dates.\21\ Consequently, on November 23,
2016, the EPA determined that the San Joaquin Valley had failed to
attain the 1997 24-hour and annual PM2.5 NAAQS by the
December 31, 2015 Serious area attainment date.\22\ This determination
triggered a requirement for California to submit a new SIP submission
for the 1997 24-hour and annual PM2.5 NAAQS for the San
Joaquin Valley that satisfies the requirements of CAA section 189(d).
The statutory deadline for this additional SIP submission was December
31, 2016. The EPA did not finalize the actions proposed on February 9,
2016, with respect to the submitted Serious area plan.\23\
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\19\ 80 FR 18528 (April 7, 2015).
\20\ 81 FR 6936. California's request for extension of the
Serious Area attainment date for the San Joaquin Valley accompanied
its Serious Area attainment plan for the 1997 PM2.5 NAAQS
and related motor vehicle emission budgets, submitted June 25, 2015
and August 13, 2015, respectively.
\21\ 81 FR 69396.
\22\ 81 FR 84481.
\23\ 81 FR 69396, 69400.
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On December 6, 2018, the EPA determined that California had failed
to submit a complete section 189(d) attainment plan for the 1997 24-
hour and annual PM2.5 NAAQS, among other required SIP
submissions for the San Joaquin Valley, by the statutory deadlines.\24\
This finding, which became effective on January 7, 2019, triggered
clocks under CAA section 179(a) for the application of emissions offset
sanctions 18 months after the finding, and highway funding sanctions 6
months thereafter, unless the EPA affirmatively determined that the
State has made a complete SIP submission addressing the identified
failure to submit deficiencies.\25\ The finding also triggered the
obligation under CAA section 110(c) for the EPA to promulgate a federal
implementation plan no later than two years after the finding, unless
the State has submitted, and the EPA has approved, the required SIP
submission.\26\
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\24\ 83 FR 62720.
\25\ Id. at 62723.
\26\ Id.
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On May 10, 2019, CARB made SIP submissions intended to address the
Serious area nonattainment plan and CAA section 189(d) requirements for
the 1997 24-hour and annual PM2.5 NAAQS, among other
requirements for the 2006 and 2012 PM2.5 NAAQS.\27\ CARB
clarified in its May 10, 2019 letter that these new SIP submissions
superseded past submissions to the EPA that the agency had not yet
acted on for the 1997 PM2.5 NAAQS, including the 2015
Serious area attainment plan submissions. On June 24, 2020, the EPA
issued a letter finding these submissions complete and terminating the
sanctions clocks under CAA section 179(a).\28\ The portions of these
SIP submissions that pertain to the 1997 24-hour PM2.5 NAAQS
are the subject of this proposal.
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\27\ Letter dated May 9, 2019, from Richard Corey, Executive
Officer, CARB, to Mike Stoker, Regional Administrator, EPA Region 9.
The letter clarifies that the 2018 PM2.5 Plan supersedes
past submittals to the EPA that the agency has not yet acted on for
the 1997 PM2.5 standards, including the 2015 Plan for the
1997 Standard (submitted by CARB on June 25, 2015) and motor vehicle
emission budgets (submitted by CARB August 13, 2015).
\28\ Letter dated June 24, 2020, from Elizabeth J. Adams,
Director, Air and Radiation Division, EPA Region IX, to Richard
Corey, Executive Officer, CARB, Subject: ``RE: Completeness Finding
for State Implementation Plan (SIP) Submissions for San Joaquin
Valley for the 1997, 2006, and 2012 Fine Particulate Matter
(PM2.5) National Ambient Air Quality Standards (NAAQS)
and Termination of Clean Air Act (CAA) Sanction Clocks.''
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II. Summary and Completeness Review of the San Joaquin Valley
PM[bdi2].[bdi5] Plan
The EPA is proposing action on portions of two SIP submissions made
by CARB to address nonattainment plan requirements for the 1997 24-hour
PM2.5 NAAQS in the San Joaquin Valley. Specifically, the EPA
is proposing to act on those portions of the following two SIP
submissions that pertain to the 1997 24-hour PM2.5 NAAQS:
(i) The ``2018 Plan for the 1997, 2006, and 2012 PM2.5
Standards,'' adopted by the SJVUAPCD on November 15, 2018, and by CARB
on January 24, 2019 (``2018 PM2.5 Plan''); \29\ and (ii) the
``San Joaquin Valley Supplement to the 2016 State Strategy for the
State Implementation Plan,'' adopted by CARB on October 25, 2018
(``Valley State SIP Strategy''). CARB submitted the 2018
PM2.5 Plan and Valley State SIP Strategy to the EPA as a
revision to the California SIP on May 10, 2019.\30\ We refer to these
two SIP submissions collectively as the ``SJV PM2.5 Plan''
or ``Plan.''
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\29\ The 2018 PM2.5 Plan was developed jointly by
CARB and the District.
\30\ Letter dated May 9, 2019, from Richard Corey, Executive
Officer, CARB, to Mike Stoker, Regional Administrator, EPA Region 9.
The EPA previously acted on those portions of the ``2018 Plan for
the 1997, 2006, and 2012 PM2.5 Standards'' and the ``San
Joaquin Valley Supplement to the 2016 State Strategy for the State
Implementation Plan'' that pertain to the 2006 PM2.5
NAAQS (85 FR 44192, July 22, 2020), and proposed action on those
portions pertaining to the 1997 annual PM2.5 NAAQS (86 FR
38652, July 22, 2021) and 2012 annual PM2.5 NAAQS (86 FR
49100, September 1, 2021). The EPA is not, at this time, taking any
action on those portions that pertain to the 1997 annual
PM2.5 NAAQS or the 2012 annual PM2.5 NAAQS. We
intend to act on these portions of the submitted SIP revisions in
subsequent rulemakings.
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The SJV PM2.5 Plan addresses the Serious area
nonattainment plan and CAA section 189(d) requirements for the 1997 24-
hour and annual PM2.5 NAAQS in the San Joaquin Valley,
including the State's demonstration that the area would attain the 1997
24-hour PM2.5 NAAQS by December 31, 2020. In this proposal,
the EPA is proposing action only on those portions of the SJV
PM2.5 Plan that pertain to the 1997 24-hour PM2.5
NAAQS. The EPA is acting on the portions of the SJV PM2.5
Plan that pertain to the 1997 annual PM2.5 NAAQS and
subsequent PM2.5 NAAQS in separate rulemakings.
CAA sections 110(a)(1) and (2) and 110(l) require each state to
provide reasonable public notice and opportunity for public hearing
prior to the adoption and submission of a SIP or SIP revision to the
EPA. To meet this requirement, every SIP submission must include
evidence that the state provided adequate public notice and an
opportunity for a public hearing consistent with the EPA's implementing
regulations in 40 CFR 51.102.
CAA section 110(k)(1)(B) requires the EPA to determine whether a
SIP submission is complete within 60 days of receipt. This section also
provides that any plan that the EPA has not affirmatively determined to
be complete or incomplete will become complete by operation of law six
months after the date of submission. The EPA's SIP completeness
criteria are found in 40 CFR part 51, Appendix V.
A. 2018 PM2.5 Plan
The following portions of the 2018 PM2.5 Plan and
related support documents address both the Serious area nonattainment
plan requirements in CAA section 189(b) and the CAA section 189(d)
requirements for the 1997 24-hour PM2.5 NAAQS in the San
Joaquin Valley: (i) Chapter 4 (``Attainment Strategy for
PM2.5''); (ii) Chapter 5 (``Demonstration of Federal
Requirements for 1997 PM2.5 Standards''); \31\ (iii)
numerous appendices to the 2018 PM2.5 Plan; (iv)
[[Page 53153]]
CARB's ``Staff Report, Review of the San Joaquin Valley 2018 Plan for
the 1997, 2006, and 2012 PM2.5 Standards,'' release date
December 21, 2018 (``CARB Staff Report''); \32\ and (v) the State's and
District's board resolutions adopting the 2018 PM2.5 Plan
(CARB Resolution 19-1 and SJVUAPCD Governing Board Resolution 18-11-
16).\33\
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\31\ Chapter 6 (``Demonstration of Federal Requirements for the
2006 PM2.5 Standard: Serious Plan and Extension
Request'') and Chapter 7 (``Demonstration of Federal Requirements
for the 2012 PM2.5 Standard'') of the 2018
PM2.5 Plan pertain to the 2006 PM2.5 NAAQS and
the 2012 PM2.5 NAAQS, respectively. The EPA previously
acted on those portions of the Plan that pertain to the 2006
PM2.5 NAAQS (85 FR 44192), and proposed action on those
portions pertaining to the 2012 annual PM2.5 NAAQS (86 FR
49100). The EPA intends to take further action on those portions
that pertain to the 2012 annual PM2.5 NAAQS in separate
rulemakings.
\32\ Letter dated December 11, 2019, from Richard Corey,
Executive Officer, CARB, to Mike Stoker, Regional Administrator, EPA
Region 9, transmitting the CARB Staff Report [on the 2018
PM2.5 Plan]. The CARB Staff Report includes CARB's review
of, among other things, the 2018 PM2.5 Plan's control
strategy and attainment demonstration.
\33\ CARB Resolution 19-1, ``2018 PM2.5 State
Implementation Plan for the San Joaquin Valley,'' January 24, 2019,
and SJVUAPCD Governing Board Resolution 18-11-16, ``Adopting the
[SJVUAPCD] 2018 Plan for the 1997, 2006, and 2012 PM2.5
Standards,'' November 15, 2018.
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The appendices to the 2018 PM2.5 Plan that address the
requirements for the 1997 24-hour PM2.5 NAAQS include: (i)
Appendix A (``Ambient PM2.5 Data Analysis''); (ii) Appendix
B (``Emissions Inventory''); (iii) Appendix C (``Stationary Source
Control Measure Analyses''); (iv) Appendix D (``Mobile Source Control
Measure Analyses''); (v) Appendix G (``Precursor Demonstration''); (vi)
Appendix H (``RFP, Quantitative Milestones, and Contingency''); \34\
(vii) Appendix I (``New Source Review and Emission Reduction
Credits''); (viii) Appendix J (``Modeling Emission Inventory''); (ix)
Appendix K (``Modeling Attainment Demonstration''); and (x) Appendix L
(``Modeling Protocol'').
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\34\ Appendix H to 2018 PM2.5 Plan, submitted
February 11, 2020 via the EPA State Planning Electronic
Collaboration System. Following the identification of a
transcription error in the RFP tables of Appendix H, on February 11,
2020, the State submitted a revised version of Appendix H that
corrects the transcription error and provides additional information
on the RFP demonstration. All references to Appendix H in this
proposed rule are to the revised version submitted on February 11,
2020, which replaces the version submitted with the 2018
PM2.5 Plan on May 10, 2019.
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The District provided public notice and opportunity for public
comment prior to its November 15, 2018 public hearing on and adoption
of the 2018 PM2.5 Plan.\35\ CARB also provided public notice
and opportunity for public comment prior to its January 24, 2019 public
hearing on and adoption of the 2018 PM2.5 Plan.\36\ The SIP
submission includes proof of publication of notices for the respective
public hearings. It also includes copies of the written and oral
comments received during the State's and District's public review
processes and the agencies' responses thereto.\37\ Therefore, we find
that the 2018 PM2.5 Plan meets the procedural requirements
for public notice and hearing in CAA sections 110(a) and 110(l) and 40
CFR 51.102. The 2018 PM2.5 Plan became complete by operation
of law on November 10, 2019.
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\35\ SJVUAPCD, ``Notice of Public Hearing for Adoption of
Proposed 2018 PM2.5 Plan for the 1997, 2006, and 2012
Standards,'' October 16, 2018, and SJVUAPCD Governing Board
Resolution 18-11-16.
\36\ CARB, ``Notice of Public Meeting to Consider the 2018
PM2.5 State Implementation Plan for the San Joaquin
Valley,'' December 21, 2018, and CARB Resolution 19-1.
\37\ CARB, ``Board Meeting Comments Log,'' March 29, 2019; J&K
Court Reporting, LLC, ``Meeting, State of California Air Resources
Board,'' January 24, 2019 (transcript of CARB's public hearing), and
2018 PM2.5 Plan, Appendix M (``Summary of Significant
Comments and Responses'').
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B. Valley State SIP Strategy
CARB developed the ``Revised Proposed 2016 State Strategy for the
State Implementation Plan'' (``2016 State Strategy'') to support
attainment planning in the San Joaquin Valley and Los Angeles-South
Coast Air Basin (``South Coast'') ozone nonattainment areas.\38\ In its
resolution adopting the 2016 State Strategy (CARB Resolution 17-7), the
Board found that the 2016 State Strategy would achieve 6 tons per day
(tpd) of NOX emissions reductions and 0.1 tpd of direct
PM2.5 emissions reductions in the San Joaquin Valley by 2025
and directed CARB staff to work with the SJVUAPCD to identify
additional reductions from sources under District regulatory authority
as part of a comprehensive plan to attain all of the PM2.5
NAAQS in the San Joaquin Valley and to return to the Board with a
commitment to achieve additional emissions reductions from mobile
sources.\39\
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\38\ The EPA has approved certain commitments made by CARB in
the 2016 State Strategy for purposes of attaining the ozone NAAQS in
the San Joaquin Valley and South Coast ozone nonattainment areas
(see, e.g., 84 FR 3302 (February 12, 2019) and 84 FR 52005 (October
1, 2019)) and for attaining the 2006 PM2.5 NAAQS in the
San Joaquin Valley (85 FR 44192).
\39\ CARB Resolution 17-7, ``2016 State Strategy for the State
Implementation Plan,'' March 23, 2017, 6-7.
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CARB responded to this resolution by developing and adopting the
``San Joaquin Valley Supplement to the 2016 State Strategy for the
State Implementation Plan'' (``Valley State SIP Strategy'') to support
the 2018 PM2.5 Plan. The State's May 10, 2019 SIP submission
incorporates by reference the Valley State SIP Strategy as adopted by
CARB on October 25, 2018 and submitted to the EPA on November 16,
2018.\40\
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\40\ Letter dated May 9, 2019, from Richard Corey, Executive
Officer, CARB, to Mike Stoker, Regional Administrator, EPA Region 9.
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The Valley State SIP Strategy includes an ``Introduction'' (Chapter
1), a chapter on ``Measures'' (Chapter 2), and a ``Supplemental State
Commitment from the Proposed State Measures for the Valley'' (Chapter
3). Much of the content of the Valley State SIP Strategy is reproduced
in Chapter 4 (``Attainment Strategy for PM2.5'') of the 2018
PM2.5 Plan.\41\ The Valley State SIP Strategy also includes
CARB Resolution 18-49, which, among other things, commits CARB to
achieve specific amounts of NOX and PM2.5
emissions reductions by specific years, for purposes of attaining the
PM2.5 NAAQS in the San Joaquin Valley.\42\
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\41\ For example, Table 2 (proposed mobile source measures and
schedule), Table 3 (emissions reductions from proposed mobile source
measures), and Table 4 (summary of emission reduction measures) of
the Valley State SIP Strategy correspond to tables 4-8, 4-9, and 4-
7, respectively, of the 2018 PM2.5 Plan, Chapter 4.
\42\ CARB Resolution 18-49, ``San Joaquin Valley Supplement to
the 2016 State Strategy for the State Implementation Plan,'' October
25, 2018, 5.
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CARB provided the required public notice and opportunity for public
comment prior to its October 25, 2018 public hearing on and adoption of
the Valley State SIP Strategy.\43\ The SIP submission includes proof of
publication of the public notice for this public hearing. It also
includes copies of the written and oral comments received during the
State's public review process and CARB's responses thereto.\44\
Therefore, we find that the Valley State SIP Strategy meets the
procedural requirements for public notice and hearing in CAA sections
110(a) and 110(l) and 40 CFR 51.102. The Valley State SIP Strategy
became complete by operation of law on November 10, 2019.
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\43\ CARB, ``Notice of Public Meeting to Consider the San
Joaquin Valley Supplement to the 2016 State Strategy for the State
Implementation Plan,'' September 21, 2018, and CARB Resolution 18-
49.
\44\ CARB, ``Board Meeting Comments Log,'' November 2, 2018 and
compilation of written comments; and J&K Court Reporting, LLC,
``Meeting, State of California Air Resources Board,'' October 25,
2018 (transcript of CARB's public hearing).
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III. Clean Air Act Requirements for PM[bdi2].[bdi5] Serious
Area Plans and for Serious PM[bdi2].[bdi5] Areas That Fail
To Attain
A. Requirements for PM2.5 Serious Area Plans
Upon reclassification of a Moderate nonattainment area as a Serious
nonattainment area under subpart 4 of part D, title I of the CAA, the
Act requires the state to make a SIP submission that addresses the
following Serious nonattainment area requirements: \45\
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\45\ 40 CFR 51.1003(b)(1); 81 FR 58010, 58074-58075 (August 24,
2016).
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1. A comprehensive, accurate, current inventory of actual emissions
from all sources of PM2.5 and PM2.5 precursors in
the area (CAA section 172(c)(3));
[[Page 53154]]
2. Provisions to assure that the best available control measures
(BACM), including best available control technology (BACT), for the
control of direct PM2.5 and PM2.5 precursors
shall be implemented no later than four years after the area is
reclassified (CAA section 189(b)(1)(B));
3. A demonstration (including air quality modeling) that the plan
provides for attainment as expeditiously as practicable but no later
than the end of the tenth calendar year after designation as a
nonattainment area (i.e., December 31, 2015, for the San Joaquin Valley
for the 1997 PM2.5 NAAQS);
4. Plan provisions that require RFP (CAA section 172(c)(2));
5. Quantitative milestones that are to be achieved every three
years until the area is redesignated attainment and that demonstrate
RFP toward attainment by the applicable date (CAA section 189(c));
6. Provisions to assure that control requirements applicable to
major stationary sources of PM2.5 also apply to major
stationary sources of PM2.5 precursors, except where the
state demonstrates to the EPA's satisfaction that such sources do not
contribute significantly to PM2.5 levels that exceed the
standard in the area (CAA section 189(e)); \46\
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\46\ As discussed in section IV.H, California submitted
nonattainment NSR SIP revisions to address the subpart 4
requirements for the San Joaquin Valley Serious PM2.5
nonattainment area on November 20, 2019. We are not proposing any
action on this submission at this time. We will act on this
submission through a separate rulemaking, as appropriate.
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7. Contingency measures to be implemented if the area fails to meet
RFP or to attain by the applicable attainment date (CAA section
172(c)(9)); and
8. A revision to the nonattainment new source review (NSR) program
to lower the applicable ``major stationary source'' \47\ thresholds
from 100 tons per year (tpy) to 70 tpy (CAA section 189(b)(3)).
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\47\ For any Serious area, the terms ``major source'' and
``major stationary source'' include any stationary source that emits
or has the potential to emit at least 70 tons per year of
PM2.5. CAA section 189(b)(3) and 40 CFR
51.165(a)(1)(iv)(A)(1)(vii) and (viii) (defining ``major stationary
source'' in serious PM2.5 nonattainment areas).
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Serious area plans must also satisfy the requirements for Moderate
area plans in CAA section 189(a), to the extent the state has not
already met those requirements in the Moderate area plan submitted for
the area.\48\ In addition, the Serious area plan must meet the general
requirements applicable to all SIP submissions under section 110 of the
CAA, including the requirement to provide necessary assurances that the
implementing agencies have adequate personnel, funding, and authority
under section 110(a)(2)(E); and the requirements concerning enforcement
provisions in section 110(a)(2)(C).
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\48\ Because the EPA has not previously approved a SIP
submission for the San Joaquin Valley as meeting the subpart 4 RACM
Moderate area planning requirement under CAA section 189 for the
1997 24-hour PM2.5 NAAQS, the EPA is evaluating relevant
portions of the SJV PM2.5 Plan for compliance with these
requirements, in addition to the requirements of CAA sections 189(b)
and 189(d).
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B. Requirements for Serious PM2.5 Areas That Fail To Attain
In the event that a Serious area fails to attain the
PM2.5 NAAQS by the applicable attainment date, CAA section
189(d) requires that ``the State in which such area is located shall,
after notice and opportunity for public comment, submit within 12
months after the applicable attainment date, plan revisions which
provide for attainment of the . . . standard . . .'' An attainment plan
under section 189(d) must, among other things, demonstrate expeditious
attainment of the NAAQS within the time period provided under CAA
section 179(d)(3) and provide for annual reductions in emissions of
direct PM2.5 or a PM2.5 plan precursor pollutant
within the area of not less than five percent per year from the most
recent emissions inventory for the area until attainment.\49\ In
addition to the requirement to submit control measures providing for a
five percent reduction in emissions of certain pollutants on an annual
basis, the EPA interprets CAA section 189(d) as requiring a state to
submit an attainment plan that includes the same basic statutory plan
elements that are required for other attainment plans.\50\
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\49\ CAA section 189(d), 40 CFR 51.1004(a)(3), 40 CFR
51.1010(c).
\50\ 81 FR 58010, 58098.
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Specifically, a state must submit to the EPA its plan to meet the
requirements of CAA section 189(d) in the form of a complete attainment
plan submission that includes the following elements: \51\
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\51\ 40 CFR 51.1003(c)(1).
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1. A comprehensive, accurate, current inventory of actual emissions
from all sources of PM2.5 and PM2.5 precursors in
the area;
2. A Serious area plan control strategy that ensures that BACM,
including BACT, for the control of direct PM2.5 and
PM2.5 precursors are implemented in the area;
3. Additional measures (beyond those already adopted in previous
nonattainment plan SIP submissions for the area as RACM/RACT, BACM/
BACT, and most stringent measures (MSM) (if applicable)) \52\ that
provide for attainment of the NAAQS as expeditiously as practicable
and, from the date of such submission until attainment, demonstrate
that the plan will at a minimum achieve an annual five percent
reduction in emissions of direct PM2.5 or any
PM2.5 plan precursor;
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\52\ MSM is applicable if the EPA has previously granted an
extension of the attainment date under CAA section 188(e) for the
nonattainment area and NAAQS at issue.
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4. A demonstration (including air quality modeling) that the plan
provides for attainment of the NAAQS at issue as expeditiously as
practicable;
5. Plan provisions that require RFP;
6. Quantitative milestones that the state is to meet every three
years until the area is redesignated attainment and that demonstrate
RFP toward attainment by the applicable date;
7. Contingency measures to be implemented if the state fails to
meet any requirement concerning RFP or quantitative milestones or to
attain the NAAQS at issue by the applicable attainment date; and
8. Provisions to assure that control requirements applicable to
major stationary sources of PM2.5, also apply to major
stationary sources of PM2.5 precursors, except where the
state demonstrates to the EPA's satisfaction that such sources do not
contribute significantly to PM2.5 levels that exceed the
NAAQS at issue in the area.\53\
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\53\ As discussed in section IV.H, California submitted
nonattainment NSR SIP revisions to address the subpart 4
requirements for the San Joaquin Valley Serious PM2.5
nonattainment area on November 20, 2019. We are not proposing any
action on this submission at this time. We will act on this
submission through a separate rulemaking, as appropriate.
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A state's section 189(d) plan submission must demonstrate
attainment as expeditiously as practicable, and no later than five
years from the date of the EPA's determination that the area failed to
attain, consistent with sections 179(d)(3) and 172(a)(2) of the
CAA.\54\
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\54\ 81 FR 84481, 84482.
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A state with a Serious PM2.5 nonattainment area that
fails to attain the NAAQS by the applicable Serious area attainment
date must also address any statutory requirements applicable to
Moderate and Serious nonattainment area plans under CAA sections 172
and 189 of the CAA to the extent that those requirements have not
already been met.\55\ Because the EPA has not previously approved a SIP
submission
[[Page 53155]]
for the San Joaquin Valley as meeting the subpart 4 RACM Moderate area
planning requirements under CAA section 189 for the 1997 24-hour
PM2.5 NAAQS, the EPA is evaluating relevant portions of the
SJV PM2.5 Plan for compliance with this requirement. In
addition, as discussed above, the EPA has not previously approved a SIP
submission for the San Joaquin Valley as meeting the Serious area
planning requirements under CAA section 189(b)(1) for the 1997 24-hour
PM2.5 NAAQS. Some Serious area planning requirements operate
on a timeline that is based on the outermost statutory Serious area
attainment date of the end of the tenth calendar year following the
area's designation to nonattainment. Because section 189(d) requires a
state to address any applicable Serious area requirements that the
state has not already met in the area, and the section 189(d)
obligations do not come into effect until an area has failed to attain
the NAAQS by the Serious area attainment date, the EPA proposes that it
should evaluate any previously unmet Serious area planning obligations
based on the current, applicable attainment date appropriate under
section 189(d), and not the original Serious area attainment date.
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\55\ 81 FR 58010, 58098.
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The EPA provided its preliminary views on the CAA's requirements
for particulate matter plans under part D, title I of the Act in the
following guidance documents: (1) ``State Implementation Plans; General
Preamble for the Implementation of Title I of the Clean Air Act
Amendments of 1990'' (``General Preamble''); \56\ (2) ``State
Implementation Plans; General Preamble for the Implementation of Title
I of the Clean Air Act Amendments of 1990; Supplemental'' (``General
Preamble Supplement''); \57\ and (3) ``State Implementation Plans for
Serious PM-10 Nonattainment Areas, and Attainment Date Waivers for PM-
10 Nonattainment Areas Generally; Addendum to the General Preamble for
the Implementation of Title I of the Clean Air Act Amendments of 1990''
(``General Preamble Addendum'').\58\ More recently, in an August 24,
2016 final rule entitled, ``Fine Particulate Matter National Ambient
Air Quality Standards: State Implementation Plan Requirements''
(``PM2.5 SIP Requirements Rule''), the EPA established
regulatory requirements and provided further interpretive guidance on
the statutory SIP requirements that apply to areas designated
nonattainment for the PM2.5 NAAQS.\59\ We discuss these
regulatory requirements and interpretations of the Act as appropriate
in our evaluation of the SJV PM2.5 Plan that follows.
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\56\ 57 FR 13498 (April 16, 1992).
\57\ 57 FR 18070 (April 28, 1992).
\58\ 59 FR 41998 (August 16, 1994).
\59\ 81 FR 58010.
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IV. Review of the San Joaquin Valley PM[bdi2].[bdi5] Plan
for the 1997 24-Hour PM[bdi2].[bdi5] NAAQS
The EPA is evaluating the SJV PM2.5 Plan against the
Serious area requirements for the 1997 24-hour PM2.5 NAAQS
and the section 189(d) requirements for the 1997 24-hour
PM2.5 NAAQS, as laid out in section III of this proposal.
Many requirements for both a Serious area plan and a section 189(d)
plan are structured around the relevant statutory attainment date. The
latest statutory Serious area attainment date for the San Joaquin
Valley area was December 31, 2015.\60\ On November 23, 2016, the EPA
determined that the area failed to attain by the Serious area
attainment date.
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\60\ As discussed in section I.B, California submitted its
Serious area plan for the 1997 24-hour PM2.5 NAAQS in two
submissions dated June 25, 2015 and August 13, 2015, including a
request under section 188(e) to extend the attainment date for the
1997 24-hour PM2.5 NAAQS by three years (to December 31,
2018). On October 6, 2016, the EPA denied the request for an
extension, but did not finalize action on the Serious area plan
submissions. Accordingly, the Serious area attainment date remained
unchanged: As expeditiously as practicable but no later than
December 31, 2015.
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For the purposes of the section 189(d) requirements, the attainment
date is the date by which a state can attain the NAAQS as expeditiously
as practicable, but no later than five years from the publication date
of the final determination of failure to attain.\61\ As discussed in
section IV.D, the SJV PM2.5 Plan projected that attainment
could be achieved in fewer than five years, i.e., by December 31, 2020.
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\61\ CAA section 179(d)(3); 81 FR 84481, 84482. The
determination of failure to attain published on November 23, 2016.
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When the State submitted the SJV PM2.5 Plan in 2019, the
State withdrew its previous Serious area plan that it had developed to
meet the December 31, 2015 Serious area attainment date. Because the
State submitted the SJV PM2.5 Plan after the EPA's finding
that the area had failed to attain by the applicable Serious area
attainment date, the State could not demonstrate in the SJV
PM2.5 Plan that the area would attain by the Serious area
attainment date, nor could it address other requirements based on this
attainment date, such as RFP and quantitative milestones, because many
of the relevant dates had already passed. As described in section III
of this document, in a section 189(d) plan, a state must address any
statutory requirements applicable to Moderate and Serious nonattainment
area plans to the extent that it has not already met those
requirements, but the EPA believes that it should base this evaluation
on the current applicable attainment date under section 189(d). For
example, it would be illogical to require a state to submit a Serious
area modeled attainment demonstration that provided for attainment by
December 31, 2015, after the EPA has already determined based on
monitoring data that the state failed to attain by such date.
For the purposes of our evaluation of the Serious area plan
requirements, although the State is required to submit a Serious area
plan, and it must structure such a plan based on the Serious area
attainment date, it would serve no purpose to evaluate the SJV
PM2.5 Plan against the now-passed Serious area attainment
date by which the area has already failed to attain. For example, RFP
and quantitative milestones normally are dependent upon the attainment
date. Accordingly, because the State must still meet all Serious area
plan requirements, even if doing so later in conjunction with the
section 189(d) plan and its later attainment date, we will evaluate the
State's compliance with the Serious area plan requirements in light of
the later section 189(d) attainment date, as appropriate. Where the
State in the SJV PM2.5 Plan applies the section 189(d)
attainment date to a Serious area requirement, we will note the
statutory Serious area timeline and accept the submission in
fulfillment of the State's Serious area plan obligation, but evaluate
the submission in light of the section 189(d) attainment date.
A. Emissions Inventories
1. Statutory and Regulatory Requirements
CAA section 172(c)(3) requires that each SIP include a
comprehensive, accurate, current inventory of actual emissions from all
sources of the relevant pollutant or pollutants in the nonattainment
area. The EPA discussed the emissions inventory requirements that apply
to PM2.5 nonattainment areas in the PM2.5 SIP
Requirements Rule and codified these requirements in 40 CFR
51.1008.\62\ The EPA has also issued guidance concerning emissions
[[Page 53156]]
inventories for PM2.5 nonattainment areas.\63\
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\62\ Id. at 58098-58099.
\63\ ``Emissions Inventory Guidance for Implementation of Ozone
and Particulate Matter National Ambient Air Quality Standards
(NAAQS) and Regional Haze Regulations,'' U.S. EPA, May 2017
(``Emissions Inventory Guidance''), available at https://www.epa.gov/air-emissions-inventories/air-emissions-inventory-guidance-implementation-ozone-and-particulate.
---------------------------------------------------------------------------
The base year emissions inventory for a Serious area attainment
plan or a CAA section 189(d) plan must provide a state's best estimate
of actual emissions from all sources of the relevant pollutants in the
area, i.e., all emissions that contribute to the formation of a
particular NAAQS pollutant. For the PM2.5 NAAQS, the base
year inventory must include direct PM2.5 emissions,
separately reported filterable and condensable PM2.5
emissions,\64\ and emissions of all chemical precursors to the
formation of secondary PM2.5, i.e., nitrogen oxides
(NOX), sulfur dioxide (SO2), volatile organic
compounds (VOC), and ammonia.\65\
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\64\ The Emissions Inventory Guidance identifies the types of
sources for which the EPA expects states to provide condensable PM
emissions inventories. Emissions Inventory Guidance, section 4.2.1
(``Condensable PM Emissions''), 63-65.
\65\ 40 CFR 51.1008(b)(1) and (c)(1).
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The emissions inventory base year for a Serious area attainment
plan must be one of the three years for which monitoring data were used
to reclassify the area to Serious, or another technically appropriate
year justified by the state in its Serious area SIP submission.\66\ The
emissions inventory base year for a Serious PM2.5
nonattainment area subject to CAA section 189(d) must be one of the
three years for which the EPA used monitored data to determine that the
area failed to attain the PM2.5 NAAQS by the applicable
Serious area attainment date, or another technically appropriate year
justified by the state in its Serious area SIP submission.\67\
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\66\ 40 CFR 51.1008(b)(1).
\67\ 40 CFR 51.1008(c)(1).
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A state's SIP submission must include documentation explaining how
it calculated emissions data for the inventory. In estimating mobile
source emissions, a state should use the latest emissions models and
planning assumptions available at the time the SIP is developed. The
latest EPA-approved version of California's mobile source emission
factor model for estimating tailpipe, brake, and tire wear emissions
from on-road mobile sources that was available during the State's and
District's development of the SJV PM2.5 Plan was
EMFAC2014.\68\ Following CARB's submission of the Plan, the EPA
approved EMFAC2017, the latest revision to this mobile source emissions
model. States are also required to use the EPA's ``Compilation of Air
Pollutant Emission Factors'' (``AP-42'') road dust method for
calculating re-entrained road dust emissions from paved roads.\69\ \70\
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\68\ 80 FR 77337 (December 14, 2015). EMFAC is short for
EMission FACtor. The EPA announced the availability of the EMFAC2014
model, effective on the date of publication in the Federal Register,
for use in state implementation plan development and transportation
conformity in California. Upon that action, EMFAC2014 was required
to be used for all new regional emissions analyses and CO,
PM10, and PM2.5 hot-spot analyses that were
started on or after December 14, 2017, which was the end of the
grace period for using the prior mobile source emissions model,
EMFAC2011.
\69\ The EPA released an update to AP-42 in January 2011 that
revised the equation for estimating paved road dust emissions based
on an updated data regression that included new emissions tests
results. 76 FR 6328 (February 4, 2011). CARB used the revised 2011
AP-42 methodology in developing on-road mobile source emissions; see
https://www.arb.ca.gov/ei/areasrc/fullpdf/full7-9_2016.pdf.
\70\ AP-42 has been published since 1972 as the primary source
of the EPA's emission factor information and is available at https://www.epa.gov/air-emissions-factors-and-quantification/ap-42-compilation-air-emissions-factors. It contains emission factors and
process information for more than 200 air pollution source
categories. A source category is a specific industry sector or group
of similar emitting sources. The emission factors have been
developed and compiled from source test data, material balance
studies, and engineering estimates.
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In addition to the base year inventory submitted to meet the
requirements of CAA section 172(c)(3), the state must also submit a
projected attainment year inventory and emissions projections for each
RFP milestone year.\71\ These future emissions projections are
necessary components of the attainment demonstrations required under
CAA sections 189(b)(1) and 189(d) and the demonstration of RFP required
under section 172(c)(2).\72\ Emissions projections for future years
(referred to in the Plan as ``forecasted inventories'') should account
for, among other things, the ongoing effects of economic growth and
adopted emissions control requirements. The state's SIP submission
should include documentation to explain how the state calculated the
emissions projections. Where a state chooses to allow new major
stationary sources or major modifications to use emissions reduction
credits (ERCs) that were generated through shutdown or curtailed
emissions units occuring before the base year of an attainment plan,
the projected emissions inventory used to develop the attainment
demonstration must explicitly include the emissions from such
previously shutdown or curtailed emissions units.\73\
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\71\ 40 CFR 51.1008 and 51.1012. See also Emissions Inventory
Guidance, section 3 (``SIP Inventory Requirements and
Recommendations'').
\72\ 40 CFR 51.1004, 51.1008, 51.1011, and 51.1012.
\73\ 40 CFR 51.165(a)(3)(ii)(C)(1).
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2. Summary of the State's Submission
The State included summaries of the planning emissions inventories
for direct PM2.5 and PM2.5 precursors
(NOX, SOX,\74\ VOC,\75\ and ammonia) and the
documentation for the inventories for the San Joaquin Valley
PM2.5 nonattainment area in Appendix B (``Emissions
Inventory'') and Appendix I (``New Source Review and Emission Reduction
Credits'') of the 2018 PM2.5 Plan.
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\74\ The SJV PM2.5 Plan generally uses ``sulfur
oxides'' or ``SOX'' in reference to SO2 as a
precursor to the formation of PM2.5. We use
SOX and SO2 interchangeably throughout this
document.
\75\ The SJV PM2.5 Plan generally uses ``reactive
organic gasses'' or ``ROG'' in reference to VOC as a precursor to
the formation of PM2.5. We use ROG and VOC
interchangeably throughout this document.
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CARB and District staff worked together to develop the emissions
inventories for the San Joaquin Valley PM2.5 nonattainment
area. The District worked with operators of the stationary facilities
in the nonattainment area to develop the stationary source emissions
estimates. The responsibility for developing emissions estimates for
area sources such as agricultural burning and paved road dust was
shared by the District and CARB. CARB staff developed the emissions
inventories for both on-road and non-road mobile sources.\76\
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\76\ The EPA regulations refer to ``non-road'' vehicles and
engines whereas CARB regulations refer to ``Other Mobile Sources''
or ``off-road'' vehicles and engines. These terms refer to the same
types of vehicles and engines. We refer herein to such vehicles and
engines as ``non-road'' sources.
---------------------------------------------------------------------------
The Plan includes winter (24-hour) average and annual average daily
emissions inventories for the 2013 base year, which CARB derived from
the 2012 emissions inventory, and estimated emissions for forecasted
years from 2017 through 2028 for the attainment and RFP demonstrations
for the 1997, 2006, and 2012 PM2.5 NAAQS.\77\ In this
proposal, we are proposing action on those winter average and annual
average emissions inventories necessary to support the Serious area and
CAA section 189(d) nonattainment plans for the 1997 24-
[[Page 53157]]
hour PM2.5 NAAQS, i.e., the 2013 base year inventory,
forecasted inventories for the RFP milestone years of 2017, 2020
(attainment year), and 2023 (post-attainment milestone year), and
additional forecasted emissions inventories for 2018 and 2019 to
support the five percent annual emissions reduction demonstration as
required by CAA section 189(d). Each inventory includes emissions from
stationary, area, on-road, and non-road sources.
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\77\ 2018 PM2.5 Plan, Appendix B, B-18 to B-19. The
winter average daily planning inventory corresponds to the months of
November through April, when daily, ambient PM2.5
concentrations are typically highest. The base year inventory is
from the California Emissions Inventory Development and Reporting
System and future year inventories were estimated using the
California Emission Projection Analysis Model (CEPAM), 2016 SIP
Baseline Emission Projections, version 1.05.
---------------------------------------------------------------------------
CARB developed the base year inventories for stationary sources
using actual emissions reports from facility operators. The State
developed the base year emissions inventory for area sources using the
most recent models and methodologies available at the time the State
was developing the Plan.\78\ The Plan also includes background,
methodology, and inventories of condensable and filterable
PM2.5 emissions from stationary point and non-point
combustion sources that are expected to generate condensable
PM2.5.\79\ CARB used EMFAC2014 to estimate on-road motor
vehicle emissions based on transportation activity data from the 2014
Regional Transportation Plan (2014 RTP) adopted by the transportation
planning agencies in the San Joaquin Valley.\80\ Re-entrained paved
road dust emissions were calculated using a CARB methodology consistent
with the EPA's AP-42 road dust methodology.\81\
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\78\ 2018 PM2.5 Plan, Appendix B, section B.2
(``Emissions Inventory Summary and Methodology'').
\79\ Id. at B-42 to B-44.
\80\ Id. at B-37.
\81\ Id. at B-28.
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CARB developed the emissions forecasts by applying growth and
control profiles to the base year inventory. CARB's mobile source
emissions projections take into account predicted activity rates and
vehicle fleet turnover by vehicle model year and adopted controls.\82\
In addition, the Plan states that the District is providing for use of
pre-base year ERCs as offsets by accounting for such ERCs in the
projected 2025 emissions inventory.\83\ The 2018 PM2.5 Plan
identifies growth factors, control factors, and estimated offset use
between 2013 and 2025 for direct PM2.5, NOX,
SOX, and VOC emissions by source category and lists all pre-
base year ERCs issued by the District for PM10,
NOX, SOX, and VOC emissions, by facility.\84\
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\82\ Id. at B-18 and B-19.
\83\ 2018 PM2.5 Plan, Appendix I, I-1 to I-5.
\84\ Id. at tables I-1 to I-5.
---------------------------------------------------------------------------
Table 1 provides a summary of the winter (24-hour) average
inventories in tons per day (tpd) of direct PM2.5 and
PM2.5 precursors for the 2013 base year. Table 2 provides a
summary of annual average inventories of direct PM2.5 and
PM2.5 precursors for the 2013 base year. These annual
average inventories provide the basis for the control measure analysis
and the RFP and attainment demonstrations in the SJV PM2.5
Plan.
Table 1--San Joaquin Valley Winter Average Emissions Inventory for Direct PM2.5 and PM2.5 Precursors for the
2013 Base Year (tpd)
----------------------------------------------------------------------------------------------------------------
Category Direct PM2.5 NOX SOX VOC Ammonia
----------------------------------------------------------------------------------------------------------------
Stationary Sources.............. 8.5 35.0 6.9 86.6 13.9
Area Sources.................... 41.4 11.5 0.5 156.8 291.5
On-Road Mobile Sources.......... 6.4 188.7 0.6 51.1 4.4
Non-Road Mobile Sources......... 4.4 65.3 0.3 27.4 0.0
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Totals a.................... 60.8 300.5 8.4 321.9 309.8
----------------------------------------------------------------------------------------------------------------
Source: 2018 PM2.5 Plan, Appendix B, tables B-1 to B-5.
a Totals reflect disaggregated emissions and may not add exactly as shown here due to rounding.
Table 2--San Joaquin Valley Annual Average Emissions Inventory for Direct PM2.5 and PM2.5 Precursors for the
2013 Base Year (tpd)
----------------------------------------------------------------------------------------------------------------
Direct PM2.5
Category NOX SOX VOC Ammonia
----------------------------------------------------------------------------------------------------------------
Stationary Sources.............. 8.8 38.6 7.2 87.1 13.9
Area Sources.................... 41.5 8.1 0.3 153.4 310.9
On-Road Mobile Sources.......... 6.4 183.1 0.6 49.8 4.4
Non-Road Mobile Sources......... 5.8 87.4 0.3 33.8 0.0
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Totals a.................... 62.5 317.2 8.5 324.1 329.2
----------------------------------------------------------------------------------------------------------------
Source: 2018 PM2.5 Plan, Appendix B, tables B-1 to B-5.
a Totals reflect disaggregated emissions and may not add exactly as shown here due to rounding.
3. The EPA's Review of the State's Submission
We have reviewed the emissions inventories in the SJV
PM2.5 Plan that pertain to the 1997 24-hour PM2.5
NAAQS and the emissions inventory estimation methodologies used by
California for consistency with CAA requirements and the EPA's
guidance. We find that the inventories are based on the most current
and accurate information available to the State and District at the
time they were developing the Plan and inventories, including the
latest version of California's mobile source emissions model that had
been approved by the EPA at the time, EMFAC2014. The inventories
comprehensively address all source categories in the San Joaquin Valley
PM2.5 nonattainment area and are consistent with the EPA's
inventory guidance.
In accordance with 40 CFR 51.1008(b)(1), the 2013 base year is one
of the three years of monitored data with which the EPA reclassified
the San Joaquin Valley area to Serious. Furthermore, in accordance with
40 CFR 51.1008(c)(1), the 2013 base year is one of the three years of
monitored data with which the EPA determined that the San Joaquin
Valley area failed to attain the PM2.5 NAAQS by the
applicable Serious area attainment date for the
[[Page 53158]]
1997 24-hour PM2.5 NAAQS.\85\ The 2013 base year emissions
inventories represent actual annual average emissions of all sources
within the nonattainment area, direct PM2.5 and
PM2.5 precursors are included in the inventories, and
filterable and condensable direct PM2.5 emissions are
identified separately.
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\85\ 81 FR 84481, 84482.
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With respect to future year emissions projections, we have reviewed
the growth and control factors and find them acceptable and thus
conclude that the future baseline emissions projections, which reflect
ongoing emissions reductions from existing (i.e., ``baseline'') control
measures as discussed in section IV.C.2.a, in the SJV PM2.5
Plan reflect appropriate calculation methods and the latest planning
assumptions. Also, as a general matter, the EPA will approve a SIP
submission that takes emissions reduction credit for a control measure
only where the EPA has approved the measure as part of the SIP. Thus,
for example, to take credit for the emissions reductions from newly
adopted or amended District rules for stationary sources, the related
rules must be approved by the EPA into the SIP. Table 1 of the EPA's
``Technical Support Document, San Joaquin Valley PM2.5 Plan
for the 1997 24-hour PM2.5 NAAQS,'' August 2021 (``EPA's
1997 24-hour PM2.5 TSD'') shows District rules with post-
2013 compliance dates that are reflected in the future year baseline
inventories, along with information on the EPA's approval of these
rules, and shows that stationary source emissions reductions assumed by
the SJV PM2.5 Plan for future years are supported by rules
approved as part of the California SIP for the San Joaquin Valley. With
respect to mobile sources, the EPA has taken action in recent years to
approve CARB mobile source regulations into the state-wide portion of
the California SIP. We therefore find that the future year baseline
projections in the SJV PM2.5 Plan are properly supported by
SIP-approved stationary and mobile source measures.\86\
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\86\ The baseline emissions projections in the 2018
PM2.5 Plan assume implementation of CARB's Zero Emissions
Vehicle (ZEV) sales mandate and greenhouse gas (GHG) standards. On
September 27, 2019, the U.S. Department of Transportation and the
EPA (the Agencies) issued a notice of final rulemaking for the Safer
Affordable Fuel-Efficient (SAFE) Vehicles Rule Part One: One
National Program (SAFE I) that, among other things, withdrew the
EPA's 2013 waiver of preemption for the ZEV sales mandate and
vehicle GHG standards. 84 FR 51310. See also proposed SAFE rule at
83 FR 42986 (August 24, 2018). In response to SAFE I, CARB developed
EMFAC off-model adjustment factors to account for anticipated
changes in on-road emissions. On March 12, 2020, the EPA informed
CARB that the EPA considers these adjustment factors to be
acceptable for future use. See letter dated March 12, 2020 from
Elizabeth J. Adams, EPA Region IX, to Steven Cliff, CARB. On April
30, 2020 (85 FR 24174), the Agencies issued a notice of final
rulemaking titled: The Safer Affordable Fuel-Efficient (SAFE)
Vehicles Rule for Model Years 2021-2026 Passenger Cars and Light
Trucks (SAFE II), establishing the federal fuel economy and GHG
vehicle emissions standards based on the August 2018 SAFE proposal.
The effect of both SAFE final rules (SAFE I and SAFE II) on the on-
road vehicle mix in the San Joaquin Valley nonattainment area and on
the resulting vehicular emissions is expected to be minimal during
the timeframe addressed in this SIP revision. Therefore, we
anticipate the SAFE final rules would not materially change the
attainment, RFP, or five percent reductions demonstrations for the
1997 24-hour PM2.5 NAAQS in the SJV PM2.5
Plan.
---------------------------------------------------------------------------
For these reasons, we are proposing to approve the 2013 base year
emissions inventories in the SJV PM2.5 Plan for the 1997 24-
hour PM2.5 NAAQS as meeting the requirements of CAA section
172(c)(3) and 40 CFR 51.1008 for purposes of both the Serious area and
the CAA section 189(d) attainment plans. We are also proposing to find
that the forecasted inventories in the Plan for the years 2017, 2018,
2019, 2020, and 2023 provide an adequate basis for the BACM, RFP, and
the modeled attainment demonstration analyses in the SJV
PM2.5 Plan.
B. PM2.5 Precursors
1. Statutory and Regulatory Requirements
The composition of PM2.5 is complex and highly variable
due in part to the large contribution of secondary PM2.5 to
total fine particle mass in most locations, and to the complexity of
secondary particle formation processes. A large number of possible
chemical reactions, often non-linear in nature, can convert gaseous
NOX, SO2, VOC, and ammonia to PM2.5,
making them precursors to PM2.5.\87\ Formation of secondary
PM2.5 may also depend on atmospheric conditions, including
solar radiation, temperature, and relative humidity, and the
interactions of precursors with preexisting particles and with cloud or
fog droplets.\88\
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\87\ ``Air Quality Criteria for Particulate Matter'' (EPA/600/P-
99/002aF), EPA, October 2004, Chapter 3.
\88\ ``Regulatory Impact Analysis for the Final Revisions to the
National Ambient Air Quality Standards for Particulate Matter''
(EPA/452/R-12-005), EPA, December 2012), 2-1.
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Under subpart 4 of part D, title I of the CAA and the
PM2.5 SIP Requirements Rule, each state containing a
PM2.5 nonattainment area must evaluate all PM2.5
precursors for regulation unless, for any given PM2.5
precursor, the state demonstrates to the Administrator's satisfaction
that such precursor does not contribute significantly to
PM2.5 levels that exceed the NAAQS in the nonattainment
area.\89\ The provisions of subpart 4 do not define the term
``precursor'' for purposes of PM2.5, nor do they explicitly
require the control of any specifically identified PM2.5
precursor. The statutory definition of ``air pollutant,'' however,
provides that the term ``includes any precursors to the formation of
any air pollutant, to the extent the Administrator has identified such
precursor or precursors for the particular purpose for which the term
`air pollutant' is used.'' \90\ The EPA has identified NOX,
SO2, VOC, and ammonia as precursors to the formation of
PM2.5.\91\ Accordingly, the attainment plan requirements of
subpart 4 apply to emissions of all four precursor pollutants and
direct PM2.5 from all types of stationary, area, and mobile
sources, except as otherwise provided in the Act (e.g., CAA section
189(e)).
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\89\ 81 FR 58010, 58017-58020.
\90\ CAA section 302(g).
\91\ 81 FR 58010, 58015.
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Section 189(e) of the Act requires that the control requirements
for major stationary sources of direct PM10 also apply to
major stationary sources of PM10 precursors, except where
the Administrator determines that such sources do not contribute
significantly to PM10 levels that exceed the standard in the
area. Section 189(e) contains the only express exception to the control
requirements under subpart 4 (e.g., requirements for RACM and RACT,
BACM and BACT, MSM, and new source review (NSR)). Although section
189(e) explicitly addresses only major stationary sources, the EPA
interprets the Act as authorizing it also to determine, under
appropriate circumstances, that regulation of specific PM2.5
precursors from other source categories in a given nonattainment area
is not necessary.\92\ For example, under the EPA's longstanding
interpretation of the control requirements that apply to stationary,
area, and mobile sources of PM10 precursors in the
nonattainment area under CAA section 172(c)(1) and subpart 4,\93\ a
state may demonstrate in a SIP submission that control of a certain
precursor pollutant is not necessary because it does not contribute
significantly to ambient PM10 levels in the nonattainment
area and is not needed for attainment.\94\
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\92\ Id. at 58018-58019.
\93\ General Preamble, 13539-13542.
\94\ Courts have upheld this approach to the requirements of
subpart 4 for PM10. See, e.g., Assoc. of Irritated
Residents v. EPA, et al., 423 F.3d 989 (9th Cir. 2005).
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Under the PM2.5 SIP Requirements Rule, a state may elect
to submit to the
[[Page 53159]]
EPA a ``comprehensive precursor demonstration'' for a specific
nonattainment area to show that emissions of a particular precursor
from all existing sources located in the nonattainment area do not
contribute significantly to PM2.5 levels that exceed the
standard in the area.\95\ If the EPA determines that the contribution
of the precursor to PM2.5 levels in the area is not
significant and approves the demonstration, then the state is not
required to control emissions of the relevant precursor from sources in
the attainment plan.\96\
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\95\ 40 CFR 51.1006(a)(1).
\96\ Id.
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In addition, in May 2019, the EPA issued the ``Fine Particulate
Matter (PM2.5) Precursor Demonstration Guidance''
(``PM2.5 Precursor Guidance''),\97\ which provides
recommendations to states for analyzing nonattainment area
PM2.5 emissions and developing such optional precursor
demonstrations, consistent with the PM2.5 SIP Requirements
Rule. The PM2.5 Precursor Guidance builds upon the draft
version of the guidance, released on November 17, 2016 (``Draft
PM2.5 Precursor Guidance''), which CARB referenced in
developing its precursor demonstration in the SJV PM2.5
Plan.\98\ The EPA's recommendations in the PM2.5 Precursor
Guidance are generally consistent with those in the Draft
PM2.5 Precursor Guidance, with some exceptions, including
that the EPA's recommended contribution threshold for the 24-hour
PM2.5 NAAQS changed from 1.3 [micro]g/m\3\ in the draft
guidance to 1.5 [micro]g/m\3\ in the final guidance.\99\
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\97\ ``PM2.5 Precursor Demonstration Guidance,'' EPA-
454/R-19-004, May 2019, including memorandum dated May 30, 2019 from
Scott Mathias, Acting Director, Air Quality Policy Division and
Richard Wayland, Director, Air Quality Assessment Division, Office
of Air Quality Planning and Standards (OAQPS), EPA to Regional Air
Division Directors, Regions 1-10, EPA.
\98\ ``PM2.5 Precursor Demonstration Guidance, Draft
for Public Review and Comments,'' EPA-454/P-16-001, November 17,
2016, including memorandum dated November 17, 2016 from Stephen D.
Page, Director, OAQPS, EPA to Regional Air Division Directors,
Regions 1-10, EPA.
\99\ For the 24-hour PM2.5 NAAQS, the EPA generally
expects that a precursor demonstration showing that the air quality
impact of a given precursor at all relevant locations does not
exceed a contribution threshold of 1.5 [mu]g/m\3\ will be adequate
to exempt sources of that precursor from control requirements.
PM2.5 Precursor Guidance, 17.
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We are evaluating the 1997 24-hour PM2.5 NAAQS portion
of the SJV PM2.5 Plan in accordance with the presumption
embodied within subpart 4, that states address all PM2.5
precursors in the evaluation of potential control measures unless the
state adequately demonstrates that emissions of a particular precursor
or precursors do not contribute significantly to ambient
PM2.5 levels that exceed the PM2.5 NAAQS in the
nonattainment area and are not necessary for attainment. In reviewing
any determination by a state to exclude a PM2.5 precursor
from the required evaluation of potential control measures, we consider
both the magnitude of the precursor's contribution to ambient
PM2.5 concentrations in the nonattainment area and the
sensitivity of ambient PM2.5 concentrations in the area to
reductions in emissions of that precursor.
2. Summary of the State's Submission
The State presents a brief summary of its PM2.5
precursor analysis in Chapter 5 of the 2018 PM2.5 Plan and
the full precursor demonstration in Appendix G (``Precursor
Demonstration'') of the 2018 PM2.5 Plan.\100\ CARB presents
additional modeling results in Appendix K (``Modeling Attainment
Demonstration''), section 5.6 (``PM2.5 Precursor Sensitivity
Analysis''). CARB also provided clarifying information on its precursor
assessment, including an Attachment A to its letter transmitting the
2018 PM2.5 Plan to the EPA \101\ and further clarifications
in five email transmittals.\102\ The CARB Staff Report contains
additional discussion of the role of ammonia in the formation of
ammonium nitrate and the role of VOC in the formation of ammonium
nitrate and secondary organic aerosol.\103\
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\100\ A copy of the contents of Appendix G appears in the CARB
Staff Report, Appendix C4 (``Precursor Demonstrations for Ammonia,
SOX, and ROG'').
\101\ Letter dated May 9, 2019, from Richard Corey, Executive
Officer, CARB, to Michael Stoker, Regional Administrator, EPA Region
9, Attachment A (``Clarifying information for the San Joaquin Valley
2018 Plan regarding model sensitivity related to ammonia and ammonia
controls'').
\102\ Email dated June 20, 2019, from Jeremy Avise, CARB, to
Scott Bohning, EPA Region IX, Subject: ``RE: SJV model disbenefit
from SOX reduction,'' with attachment (``CARB's June 2019
Precursor Clarification''); email dated September 19, 2019, from
Jeremy Avise, CARB, to Scott Bohning, EPA Region IX, Subject: ``FW:
SJV species responses,'' with attachments (``CARB's September 2019
Precursor Clarification''); email dated October 18, 2019, from Laura
Carr, CARB, to Scott Bohning, Jeanhee Hong, and Rory Mays, EPA
Region IX, Subject: ``Clarifying information on ammonia,'' with
attachment ``Clarifying Information on Ammonia'' (``CARB's October
2019 Precursor Clarification''); email dated April 19, 2021, from
Laura Carr, CARB, to Rory Mays, EPA Region IX, Subject: ``Ammonia
update,'' with attachment ``Update on Ammonia in the San Joaquin
Valley'' (``CARB's April 19, 2021 Precursor Clarification''); and
email dated April 26, 2021, from Laura Carr, CARB, to Scott Bohning,
EPA Region IX, Subject: ``RE: Ammonia update,'' with attachment
``Ammonia in San Joaquin Valley'' (``CARB's April 26, 2021 Precursor
Clarification'').
\103\ CARB Staff Report, Appendix C, 9-16. The CARB Staff
Report, Appendix C4 (``Precursor Demonstrations for Ammonia,
SOX, and ROG'') is very similar to the contents of
Appendix G of the 2018 PM2.5 Plan.
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The 2018 PM2.5 Plan provides both concentration-based
and sensitivity-based analyses of precursor contributions to ambient
PM2.5 concentrations in the San Joaquin Valley. The State
supplemented the sensitivity analysis, particularly for ammonia, with
additional information, including factors identified in the
PM2.5 Precursor Guidance, such as emissions trends, the
appropriateness of future year versus base year sensitivity, available
emissions controls, and the severity of nonattainment.\104\ These
analyses led CARB to conclude that direct PM2.5 and
NOX emissions contribute significantly to ambient
PM2.5 levels that exceed the PM2.5 NAAQS in the
San Joaquin Valley while ammonia, SOX, and VOC do not
contribute significantly to such exceedances.\105\ We summarize the
State's analysis and conclusions below. For a more detailed summary of
the precursor demonstration in the Plan, please refer to the EPA's
``Technical Support Document, EPA Evaluation of PM2.5
Precursor Demonstration, San Joaquin Valley PM2.5 Plan for
the 2006 PM2.5 NAAQS,'' February 2020 (``EPA's February 2020
Precursor TSD'').
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\104\ PM2.5 Precursor Guidance, 18-19 (consideration
of additional information), 31 (available emissions controls), and
35-36 (appropriateness of future year versus base year sensitivity).
\105\ Direct PM2.5 emissions are considered a primary
source of ambient PM2.5 (i.e., no further formation in
the atmosphere is required), and therefore is not considered a
precursor pollutant under subpart 4, which may differ from a more
generalized understanding of what contributes to ambient
PM2.5.
---------------------------------------------------------------------------
For direct PM2.5 and NOX, CARB modeled the
sensitivity of ambient PM2.5 in the San Joaquin Valley to a
30 percent reduction in anthropogenic emissions of each pollutant in
2013, 2020, and 2024.\106\ The State concluded that direct
PM2.5 and NOX emissions reductions will continue
to have a significant impact on 24-hour PM2.5 design values
in the San Joaquin Valley, with NOX reductions being
particularly important.\107\ Consistent with this conclusion, the State
focused the control strategy and attainment demonstration on these two
pollutants,
[[Page 53160]]
as described in section IV.C of this preamble.
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\106\ 2018 PM2.5 Plan, Chapter 5, 5-7 to 5-8. CARB
modeled the effects of both NOX reductions and direct
PM2.5 reductions but the direct PM2.5 results
were used only as a point of comparison, as direct PM2.5
emissions must be regulated in all PM2.5 nonattainment
areas.
\107\ Id. at 5-8; and 2018 PM2.5 Plan, Appendix G, 2.
CARB presents its sensitivity analysis for emissions reductions in
direct PM2.5 and NOX in the Plan's attainment
demonstration appendix. 2018 PM2.5 Plan, Appendix K,
Table 47 (annual average design values) and Table 48 (24-hour
average design values).
---------------------------------------------------------------------------
For ammonia, SOX, and VOC, CARB assessed the 2015 annual
average concentration of each precursor in ambient PM2.5 at
Bakersfield, for which the necessary speciated PM2.5 data
are available and where the highest PM2.5 design values have
been recorded in most years, and compared those concentrations to the
recommended annual average contribution threshold of 0.2 [micro]g/m\3\
from the Draft PM2.5 Precursor Guidance, which was available
at the time the State developed the SIP.\108\ The contributions of
ammonia, SOX, and VOC were 5.2 [micro]g/m\3\, 1.6 [micro]g/
m\3\, and 6.2 [micro]g/m\3\, respectively. Given that these levels are
well above the EPA's 0.2 [micro]g/m\3\ recommended contribution
threshold, the State proceeded with a sensitivity-based analysis.
---------------------------------------------------------------------------
\108\ 2018 PM2.5 Plan, Appendix G, 3. The Plan does
not present a concentration-based analysis for the 24-hour average
concentrations in the San Joaquin Valley. Instead, CARB relied on
the annual average concentration-based analysis as an interim step
to the sensitivity-based analysis, for which CARB assessed the
sensitivity of both 24-hour average and annual average ambient
PM2.5 concentrations to precursor emissions reductions.
Separately, the Plan presents a graphical representation of annual
average ambient PM2.5 components (i.e., crustal
particulate matter, elemental carbon, organic matter, ammonium
sulfate, and ammonium nitrate) for 2011-2013 for Bakersfield,
Fresno, and Modesto. 2018 PM2.5 Plan, Chapter 3, 3-3 to
3-4.
---------------------------------------------------------------------------
CARB's sensitivity-based analysis used the same Community
Multiscale Air Quality (CMAQ) modeling platform as that used for the
Plan's attainment demonstration. The State modeled the sensitivity of
ambient PM2.5 concentration in the San Joaquin Valley to 30
percent and 70 percent emissions reductions in 2013, 2020, and 2024 for
each of ammonia, SOX, and VOC. The State estimated baseline
(2013, 2020, and 2024) design values for PM2.5 using
relative response factors (RRFs) and calculated the ammonia,
SOX, and VOC precursor contribution for a given year and for
each sensitivity scenario (30 percent and 70 percent emissions
reductions) as the difference between its baseline design value and the
design value for each sensitivity scenario.\109\
---------------------------------------------------------------------------
\109\ This procedure is the procedure recommended by the EPA.
PM2.5 Precursor Guidance, 37.
---------------------------------------------------------------------------
We summarize the State's sensitivity-based analysis and additional
information in the sections that follow for ammonia, SOX,
and VOC.
a. Ammonia
For ammonia, the State compared the 24-hour precursor contributions
to 1.3 [micro]g/m\3\, the recommended contribution threshold in the
Draft PM2.5 Precursor Guidance. For a modeled 30 percent
ammonia emissions reduction, the ambient PM2.5 responses in
2013 ranged from 0.9 to 3.3 [micro]g/m\3\ across 15 monitoring sites,
with a majority of sites above the 1.3 [micro]g/m\3\ contribution
threshold (and also above the 1.5 [micro]g/m\3\ contribution threshold
in the final PM2.5 Precursor Guidance). PM2.5
responses in 2020 ranged from 0.5 to 1.9 [micro]g/m\3\, with four sites
at or above the 1.3 [micro]g/m\3\ contribution threshold, including one
site above the 1.5 [micro]g/m\3\ contribution threshold in the final
PM2.5 Precursor Guidance. In 2024, all modeled responses
were below both recommended contribution thresholds. For a modeled 70
percent ammonia emissions reduction, the ambient PM2.5
responses in 2013 ranged from 3.5 to 12.4 [micro]g/m\3\, with all
monitoring sites above the 1.3 [micro]g/m\3\ threshold (and above the
1.5 [micro]g/m\3\ threshold), the PM2.5 responses in 2020
ranged from 1.6 to 6.4 [micro]g/m\3\, and the PM2.5
responses in 2024 ranged from 1.2 to 3.0 [micro]g/m\3\, with most sites
above both recommended thresholds. For further detail, please see the
EPA's February 2020 Precursor TSD, Table 2, and the 2018
PM2.5 Plan, Appendix G, tables 2 through 7. In summary, for
a 30 percent ammonia reduction, a majority of sites have
PM2.5 responses above the contribution threshold in the 2013
modeling, decreasing to a single site above the contribution threshold
for 2020, and no sites above the contribution threshold for 2024. For a
70 percent reduction, all sites are above the contribution threshold in
the 2013 and 2020 modeling, and a majority of sites are above the
contribution threshold in 2024.
The State based its ammonia precursor determination on the
sensitivity analysis for the future years, using a 30 percent ammonia
emissions reduction. These choices respectively reflect its assessment
of research studies and the Plan's projected emissions reductions, and
on its assessment of available emissions controls. As explained in the
PM2.5 Precursor Guidance, precursor responses may be above
the recommended contribution threshold and yet not contribute
significantly to levels that exceed the standard in the area.
Therefore, as recommended by the EPA, the State considered additional
information to examine whether the identified PM2.5
responses constituted a significant contribution to ambient
PM2.5 in the San Joaquin Valley. The additional information
included research studies, emissions trends, and information to support
the State's conclusion that a 30 percent ammonia emissions reduction
represented a reasonable upper bound on the ammonia emissions
reductions to model in estimating its contribution to ambient
PM2.5 levels. We summarize this additional information below
and provide a more detailed evaluation in the EPA's February 2020
Precursor TSD.
The State describes previous research that supports its finding
that ammonium nitrate PM2.5 formation is the San Joaquin
Valley is NOX-limited rather than ammonia-limited.\110\
Essentially, ammonia is so abundant in the San Joaquin Valley that even
with large ammonia emissions reductions there would still be enough
ammonia to combine with the available NOX to readily form
particulate ammonium nitrate. Therefore, ammonia emissions reductions
would lead to only small decreases in PM2.5 concentrations.
In contrast, because emissions of NOX are less abundant in
the San Joaquin Valley (i.e., more limited relative to emissions of
ammonia after normalizing for their differing molecular weights), the
PM2.5 concentrations in the atmosphere are more responsive
to reductions in NOX than to reductions of ammonia. Thus,
these analyses indicate that the area is NOX-limited.
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\110\ 2018 PM2.5 Plan, Appendix G, 9-10; CARB Staff
Report, Appendix C, 12-15; and Attachment A to CARB's May 9, 2019
submittal letter.
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The State also points to the conclusions of a study conducted by
Lurmann et al., based on ambient measurements during the winter 2000-
2001 California Regional Particulate Air Quality Study intensive field
study.\111\ That study found that most areas of the San Joaquin Valley
were NOX-limited with respect to ammonium nitrate formation.
Since that time, large additional NOX emissions reductions
have occurred, which would increase the degree to which ammonium
nitrate formation in the San Joaquin Valley is NOX-limited.
Based on more recent aircraft-borne measurements during the 2013
DISCOVER-AQ campaign,\112\ the State similarly concluded that ammonium
nitrate formation is NOX-limited based on the large amount
of ``excess ammonia,'' which is defined as the amount of measured
ammonia left over if all the nitrate and sulfate present
[[Page 53161]]
were to combine with available ammonia to form particulate.\113\ The
CARB Staff Report describes these conclusions in more detail and lists
results from multiple other recent studies with similar
conclusions.\114\ Finally, in a supplemental submittal, CARB described
the results of two analyses confirming the likely underestimation of
ammonia emissions in the modeled emissions inventory inputs.\115\ CARB
compared CMAQ model predictions of ammonia with the 2013 DISCOVER-AQ
aircraft measurements and found ammonia was underpredicted, and noted
that this would result in the response to ammonia reductions being
overpredicted. CARB also compared 2017 satellite measurements of
ammonia with CMAQ model predictions and found that modeled ammonia
concentrations were half of the magnitude of the satellite observations
at some locations, and the modeled valley-wide average was about 25
percent less than observed. Because the modeling performs well for the
various PM2.5 components, as well as for ozone and
NO2,\116\ the CARB finding of CMAQ model underpredictions
for ammonia is consistent with an underestimation of ammonia emissions
inventory input to the model.
---------------------------------------------------------------------------
\111\ Frederick W. Lurmann, Steven G. Brown, Michael C.
McCarthy, and Paul T. Roberts, ``Processes Influencing Secondary
Aerosol Formation in the San Joaquin Valley during Winter,'' Journal
of the Air & Waste Management Association, (2006), 56:12, 1679-1693,
DOI: 10.1080/10473289.2006.10464573.
\112\ Deriving Information on Surface conditions from COlumn and
VERtically Resolved Observations Relevant to Air Quality,'' https://www.nasa.gov/mission_pages/discover-aq/.
\113\ 2018 PM2.5 Plan, Appendix G, Figure 2.
\114\ CARB Staff Report, Appendix C, 12.
\115\ CARB's April 26, 2021 Precursor Clarification.
\116\ EPA's February 2020 Modeling TSD, 21.
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Regarding emissions trends, the CARB Staff Report presents an
emissions inventory-based argument on the relative insensitivity of
PM2.5 to ammonia reductions.\117\ CARB compared the size of
the ammonia and NOX emissions inventories in tons per day,
after normalizing for their differing molecular weights, and found that
ammonia was roughly three times as abundant as NOX in 2013
and is projected to be about six times as abundant in 2025, due to the
continuing decline in NOX emissions (while ammonia emissions
are generally constant into the future).\118\ While the State
recognized that this is only a ``first-level assessment,'' it provides
additional support for the State's conclusion that NOX, and
not ammonia, is the limiting precursor for ammonium nitrate formation,
and that the ammonium nitrate portion of ambient PM2.5 would
be expected to be relatively insensitive to ammonia emissions
reductions. This is also consistent with the ammonia sensitivity
modeling for the San Joaquin Valley, which showed that PM2.5
concentrations will be less sensitive to ammonia reductions as
NOX emissions go down in the future (i.e., the
PM2.5 impacts were much smaller in the 2020 and 2024 future
modeled cases compared to the 2013 base year).
---------------------------------------------------------------------------
\117\ CARB Staff Report, Appendix C, 15.
\118\ Annual average ammonia emissions are projected to decrease
4.6 tpd (1.4 percent) from 2013 to 2024. 2018 PM2.5 Plan,
Appendix B, Table B-5.
---------------------------------------------------------------------------
The State projected that NOX emissions in the San
Joaquin Valley would decrease by 36 percent from 2013 to 2020, and by
53 percent from 2013 to 2024, while ammonia emissions would remain
relatively flat, thereby increasing the relative abundance of
ammonia.\119\ Based on the Plan's emissions reduction projections
combined with the research study conclusions, the State relies on the
modeled responses for the future years, rather than the 2013 base year,
stating that the future year NOX emissions are more
representative of San Joaquin Valley emissions conditions.\120\ The
State references the Draft PM2.5 Precursor Guidance, which
notes that it may be appropriate to model future conditions that are
more representative of current atmospheric conditions and those
conditions expected closer to the attainment date. The State concludes
that this in fact applies to the San Joaquin Valley.\121\
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\119\ 2018 PM2.5 Plan, Appendix G, 8-9.
\120\ Id. at 9.
\121\ Id (referencing Draft PM2.5 Precursor Guidance,
33). See also PM2.5 Precursor Guidance, 35.
---------------------------------------------------------------------------
With respect to the State's selection of 30 percent as an upper
bound on the ammonia reductions to model, the State described its
review of the most important ammonia source categories in the San
Joaquin Valley, existing control measures that affect ammonia emissions
from these sources, additional mitigation options for these sources,
and information provided in the PM2.5 Precursor Guidance
about ammonia reductions achieved nationwide from 2011 to 2017.\122\
The primary sources of ammonia emissions identified in the 2018
PM2.5 Plan are: (1) Confined animal facilities (CAFs); (2)
agricultural fertilizer; (3) biosolids, animal manure, and poultry
litter operations; and (4) organic material composting operations.\123\
CAFs are subject to District Rule 4570; biosolids, animal manure, and
poultry litter operations are subject to District Rule 4565; and
organic material composting operations are subject to District Rule
4566. Although these District rules explicitly apply only to VOC
emissions from these sources, the State concludes that these rules also
reduce ammonia emissions. Appendix C of the 2018 PM2.5 Plan
cites several scientific studies that address the correlation between
VOC and ammonia emissions from these emissions sources.\124\ Based on
these evaluations, the State concludes that ammonia control measures
achieving even the low end of the range (30 percent) are not feasible
for implementation in the San Joaquin Valley and that it is therefore
reasonable to treat a 30 percent ammonia reduction as an upper bound
for modeling in the precursor demonstration.
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\122\ 2018 PM2.5 Plan, Appendix G and Appendix C,
section C-25, and CARB's October 2019 Precursor Clarification.
\123\ 2018 PM2.5 Plan, Appendix C, section C-25.
\124\ Id. at C-314 and following.
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In summary, the State's sensitivity analysis presents a range of
PM2.5 responses to ammonia emissions reductions depending on
base year versus future year, and on the scale of emissions reductions
that may be possible. The Plan provides the State's bases for finding
that the future year sensitivity results better represent conditions in
the San Joaquin Valley than the 2013 base year and for finding a 30
percent ammonia reduction to be a reasonable upper bound for modeled
ammonia emissions reductions in assessing the ammonia contribution.
Based on these analyses, the State concludes that ammonia does not
contribute significantly to ambient PM2.5 levels above the
1997 24-hour PM2.5 NAAQS in the San Joaquin Valley.
b. SOX
For SOX, the State compared the 24-hour precursor
contributions to the recommended draft contribution threshold of 1.3
[micro]g/m\3\ in the Draft PM2.5 Precursor Guidance. For
modeled SOX emissions reductions of 30 percent and 70
percent, the ambient PM2.5 responses in 2013 ranged from -
1.4 to 0.5 [micro]g/m\3\ across 15 monitoring sites, which all fall
below the 1.3 [micro]g/m\3\ draft contribution threshold, and hence
also below the contribution threshold of 1.5 [micro]g/m\3\ in the final
version of the PM2.5 Precursor Guidance.\125\ The response
was below zero at most monitoring sites, indicating an increase, rather
than a decrease, in ambient PM2.5 in response to
SOX emissions reductions (i.e., a disbenefit). Only the
Stockton and Manteca sites had slightly positive responses to 30
percent and 70 percent emissions reductions, and the Tranquillity site
also had a slightly positive response only to a 30 percent reduction.
For the 15 sites, in 2020, the responses to 30 percent and 70 percent
emissions reductions ranged from -1.3 [micro]g/m\3\ to
[[Page 53162]]
0.5 [micro]g/m\3\ while for 2024, the responses ranged from -1.1
[micro]g/m\3\ to 0.6 [micro]g/m\3\; these are also all below the
contribution threshold, with most sites showing a disbenefit from
SOX reductions.\126\ The Stockton, Manteca, and Tranquillity
sites showed the same pattern of slight benefits as for 2013.\127\ For
further detail, please see the EPA's February 2020 Precursor TSD, Table
3 and the 2018 PM2.5 Plan, Appendix G, tables 8 and 9 and
Appendix K, tables 46, 48, and 50.
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\125\ 2018 PM2.5 Plan, Appendix G, Table 8 and Table
9.
\126\ CARB's September 2019 Precursor Clarification, 2020
analysis tables 15 and 16, and 2024 analysis tables 15 and 16.
\127\ 2018 PM2.5 Plan, Appendix K, Table 48 and Table
50.
---------------------------------------------------------------------------
CARB also included additional information regarding emissions
trends and an evaluation of the SOX emissions reduction
disbenefit. We summarize this additional information below and provide
a more detailed evaluation in the EPA's February 2020 Precursor TSD.
In terms of emissions trends, the State found that SOX
emissions decreased from 2013 to 2014 and then were expected to very
gradually rise to 7.8 tpd in 2020 and 8.0 tpd in 2024.\128\ Given that
projected SOX emissions are very similar in 2020 and 2024,
the State concluded that the 2020 and 2024 sensitivity results were
redundant. Comparing the ambient responses in 2013 and 2024, the State
found that the responses were slightly less negative or, for a small
number of sites, slightly higher in 2024, but still no more than 0.6
[micro]g/m\3\ in response to a 70 percent SOX emissions
reduction.\129\ This supports the State's conclusion as to the overall
disbenefit of reducing SOX emissions.
---------------------------------------------------------------------------
\128\ 2018 PM2.5 Plan, Appendix G, Figure 4.
\129\ CARB's September 2019 Precursor Clarification, 2013
analysis Table 16 and 2024 analysis Table 16.
---------------------------------------------------------------------------
To explain the SOX emissions reduction disbenefit that
is observed in some cases, CARB refers to the non-linearity of
inorganic aerosol thermodynamics, as described in a study by West et
al.\130\ That paper discusses how, under certain conditions, reducing
SOX could free ammonia to combine with nitrate, increasing
overall PM2.5 mass. To investigate this issue further, CARB
conducted simulations with the ISORROPIA inorganic aerosol
thermodynamic equilibrium model used within the CMAQ model and provided
clarifications to the EPA.\131\ In essence, CARB states that for some
conditions typical of San Joaquin Valley, ISORROPIA switches to a
different chemical regime in which the disbenefit occurs. CARB states
that it is not known how well this model behavior reflects the actual
atmosphere, but CARB accepts the results because it is a well-known and
widely used chemical model.
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\130\ 2018 PM2.5 Plan, Appendix K, section 5.6
(``PM2.5 Precursor Sensitivity Analysis''); and West,
J.J., Ansari, A.S., Pandis, S.N., 1999, Marginal PM2.5:
Nonlinear aerosol mass response to sulfate reductions in the eastern
United States, Journal of the Air & Waste Management Association,
49, 1415-1424. https://doi.org/10.1080/10473289.1999.10463973.
\131\ CARB's June 2019 Precursor Clarification.
---------------------------------------------------------------------------
Based on the small and mostly negative modeled response of ambient
PM2.5 to SOX emissions reductions, and based on
its scientific understanding of sulfate interactions with other
molecules in the air, the State concludes that SOX does not
contribute significantly to ambient PM2.5 levels that exceed
the 1997 24-hour PM2.5 NAAQS in the San Joaquin Valley.
c. VOC
For VOC, CARB compared the 24-hour precursor contributions to the
EPA's recommended draft contribution threshold of 1.3 [micro]g/m\3\.
For a modeled 30 percent VOC emissions reduction, the ambient
PM2.5 responses in 2013 ranged from 0.1 to 1.9 [micro]g/m\3\
across 15 monitoring sites, with two sites above the 1.3 [micro]g/m\3\
draft contribution threshold.\132\ \133\ The 2020 responses ranged from
-0.1 to 0.6 [micro]g/m\3\, with all monitoring sites below the 1.3
[micro]g/m\3\ draft contribution threshold, and hence also below the
contribution threshold of 1.5 [micro]g/m\3\ that was finalized in the
final PM2.5 Precursor Guidance. The 2024 responses ranged
from -0.4 to 0.0 [micro]g/m\3\, with all monitoring sites below both
the draft and final contribution thresholds. For a 70 percent VOC
emissions reduction, the PM2.5 responses in 2013 ranged from
0.2 to 4.8 [micro]g/m\3\, including responses above both contribution
thresholds at a majority of sites. The 2020 response ranged from -0.2
to 1.5 [micro]g/m\3\, with one site at the final contribution
threshold. The 2024 response ranged from -1.0 to 0.0 [micro]g/m\3\ with
monitoring sites below both the contribution thresholds. In other
words, in response to either a 30 percent or a 70 percent reduction in
VOC emissions, CARB models a decrease in ambient PM2.5
levels at all sites for 2013, whereas for 2020, there were just small
decreases in ambient PM2.5 levels at most sites and an
increase at one site, and for 2024 there were increases in
PM2.5 at all sites, i.e., a disbenefit. For further detail,
please see the EPA's February 2020 Precursor TSD, Table 4, and the 2018
PM2.5 Plan, Appendix G, tables 10 through 15.
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\132\ 2018 PM2.5 Plan, Appendix G, Table 10.
\133\ We note that one site (Visalia) has a modeled response
above the EPA's final recommended contribution threshold of 1.5
[micro]g/m\3\ and one additional site (Bakersfield-California
Avenue) has a modeled response below the 1.5 [micro]g/m\3\ threshold
but above the EPA's draft threshold of 1.3 [micro]g/m\3\.
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CARB then considered additional information to assess whether these
PM2.5 responses constituted a significant contribution to
ambient PM2.5 in the San Joaquin Valley, including emissions
trends and an assessment of the modeled disbenefit of VOC emissions
reductions. Regarding emissions trends, CARB found that VOC emissions
would decrease approximately 30 tpd (or 9 percent) from 2013 to 2024,
with approximately 28 out of the 30 tpd reduction taking place by
2020.\134\ The State concludes that the formation of ambient
PM2.5 from VOC may therefore differ in base and future years
and that the sensitivity analysis for 2013 is not representative of
current or future conditions.
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\134\ 2018 PM2.5 Plan, Appendix G, 19 and Figure 5.
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CARB explained the modeled disbenefit of VOC reductions as follows:
Emissions of VOC and NOX react in the atmosphere to form
organic nitrate species, such as peroxyacetyl nitrate (PAN), meaning
that some portion of the NOX emissions is not available to
react with ammonia to form ammonium nitrate. In other words, VOC
emissions are a ``sink'' for NOX emissions. Reducing VOC
emissions therefore reduces the formation of organic nitrates, so the
sink is smaller and nitrate molecules are freed to react with ammonia
to form particulate ammonium nitrate.\135\ The State further explored
the VOC disbenefit based on a 2016 CARB modeling assessment provided in
Appendix A (``Air Quality Modeling'') of the ``2016 Moderate Area Plan
for the 2012 PM2.5 Standard'' for the San Joaquin Valley
(``2016 PM2.5 Plan''), which CARB submitted to the EPA as a
SIP revision on May 10, 2019.\136\
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\135\ 2018 PM2.5 Plan, Appendix K, 72 (citing Meng,
Z., D. Dabdub, D., Seinfeld, J.H., Chemical Coupling Between
Atmospheric Ozone and Particulate Matter, Science 277, 116 (1997).
DOI: 10.1126/science.277.5322.116).
\136\ 2016 PM2.5 Plan, Appendix A, A-57. See also
2018 PM2.5 Plan, Appendix K, section 5.6
(``PM2.5 Precursor Sensitivity Analysis''), 71-72.
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Based on its sensitivity-based analysis of VOC emissions
reductions, VOC emissions trends, and the scientific understanding of
VOC chemistry in the San Joaquin Valley, CARB concludes that VOC
emissions do not contribute significantly to PM2.5 levels
that exceed the 1997 24-hour PM2.5 NAAQS in the San Joaquin
Valley.
[[Page 53163]]
3. The EPA's Review of the State's Submission
The EPA has evaluated the State's precursor demonstration
consistent with the PM2.5 SIP Requirements Rule and the
recommendations in the PM2.5 Precursor Guidance. Based on
this evaluation, the EPA agrees that NOX emissions
contribute significantly to ambient PM2.5 levels that exceed
the 1997 24-hour PM2.5 NAAQS in the San Joaquin Valley and
that NOX emissions sources, therefore, remain subject to
control requirements under subparts 1 and 4 of the part D, title I of
the Act. For the reasons provided below, the EPA proposes to approve
the State's demonstration that ammonia, SOX, and VOC
emissions do not contribute significantly to ambient PM2.5
levels that exceed the 1997 24-hour PM2.5 NAAQS in the San
Joaquin Valley.
Regarding the State's analytical approach, the EPA finds that the
State based its analyses on the latest available data and studies
concerning ambient PM2.5 formation in the San Joaquin Valley
from precursor emissions. Regarding the required concentration-based
analysis, the EPA finds that the State assessed the absolute annual
average contribution of each precursor in ambient PM2.5
(i.e., in 2015). On the basis of the absolute concentrations being well
above the EPA's recommended contribution thresholds for both the 24-
hour and annual average NAAQS, the State proceeded with its
sensitivity-based analysis, which is the recommended sequence under the
final PM2.5 Precursor Guidance.\137\
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\137\ For further discussion of the EPA's evaluation of the
State's concentration-based analysis, see the EPA's February 2020
Precursor TSD, sections entitled ``Concentration-based analysis''
within the EPA's evaluation for each of ammonia, SOX, and
VOC.
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With respect to the sensitivity-based analysis, we find that the
State performed its analyses following the steps of the EPA's
recommended approach--i.e., for each modeled year and percent precursor
emissions reduction, the State estimated the ambient PM2.5
response using the procedure recommended in the PM2.5
Precursor Guidance and compared the result to the recommended
contribution threshold. The EPA also finds that the performance of the
photochemical model was adequate for use in estimating the ambient
PM2.5 responses, as discussed in section J (``Air Quality
Model Performance'') of the EPA's ``Technical Support Document, EPA
Evaluation of Air Quality Modeling, San Joaquin Valley PM2.5
Plan for the 2006 PM2.5 NAAQS,'' February 2020 (``EPA's
February 2020 Modeling TSD''). The State considered the EPA's
recommended range of emissions reductions (30 percent to 70 percent)
for the 2013 base year, the projected 2020 attainment year for the 1997
24-hour PM2.5 NAAQS, and the projected 2024 attainment year
for the 2006 PM2.5 NAAQS, and quantified the estimated
response of ambient PM2.5 concentrations to precursor
emissions changes for the first time in a PM2.5 SIP
submission for the San Joaquin Valley. The EPA finds that such
quantification and CARB's consideration of additional information
provide an informed basis on which to make a determination as to
whether ammonia, SOX, and VOC do or do not contribute
significantly to ambient PM2.5 levels that exceed the 1997
24-hour PM2.5 NAAQS in the San Joaquin Valley.\138\
Therefore, we turn to our evaluation of the State's determination for
each of these three precursor pollutants.
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\138\ The State did not evaluate the 2015 Serious area
attainment year. Because the year has passed and the area failed to
attain by the Serious area attainment date, we will evaluate the
precursor analysis for the Serious area plan based on the current
section 189(d) projected attainment date of December 31, 2020.
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a. Ammonia
For ammonia, as detailed above, CARB estimated the ambient
PM2.5 response to both a 30 percent and a 70 percent
emissions reduction. We find that it was appropriate for the State to
consider additional information to interpret those results to determine
whether the ammonia contribution is significant. The primary conclusion
demonstrated by the State's analysis of additional information is that
ammonium nitrate formation is NOX-limited. As discussed in
more detail below, we agree with this conclusion. We have evaluated
CARB's determination that a projected future year is more
representative of conditions in the San Joaquin Valley for sensitivity-
based analyses and that 30 percent is a reasonable upper bound for
ammonia emissions reductions to assess the precursor contribution, as
discussed below.
The State provided ample information from scientific studies based
on ambient measurements to help assess the estimated sensitivity of
ambient PM2.5 to ammonia reductions. Conclusions based on
ambient data are particularly relevant because they provide direct
evidence of the chemical state of the atmosphere and are not dependent
on modeled estimates of emissions or modeled ambient PM2.5
concentrations. Measurements represent the ``real world'' result of the
pollutants' differing geographic distributions, the various
meteorological and chemical factors influencing their conversion to
particulate, and their removal from the atmosphere by deposition and
other processes. The observed abundance of ammonia relative to nitric
acid, and the positive amount of chemically excess ammonia, both
provide strong evidence that ammonia is not the limiting pollutant for
particulate ammonium nitrate formation. They also support the State's
conclusion that PM2.5 concentrations are insensitive to
ammonia emissions reductions.
The relative amount of ammonia and NOX emissions is one
of the most critical factors in determining the sensitivity of ambient
PM2.5 to ammonia reductions. We note that the model response
to precursor reductions may be unrealistically large due to the
underestimation of ammonia emissions and therefore of the ratio of
ammonia to NOX emissions. There is evidence that ammonia
emissions may be underestimated based on direct measurements of ammonia
emissions flux during two measurement campaigns, as discussed in the
EPA's February 2020 Precursor TSD. If ammonia emissions were higher in
the modeling, then ammonia would be more abundant relative to nitrate
and particulate nitrate formation would be more NOX-limited
and less sensitive to ammonia reductions. This would make the model
response more consistent with the ambient measurement studies, which
suggest a very low sensitivity to ammonia. This evidence indicates that
ammonia contribution to PM2.5 levels above the standard is
likely to be less than estimated by the State's modeling in each of the
three years. In comparison to the 2013 and 2020 modeling, the modeling
for the year 2024 incorporates lower NOX emissions and so
has a larger abundance of ammonia relative to nitrate, more similar to
the studies' ambient measurements. Thus, the 2024 response to ammonia
reductions is likely to be more reliable than the 2013 and 2020
responses and appears to be more representative of current atmospheric
conditions despite the use of emissions projections for a future year.
The relative sizes of the ammonia and NOX precursor
emissions inventories after accounting for their differing molecular
weights are a rough indicator of which pollutant is the limiting
pollutant for production of ammonium nitrate because ammonium nitrate
forms from a one-to-one ratio of molecules derived from each precursor
(i.e., one ammonium nitrate forms from one
[[Page 53164]]
ammonium and one nitrate). However, unlike measurements and
photochemical modeling, a simple emissions ratio does not account for
various processes mentioned above; it assumes all the emitted molecules
find one another and react. The State found ammonia to be roughly three
times as abundant as NOX in 2013 after accounting for their
differing molecular weights, and even more abundant in future years.
The EPA repeated the exercise to account for SOX and found
that the ratio of total ammonia to the ammonia needed to react with
both nitrate and sulfate ranged from 2.7 in 2013 to 5.6 in 2028. These
results are approximately the same as the CARB NOX-only
results because SOX emissions are very small relative to
NOX and ammonia emissions (e.g., in 2013, winter daily
emissions were 8.4 tpd of SOX versus 300.5 tpd of
NOX and 309.8 tpd of ammonia).\139\ These observations
support the State's finding that PM2.5 is expected to be
relatively insensitive to ammonia reductions, though they are not
definitive on their own.
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\139\ 2018 PM2.5 Plan, Appendix B, tables B-2, B-3,
and B-4.
---------------------------------------------------------------------------
The State also points to large decreases or projected decreases in
NOX emissions in the San Joaquin Valley from 2013 to 2024,
including a 36 percent reduction from baseline measures by 2020, and a
53 percent reduction by 2024, while CARB projects that ammonia
emissions will remain roughly constant (i.e., decreasing 1-2 percent).
In conjunction with the ambient evidence that ammonia is already
chemically overabundant relative to NOX in the San Joaquin
Valley, this indicates that the overabundance will become even greater
in the future, and thus ambient PM2.5 is expected to be even
less responsive to ammonia reductions. This adds conservatism to the
State's conclusions about ammonia sensitivity based on the scientific
studies.
While the base year for an attainment plan for a given
nonattainment area is generally more representative of current
conditions, there can be situations in which is it more appropriate to
use future conditions representative of when sources will operate, and
the EPA believes that states may use either a base year or a future
year for modeling an ambient PM2.5 response to precursor
emissions reductions, provided the state explains how the choice of
analysis year and associated assumptions are appropriate.\140\ The 2013
modeled responses cannot be considered current at the present time, in
comparison to the 2020 results. Large NOX emissions
reductions have occurred from 2013-2020 and are projected to continue
to occur on through 2024, continuing to decrease the ratio of
NOX to ammonia. In light of this ongoing trend, and the
ambient data indicating that models underestimate ammonia, the EPA
believes that future year results, which more accurately reflect the
expected NOX to ammonia ratio, will continue to be
representative, unlike the 2013 base year. These reductions are the
result of regulations put in place by past air quality planning
decisions and they will occur regardless of the actions that are being
proposed herein. In assessing the effect of potential ammonia
reductions, the EPA believes it is reasonable to account for these
NOX reductions. In addition, as noted above, the greater
abundance of ammonia relative to NOX in the 2024 year
modeling is more consistent with recent ambient measurements, which
suggest that the 2024 responses are more representative of current
atmospheric conditions than the other model years for assessing
sensitivity to ammonia reductions. Therefore, in consideration of the
scientific studies and emissions trends, including the projected large
amount of NOX emissions reductions through the attainment
period, the EPA agrees that use of a future year is appropriate. Given
the available research and ambient data, we conclude that the modeled
2024 year is the most representative of conditions in the San Joaquin
Valley.
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\140\ PM2.5 Precursor Guidance, 35-36.
---------------------------------------------------------------------------
Even if we were to set aside the more representative 2024 modeling,
in the 2020 modeled responses, only the Bakersfield-Planz site is above
the contribution threshold, at 1.9 [micro]g/m\3\. A single value above
the threshold is not determinative, particularly in light of the
additional information provided above, indicating that the modeled
values overestimate the contribution of ammonia to ambient
PM2.5 levels, and that the trend continues toward less
contribution in the future as the ratio of NOX to ammonia
continues to drop. Moreover, the monitored 2020 design value is
attaining the 1997 24-hour PM2.5 NAAQS because, as discussed
above and in section V of this proposal, at the current time there are
not PM2.5 levels above the NAAQS. This is further evidence
that the single 2020 modeled response above the contribution threshold
is not a significant contribution to PM2.5 levels in excess
of the NAAQS, even if the 2020 modeling were considered representative.
In the context of interpreting the full set of modeling results for
ammonia emissions reductions, the EPA also considered the State's
conclusion that the absence of available ammonia controls for sources
in the San Joaquin Valley supports its decision to treat a 30 percent
reduction as a reasonable upper bound on the ammonia emissions
reductions to model in estimating the precursor contribution. As the
State correctly notes, the 30 percent to 70 percent range recommended
by the EPA is based on historical NOX and SOX
emissions reductions, and changes in ammonia emissions levels
nationally from 2011 to 2017 ranged from a 9 percent decrease to a 6
percent increase.\141\ The State's descriptions of past research relied
upon to develop existing rules that apply to ammonia emissions sources,
as well as ongoing research, show that it has considered the
availability of ammonia controls both in the past and present context,
and that the State has a basis for its conclusion that 30 percent is a
reasonable upper bound on achievable reductions for ammonia.
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\141\ Id. at 30, Table 2.
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In sum, we find that the State quantified the sensitivity of
ambient PM2.5 levels to reductions in ammonia using
appropriate modeling techniques that performed well, and that the
State's analysis and use of future year sensitivity data, both 2020 and
2024, is well-supported. We also find that the State adequately
documented its basis for using a 30 percent reduction in ammonia
emissions as an upper bound in the modeling to assess ambient
sensitivity to ammonia emissions reductions. Based on these
considerations, the EPA proposes to approve the State's demonstration
that ammonia emissions do not contribute significantly to ambient
PM2.5 levels that exceed the 1997 24-hour PM2.5
NAAQS in the San Joaquin Valley.
b. SOX
For SOX, the State found that the ambient
PM2.5 responses to SOX emissions reductions were
below the EPA's recommended contribution threshold of 1.3 [micro]g/m\3\
in the Draft PM2.5 Precursor Guidance (and below the EPA
recommended threshold of 1.5 [micro]g/m\3\ in the final
PM2.5 Precursor Guidance), and that for most sites there
would be an increase in ambient PM2.5 levels in response to
SOX reductions (i.e., a disbenefit). The EPA has evaluated
the State's analysis of this disbenefit and resulting conclusion
regarding significance.
Because the results of the sensitivity analysis were all below the
EPA's recommended 24-hour contribution thresholds at both the 30
percent and 70
[[Page 53165]]
percent emissions reductions, and in both the 2013 base year and 2020
(and 2024) future year, it is not necessary to distinguish between the
timing and scale of emissions reductions with respect to the response
of ambient PM2.5 levels as in the ammonia evaluation where
the results diverged according to scale and timing of modeled emissions
reductions. The EPA's February 2020 Precursor TSD contains additional
detail on the EPA's evaluation of SOX as a PM2.5
precursor, including the disbenefit associated with a reduction in
SOX emissions. Accordingly, we find that the State's
decision to rely on the 2013 sensitivity modeling results for a 30
percent SOX reduction is acceptable.
Therefore, on the basis of the modeled ambient PM2.5
response to both a 30 percent and 70 percent reduction in
SOX emissions in 2013, and on the facts and circumstances of
the area, the EPA proposes to approve the State's demonstration that
SOX emissions do not contribute significantly to ambient
PM2.5 levels that exceed the 1997 24-hour PM2.5
NAAQS in the San Joaquin Valley.
c. VOC
For VOC, the State found that the ambient PM2.5 response
to VOC emissions reductions were generally below the EPA's recommended
contribution threshold of 1.3 [micro]g/m\3\ in the Draft
PM2.5 Precursor Guidance and below the EPA's recommended
threshold of 1.5 [micro]g/m\3\ in the final PM2.5 Precursor
Guidance, and often predicted an increase in ambient PM2.5
levels in response to such reductions (i.e., a disbenefit), except for
a 70 percent emissions reduction for the 2013 base year, where the
State predicted the ambient PM2.5 response to be above both
recommended thresholds at a majority of sites. The EPA has evaluated
and agrees with the State's determination that the modeling for future
years is more representative of conditions in the San Joaquin Valley
than the 2013 modeling for sensitivity-based analyses and the State's
resulting conclusion as to whether the contribution from VOC emissions
is significant.
Regarding emissions trends, the EPA agrees that the 8.6 percent
decrease in VOC emissions from 2013 to 2020 and the 9.2 percent
projected decrease from 2013 to 2024 favors reliance on the future year
modeling results. Furthermore, there is a large decrease in
NOX emissions over this period, as discussed in the EPA's
evaluation of ammonia, which affects the atmospheric chemistry with
respect to ambient PM2.5 formation from VOC emissions. The 9
percent VOC emissions reductions and the NOX emissions
reductions are projected to result from implementation of existing
baseline measures. We therefore find it reasonable to rely on future
year 2020 or 2024 modeled responses to VOC emissions reductions, and
both years show a disbenefit from VOC emissions reductions. The EPA
also finds that the State provided a reasonable explanation for the VOC
reduction disbenefit and evidence that it occurs in the San Joaquin
Valley.
For these reasons, we propose to approve the State's demonstration
that VOC emissions do not contribute significantly to ambient
PM2.5 levels that exceed the 1997 24-hour PM2.5
NAAQS in the San Joaquin Valley.
C. Attainment Plan Control Strategy
1. Statutory and Regulatory Requirements
Section 189(b)(1)(B) of the Act requires for any Serious
PM2.5 nonattainment area that the state submit provisions to
assure that BACM for the control of PM2.5 and
PM2.5 precursors shall be implemented no later than four
years after the date the area is reclassified as a Serious area. The
EPA has defined BACM in the PM2.5 SIP Requirements Rule to
mean ``any technologically and economically feasible control measure
that . . . can achieve greater permanent and enforceable emissions
reductions of direct PM2.5 emissions and/or emissions of
PM2.5 plan precursors from sources in the area than can be
achieved through the implementation of RACM on the same source(s). BACM
includes best available control technology (BACT).'' \142\
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\142\ 40 CFR 51.1000 (definitions). In longstanding guidance,
the EPA has similarly defined BACM to mean, ``among other things,
the maximum degree of emissions reduction achievable for a source or
source category, which is determined on a case-by-case basis
considering energy, environmental, and economic impacts.'' General
Preamble Addendum, 42010, 42013.
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Because the 2015 Serious area attainment date has passed, and the
EPA found that the area failed to attain by the Serious area attainment
date, we are evaluating the submission for compliance with the BACM/
BACT requirements now, in conjunction with the State's SIP submission
intended to meet both the Serious area plan and section 189(d) plan
requirements.
The EPA generally considers BACM a control level that goes beyond
existing RACM-level controls, for example by expanding the use of RACM
controls or by requiring preventative measures instead of
remediation.\143\ Indeed, as implementation of BACM and BACT is
required when a Moderate nonattainment area is reclassified as Serious
due to its inability to attain the NAAQS through implementation of
``reasonable'' measures, it is logical that ``best'' control measures
should represent a more stringent and potentially more costly level of
control.\144\ If RACM and RACT level controls of emissions have been
insufficient to reach attainment, the CAA contemplates the
implementation of more stringent controls, controls on more sources, or
other adjustments to the control strategy are necessary to attain the
NAAQS in the area.
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\143\ 81 FR 58010, 58081 and General Preamble Addendum, 42011,
42013.
\144\ Id. and General Preamble Addendum, 42009-42010.
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Under the PM2.5 SIP Requirements Rule, those control
measures that otherwise meet the definition of BACM/BACT but ``can only
be implemented in whole or in part beginning four years after
reclassification'' are referred to as ``additional feasible measures.''
\145\ In accordance with the requirements of CAA section 172(c)(6), a
Serious area plan must include any additional feasible measures to
control emissions of direct PM2.5 and PM2.5
precursors that are necessary and appropriate to provide for attainment
of the relevant NAAQS as expeditiously as practicable and no later than
the applicable attainment date.\146\
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\145\ 40 CFR 51.1000, 40 CFR 51.1010(a)(4)(ii).
\146\ Because the Serious area attainment year has passed and
the area failed to attain by the Serious area attainment date, we
will evaluate the BACM/BACT and additional feasible measure analysis
for the Serious area plan with respect to the current section 189(d)
projected attainment date of December 31, 2020.
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Consistent with longstanding guidance provided in the General
Preamble Addendum, the preamble to the PM2.5 SIP
Requirements Rule discusses the following steps for determining BACM
and BACT and additional feasible measures:
(1) Develop a comprehensive emissions inventory of the sources of
PM2.5 and PM2.5 precursors;
(2) Identify potential control measures;
(3) Determine whether an available control measure or technology is
technologically feasible;
(4) Determine whether an available control measure or technology is
economically feasible; and
(5) Determine the earliest date by which a control measure or
technology can be implemented in whole or in part.\147\
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\147\ 81 FR 58010, 58083-58085.
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The EPA allows consideration of factors such as physical plant
layout,
[[Page 53166]]
energy requirements, needed infrastructure, and workforce type and
habits when considering technological feasibility. For purposes of
evaluating economic feasibility, the EPA allows consideration of
factors such as the capital costs, operating and maintenance costs, and
cost effectiveness (i.e., cost per ton of pollutant reduced by a
measure or technology) associated with the measure or control.\148\
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\148\ 40 CFR 51.1010(a)(3) and 81 FR 58010, 58041-58042.
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Once these analyses are complete, the state must use this
information to develop enforceable control measures and submit them to
the EPA for evaluation as SIP revisions to meet the basic requirements
of CAA section 110 and any other applicable substantive provisions of
the Act. The EPA is using these steps as guidelines in the evaluation
of the BACM and BACT measures and related analyses in the SJV
PM2.5 Plan. Furthermore, because the EPA has not previously
taken action to approve the California SIP as meeting the subpart 4
Moderate area planning requirements under CAA section 189 for the 1997
24-hour PM2.5 NAAQS for the San Joaquin Valley area, the EPA
is reviewing the SJV PM2.5 Plan for compliance with those
requirements.\149\
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\149\ The EPA does not normally conduct a separate evaluation to
determine whether a Serious area plan's measures also meet the RACM
requirements. As explained in the General Preamble Addendum, we
interpret the BACM requirement as generally subsuming the RACM
requirement--i.e., if we determine that the measures are indeed the
``best available,'' we have necessarily concluded that they are
``reasonably available.'' (General Preamble Addendum, 42010).
Therefore, a separate analysis to determine if the measures
represent a RACM level of control is not necessary. A proposed
approval of a Plan's provisions concerning implementation of BACM is
also a proposed finding that the Plan provides for the
implementation of RACM.
---------------------------------------------------------------------------
The overarching requirement for the CAA section 189(d) attainment
control strategy is that it provides for attainment of the NAAQS as
expeditiously as practicable.\150\ The control strategy must include
any additional measures (beyond those already adopted in previous
nonattainment plans for the area as RACM/RACT or BACM/BACT) that are
needed for the area to attain expeditiously. This includes reassessing
any measures previously rejected during the development of any Moderate
area or Serious area attainment plan control strategy.\151\ The state
must also demonstrate that it will, at a minimum, achieve an annual
five percent reduction in emissions of direct PM2.5 or any
PM2.5 plan precursor from sources in the area, based on the
most recent emissions inventory for the area.\152\
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\150\ 81 FR 58010, 58100.
\151\ 40 CFR 50.1010(c)(2)(ii).
\152\ CAA section 189(d) and 40 CFR 51.1010(c).
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In the PM2.5 SIP Requirements Rule, the EPA clarified
its interpretation of the statutory language in CAA section 189(d)
requiring a state to submit a new attainment plan to achieve annual
reductions ``from the date of such submission until attainment,'' to
mean annual reductions beginning from the due date of such submission
until the new projected attainment date for the area based on the new
or additional control measures identified to achieve at least five
percent emissions reductions annually.\153\ This interpretation is
intended to make clear that even if a state is late in submitting its
CAA section 189(d) plan, the area must still achieve its annual five
percent emissions reductions beginning from the date by which the state
was required to make its CAA section 189(d) submission, not by some
later date. Because the deadline for California to submit a section
189(d) plan for the 1997 PM2.5 NAAQS in the San Joaquin
Valley was December 31, 2016, one year after the December 31, 2015
attainment date for these NAAQS under CAA section 188(c)(2), the
starting point for the five percent emissions reduction requirement
under section 189(d) for this area is 2017.
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\153\ 81 FR 58010, 58101.
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2. Summary of the State's Submission and the EPA's Evaluation and
Proposed Action
a. Control Strategy
For the Serious area and section 189(d) plan requirements for the
1997 24-hour PM2.5 NAAQS the State based the control
strategy in the SJV PM2.5 Plan on ongoing emissions
reductions from baseline control measures.\154\ As we use the term
here, baseline measures are State and District regulations adopted
prior to the development of the SJV PM2.5 Plan that continue
to achieve emissions reductions through the projected 2020 attainment
year for the 1997 24-hour PM2.5 NAAQS and beyond. The State
describes the baseline measures in the 2018 PM2.5 Plan in
Chapter 4,\155\ Appendix C (``Stationary Source Control Measure
Analyses''), and Appendix D (``Mobile Source Control Measure
Analyses''). The State incorporates reductions generated by these
baseline measures into the projected baseline inventories and
reductions resulting from District measures are individually quantified
in Appendix C.
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\154\ Because the 2015 Serious area attainment date has passed,
and the EPA found that the area failed to attain by the Serious area
attainment date, we are evaluating the control strategy for the
Serious area requirements based on the timeline associated with the
current section 189(d) projected attainment date of December 31,
2020.
\155\ 2018 PM2.5 Plan, Chapter 4, Table 4-2.
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In the 2018 PM2.5 Plan, CARB indicates that mobile
sources emit over 85 percent of the NOX emissions in the San
Joaquin Valley and that CARB has adopted and amended regulations to
reduce public exposure to diesel particulate matter, which includes
direct PM2.5 and NOX, from ``fuel sources,
freight transport sources like heavy-duty diesel trucks, transportation
sources like passenger cars and buses, and non-road sources like large
construction equipment.'' \156\
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\156\ 2018 PM2.5 Plan, Chapter 4, 4-9. For CARB's
BACM analysis for mobile source measures, see 2018 PM2.5
Plan, Appendix D, including analyses for on-road light-duty vehicles
and fuels (starting on page D-17), on-road heavy-duty vehicles and
fuels (starting on page D-35), and non-road sources (starting on
page D-64).
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Given the need for substantial emissions reductions from mobile and
area sources to meet the NAAQS in California nonattainment areas, the
State of California has developed stringent control measures for on-
road and non-road mobile sources and the fuels that power them.
California has unique authority under CAA section 209 (subject to a
waiver or authorization as applicable by the EPA) to adopt and
implement new emissions standards for many categories of on-road
vehicles and engines and new and in-use non-road vehicles and engines.
The EPA has approved many such mobile source regulations for which it
has issued waiver authorizations as revisions to the California
SIP.\157\
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\157\ For example, see 81 FR 39424 (June 16, 2016); 82 FR 14446
(March 21, 2017); and 83 FR 23232 (May 18, 2018).
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CARB's mobile source program extends beyond regulations that are
subject to the waiver or authorization process set forth in CAA section
209 to include standards and other requirements to control emissions
from in-use heavy-duty trucks and buses, gasoline and diesel fuel
specifications, and many other types of mobile sources. Generally,
these regulations have also been submitted and approved as revisions to
the California SIP.\158\
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\158\ For example, see the EPA's approval of standards and other
requirements to control emissions from in-use heavy-duty diesel
trucks (77 FR 20308, April 4, 2012), revisions to the California on-
road reformulated gasoline and diesel fuel regulations (75 FR 26653,
May 12, 2010), and revisions to the California motor vehicle
inspection and maintenance program (75 FR 38023, July 1, 2010).
---------------------------------------------------------------------------
As to stationary and area sources, the SJV PM2.5 Plan
indicates that regulations adopted for prior attainment plans
[[Page 53167]]
continue to reduce emissions of NOX and direct
PM2.5.\159\ Specifically, Table 4-1 of the 2018
PM2.5 Plan identifies 33 District measures that limit
NOX and direct PM2.5 emissions.\160\ The EPA has
approved each of the identified measures into the California SIP,\161\
with two exceptions.
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\159\ 2018 PM2.5 Plan, Chapter 4, 4-3. For the
District's BACM analysis of stationary and area source measures, see
2018 PM2.5 Plan, Appendix C.
\160\ 2018 PM2.5 Plan, Chapter 4, Table 4-1.
\161\ See EPA Region IX's website for information on District
control measures that have been approved into the California SIP,
available at: https://www.epa.gov/sips-ca/epa-approved-san-joaquin-valley-unified-air-district-regulations-california-sip.
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First, the District amended Rule 4905 (``Natural Gas-fired, Fan-
type, Residential Central Furnaces'') on October 15, 2020, to extend
the period during which manufacturers may pay emissions fees in lieu of
meeting the rule's NOX emissions limits.\162\ CARB submitted
the amended rule to the EPA on December 30, 2020,\163\ and the EPA has
not yet proposed any action on this submission. The EPA approved a
prior version of Rule 4905 into the California SIP on March 29,
2016.\164\ As part of that rulemaking, the EPA noted that because of
the option in Rule 4905 to pay mitigation fees in lieu of compliance
with emissions limits, emissions reductions associated with the rule's
emissions limits would not be creditable in any attainment plan without
additional documentation.\165\ Until the District submits the necessary
documentation to credit emissions reductions achieved by Rule 4905
toward an attainment control strategy, this rule is not creditable for
SIP purposes. The Plan indicates that the District attributed 0.06 tpd
of NOX reductions between 2013 and 2020 to Rule 4905.\166\
These emissions reductions have de minimis impacts on the attainment
demonstration for the 1997 24-hour PM2.5 NAAQS in the SJV
PM2.5 Plan.
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\162\ SJVUAPCD, Final Draft Staff Report with Appendix for
Proposed Amendments to Rule 4905, ``Adopt Proposed Amendments to
Rule 4905 (Natural Gas-fired, Fan-type Central Furnaces),'' 2.
\163\ Letter dated December 28, 2020, from Richard W. Corey,
Executive Officer, CARB, to John Busterud, Regional Administrator,
EPA Region 9. CARB's submittal letter formally withdrew a previously
amended version of Rule 4905 adopted by the District on June 21,
2018 and submitted to the EPA by CARB on November 21, 2018.
\164\ 81 FR 17390 (March 29, 2016) (approving Rule 4905 as
amended January 22, 2015).
\165\ EPA, Region IX Air Division, ``Technical Support Document
for EPA's Proposed Rulemaking for the California State
Implementation Plan (SIP), San Joaquin Valley Unified Air Pollution
Control District's Rule 4905, Natural Gas-Fired, Fan-Type Central
Furnaces,'' October 5, 2015, n. 8.
\166\ 2018 PM2.5 Plan, Appendix C, C-290.
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Second, the 2018 PM2.5 Plan lists Rule 4203
(``Particulate Matter Emissions from Incineration of Combustible
Refuse'') as a baseline measure. This rule has not been approved into
the California SIP.\167\ Appendix C of the 2018 PM2.5 Plan
indicates, however, that the emissions inventory for incineration of
combustible refuse is 0.00 tpd of NOX and 0.00 direct
PM2.5 from 2013 through 2020.\168\ Thus, although the
District included this rule as a baseline measure, there are no
meaningful reductions associated with this rule that would affect the
attainment demonstration in the SJV PM2.5 Plan.
---------------------------------------------------------------------------
\167\ The EPA does not have any pending SIP submission for Rule
4203.
\168\ 2018 PM2.5 Plan, Appendix C, C-46.
---------------------------------------------------------------------------
In sum, although Table 4-1 of the 2018 PM2.5 Plan
identifies two baseline measures that are not creditable for SIP
purposes at this time, we find that the total emissions reductions
attributed to these measures in the future baseline inventories have de
minimis effects on the attainment demonstration in the Plan.
b. Best Available Control Measures
We are evaluating the State's BACM demonstration for the 1997 24-
hour PM2.5 NAAQS against the section 189(b)(1)(B) Serious
area plan BACM requirement, and the section 189(d) plan requirement to
address all Serious area plan requirements that the State has not
already met. Because we have already found that the State failed to
attain the 1997 24-hour PM2.5 NAAQS in the San Joaquin
Valley area by the Serious area attainment date, and because we have
not previously found that the state has met the BACM requirement for
purposes of the 1997 24-hour PM2.5 NAAQS, we are evaluating
the State's submission against the Serious area BACM requirement in
light of the section 189(d) control plan timeline. The State's BACM
demonstration is presented in Appendix C (``Stationary Source
Controls'') and Appendix D (``Mobile Source Control Measure Analyses'')
of the 2018 PM2.5 Plan.\169\ As discussed in section IV.A of
this proposed rule, Appendix B (``Emissions Inventory'') of the 2018
PM2.5 Plan contains the planning inventories for direct
PM2.5 and all PM2.5 precursors (NOX,
SOX, VOC, and ammonia) for the San Joaquin Valley
nonattainment area together with documentation to support these
inventories. Each inventory includes emissions from stationary, area,
on-road, and non-road emissions sources, and the State specifically
identifies the condensable component of direct PM2.5 for
relevant stationary source and area source categories. As discussed in
section IV.B of this proposed rule, the State concludes that the Plan
should control emissions of PM2.5 and NOX to
reach attainment. Accordingly, the BACM and BACT evaluation in the Plan
addresses potential controls for sources of those pollutants.
---------------------------------------------------------------------------
\169\ Appendices C and D also present an MSM analysis for the
purposes of meeting a precondition for an extension of the Serious
area attainment date under CAA section 188(e) for the 2006
PM2.5 NAAQS. The San Joaquin Valley area is not subject
to the MSM requirement for the 1997 24-hour PM2.5 NAAQS.
Thus, the EPA is evaluating the Plan's control strategy for
implementation of BACM and BACT only.
---------------------------------------------------------------------------
For stationary and area sources, the District identifies the
sources of direct PM2.5 and NOX in the San
Joaquin Valley that are subject to District emissions control measures
and provides its evaluation of these regulations for compliance with
BACM requirements in Appendix C of the 2018 PM2.5 Plan. As
part of its process for identifying candidate BACM and considering the
technical and economic feasibility of additional control measures, the
District reviewed the EPA's guidance documents on BACM, additional
guidance documents on control measures for direct PM2.5 and
NOX emissions sources, and control measures implemented in
other ozone and PM2.5 nonattainment areas in California and
other states.\170\ The District also provides an analysis of several
SIP-approved VOC regulations that, according to the District, also
provide ammonia co-benefits.\171\ Based on these analyses, the District
concludes that all best available control measures for stationary and
area sources are in place in the San Joaquin Valley for NOX
and directly emitted PM2.5 for purposes of meeting the BACM/
BACT requirement for the 1997 24-hour PM2.5 NAAQS. We
provide an evaluation of many of the District's control measures for
stationary sources and area sources in section III of the EPA's 1997
24-hour PM2.5 TSD together with recommendations for possible
future improvements to these rules.
---------------------------------------------------------------------------
\170\ 2018 PM2.5 Plan, Chapter 4, section 4.3.1.
\171\ 2018 PM2.5 Plan, Appendix C., section C.25.
---------------------------------------------------------------------------
For mobile sources, CARB identifies the sources of direct
PM2.5 and NOX in the San Joaquin Valley that are
subject to the State's emissions control measures and provides its
evaluation of these regulations for compliance with BACM requirements
in Appendix D of the 2018 PM2.5 Plan. Appendix D describes
CARB's process for determining BACM, including identification of the
sources of direct PM2.5 and NOX in the San
Joaquin
[[Page 53168]]
Valley, identification of potential control measures for such sources,
assessment of the stringency and feasibility of the potential control
measures, and adoption and implementation of feasible control
measures.\172\
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\172\ 2018 PM2.5 Plan, Appendix D, Chapter II.
---------------------------------------------------------------------------
Mobile source categories for which CARB has primary responsibility
for reducing emissions in California include most new and existing on-
and non-road engines and vehicles and motor vehicle fuels. The SJV
PM2.5 Plan's BACM demonstration provides a general
description of CARB's key mobile source programs and regulations and a
comprehensive table listing on-road and non-road mobile source
regulatory actions taken by CARB since 1985.\173\
---------------------------------------------------------------------------
\173\ Id. at Table 17.
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Appendix D of the 2018 PM2.5 Plan also describes the
current efforts of the eight local jurisdiction metropolitan planning
organizations (MPOs) to implement cost-effective transportation control
measures (TCMs) in the San Joaquin Valley.\174\ TCMs are projects that
reduce air pollutants from transportation sources by reducing vehicle
use, traffic congestion, or vehicle miles traveled. TCMs are currently
being implemented in the San Joaquin Valley as part of the Congestion
Mitigation and Air Quality cost effectiveness policy adopted by the
eight local jurisdiction MPOs and in the development of each Regional
Transportation Plan (RTP). The Congestion Mitigation and Air Quality
policy, which is included in a number of the District's prior
attainment plan submissions for the ozone and PM2.5 NAAQS,
provides a standardized process for distributing 20 percent of the
Congestion Mitigation and Air Quality funds to projects that meet a
minimum cost effectiveness threshold beginning in fiscal year 2011. The
MPOs revisited the minimum cost effectiveness standard during the
development of their 2018 RTPs and 2019 Federal Transportation
Improvement Program and concluded that they were implementing all
reasonable transportation control measures.\175\ Appendix D of the
District's ``2016 Ozone Plan for 2008 8-Hour Ozone Standard,'' adopted
June 16, 2016, contains a listing of adopted TCMs for the San Joaquin
Valley.\176\
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\174\ Id. at D-127 and D-128.
\175\ Id. at D-127.
\176\ Id. and SJVUAPCD, ``2016 Ozone Plan for 2008 8-Hour Ozone
Standard'' (adopted June 16, 2016), Appendix D, Attachment D, tables
D-10 to D-17.
---------------------------------------------------------------------------
We have reviewed the State's and District's analysis and
determination in the SJV PM2.5 Plan that their baseline
mobile, stationary, and area source control measures meet the
requirements for BACM for sources of direct PM2.5 and
applicable PM2.5 plan precursors (i.e., NOX) for
purposes of the 1997 24-hour PM2.5 NAAQS. In our review, we
considered our evaluation of the State's and District's rules in
connection with our approval of the demonstrations for BACM (including
BACT) and MSM for the 2006 PM2.5 NAAQS.\177\ We find that
the evaluation processes followed by CARB and the District in the SJV
PM2.5 Plan to identify potential BACM were generally
consistent with the requirements of the PM2.5 SIP
Requirements Rule, the State's and District's evaluation of potential
measures is appropriate, and the State and District have provided
reasoned justifications for their rejection of potential measures based
on technological or economic infeasibility. We also agree with the
District's conclusion that all reasonable TCMs are being implemented in
the San Joaquin Valley and propose to find that these TCMs implement
BACM for transportation sources.
---------------------------------------------------------------------------
\177\ 85 FR 44192.
---------------------------------------------------------------------------
For the foregoing reasons, we propose to find that the SJV
PM2.5 Plan provides for the implementation of BACM for
sources of direct PM2.5 and NOX as expeditiously
as practicable in accordance with the requirements of CAA section
189(b)(1)(B), and in satisfaction of both the Serious area and section
189(d) plan requirements.
c. Section 189(d) Five Percent Requirement
The SJV PM2.5 Plan's demonstration of annual five
percent reductions in NOX emissions is in section 5.2 of the
2018 PM2.5 Plan. As shown in Table 3, the demonstration uses
the 2013 base year inventory as the starting point from which the five
percent per year emissions reductions are calculated and uses 2017 as
the year from which the reductions start. The target required reduction
in 2017 is five percent of the base year (2013) inventory, which is a
reduction of approximately 15.9 tpd of NOX, and the targets
for subsequent years are additional reductions of five percent per year
until the 2020 attainment year. The projected emissions inventories
reflect NOX emissions reductions achieved by baseline
control measures and the demonstration shows that these NOX
emissions reductions are greater than the required five percent per
year.
Table 3--2017-2020 Annual Five Percent Emissions Reductions Demonstration for the San Joaquin Valley
----------------------------------------------------------------------------------------------------------------
CEPAM
% Reduction 5% Target (tpd inventory
Year from 2013 base NOX) v1.05 (tpd Meets 5%?
year NOX)
----------------------------------------------------------------------------------------------------------------
2013 (base year).................... .............. .............. 317.3 ..........................
2017................................ 5 301.3 233.4 Yes.
2018................................ 10 285.5 221.5 Yes.
2019................................ 15 269.6 214.5 Yes.
2020................................ 20 253.8 203.3 Yes.
----------------------------------------------------------------------------------------------------------------
Source: 2018 PM2.5 Plan, Table 5-2.
The EPA proposes to find that the State's use of 2017 as the
starting point from which the five percent per year emissions
reductions should begin is reasonable and consistent with the CAA. As
discussed in section IV.C.1 of this document, the EPA interprets the
language under CAA section 189(d) to require a state to submit a new
attainment plan to achieve annual reductions ``from the date of such
submission until attainment.'' The 2018 PM2.5 Plan was not
submitted until May 10, 2019. However, the Serious area attainment
deadline for the San Joaquin Valley nonattainment area for the 1997
PM2.5 NAAQS was December 31, 2015.\178\ Accordingly, a plan
submittal
[[Page 53169]]
to meet the requirements under section 189(d) was due by December 31,
2016, and reductions were required to occur as of that date. The
decline in emissions from 2017 to 2020 shows that reductions did, in
fact, occur within the required timeframe. Furthermore, the State's
demonstration shows that NOX emissions reductions from 2017
to 2020 are greater than the required five percent per year. Thus, the
EPA proposes to find that the SJV PM2.5 Plan meets the CAA
189(d) requirement to provide for an annual reduction in
PM2.5 or PM2.5 precursor emissions of not less
than five percent of the amount of such emissions reported in the most
recent inventory prepared for the area.
---------------------------------------------------------------------------
\178\ 80 FR 18528.
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D. Attainment Demonstration and Modeling
1. Statutory and Regulatory Requirements
Section 189(b)(1)(A) of the CAA requires that each Serious area
plan include a demonstration (including air quality modeling) that the
plan provides for attainment of the PM2.5 NAAQS by the
applicable attainment date. As discussed in section IV of this
proposal, given that the outermost statutory Serious area attainment
date for the San Joaquin Valley area (i.e., December 31, 2015) has
passed and that the EPA has already found that the SJV area failed to
attain by that date, the EPA must evaluate the State's plan for
attainment by a later attainment date. Given that the finding of
failure to attain triggered the State's obligation to submit a new plan
meeting the requirements of section 189(d), the EPA is evaluating the
SJV PM2.5 Plan in light of the outermost attainment date
required in section 189(d). That section requires that the attainment
date be as expeditious as practicable, but not later than five years
following the EPA's finding that the area failed to attain the NAAQS by
the applicable Serious area attainment date. In this case, the State
projected such attainment by December 31, 2020, i.e., by the relevant
statutory date.
The PM2.5 SIP Requirements Rule explains that the same
general requirements that apply to Moderate and Serious area plans
under CAA sections 189(a) and 189(b) should apply to plans developed
pursuant to CAA section 189(d)--i.e., the plan must include a
demonstration (including air quality modeling) that the control
strategy provides for attainment of the PM2.5 NAAQS as
expeditiously as practicable.\179\ For purposes of determining the
attainment date that is as expeditious as practicable, the state must
conduct future year modeling that takes into account emissions growth,
known controls (including any controls that were previously determined
to be RACM/RACT or BACM/BACT), the five percent per year emissions
reductions required by CAA section 189(d), and any other emissions
controls that are needed for expeditious attainment of the NAAQS.
---------------------------------------------------------------------------
\179\ 40 CFR 51.1011(b)(1); 81 FR 58010, 58102.
---------------------------------------------------------------------------
The EPA's PM2.5 modeling guidance \180\ (``Modeling
Guidance'' and ``Modeling Guidance Update'') recommends that a
photochemical model, such as the Comprehensive Air Quality Model with
Extensions (CAMx) or Community Multiscale Air Quality Model (CMAQ), be
used to simulate a base case, with meteorological and emissions inputs
reflecting a base case year, to replicate concentrations monitored in
that year. The model application to the base year undergoes a
performance evaluation to ensure that it satisfactorily corroborates
the concentrations monitored in that year. The model may then be used
to simulate emissions occurring in other years required for a plan,
namely the base year (which may differ from the base case year) and
future year.\181\ The modeled response to the emissions changes between
those years is used to calculate relative response factors (RRFs) that
are applied to the design value in the base year to estimate the
projected design value in the future year for comparison against the
NAAQS. Separate RRFs are estimated for each chemical species component
of PM2.5, and for each quarter of the year, to reflect their
differing responses to seasonal meteorological conditions and
emissions. Because each species is handled separately, before applying
an RRF, the base year design value should be speciated using available
chemical species measurements--that is, each day's measured
PM2.5 design value must be split into its species
components. The Modeling Guidance provides additional detail on the
recommended approach.\182\
---------------------------------------------------------------------------
\180\ Memorandum dated November 29, 2018, from Richard Wayland,
Air Quality Assessment Division, Office of Air Quality Planning and
Standards, EPA, to Regional Air Division Directors, EPA, Subject:
``Modeling Guidance for Demonstrating Air Quality Goals for Ozone,
PM2.5, and Regional Haze,'' (``Modeling Guidance''), and
memorandum dated June 28, 2011 from Tyler Fox, Air Quality Modeling
Group, Office of Air Quality Planning and Standards, EPA, to
Regional Air Program Managers, EPA, Subject: ``Update to the 24 Hour
PM2.5 NAAQS Modeled Attainment Test,'' (``Modeling
Guidance Update'').
\181\ In this section, we use the terms ``base case,'' ``base
year'' or ``baseline,'' and ``future year'' as described in section
2.3 of the EPA's Modeling Guidance. The ``base case'' modeling
simulates measured concentrations for a given time period, using
emissions and meteorology for that same year. The modeling ``base
year'' (which can be the same as the base case year) is the
emissions starting point for the plan and for projections to the
future year, both of which are modeled for the attainment
demonstration. Modeling Guidance, 37-38.
\182\ Modeling Guidance, section 4.5, ``What is the Recommended
Modeled Attainment Test for the 24-Hour NAAQS.''
---------------------------------------------------------------------------
2. Summary of the State's Submission
As discussed in section IV.C, the SJV PM2.5 Plan
includes a modeled demonstration projecting that the San Joaquin Valley
would attain the 1997 24-hour PM2.5 NAAQS by December 31,
2020, based on ongoing emissions reductions from baseline control
measures. CARB conducted photochemical modeling with the CMAQ model
using inputs developed from routinely available meteorological and air
quality data, as well as more detailed and extensive data from the
DISCOVER-AQ field study conducted in January and February of 2013.\183\
The Plan's primary discussion of the photochemical modeling appears in
Appendix K (``Modeling Attainment Demonstration'') of the 2018
PM2.5 Plan. The State briefly summarizes the area's air
quality problem in Chapter 2 (``Air Quality Challenges and Trends'')
and the modeling results in Chapter 5.3 (``Attainment Demonstration and
Modeling'') of the 2018 PM2.5 Plan. The State provides a
conceptual model of PM2.5 formation in the San Joaquin
Valley as part of the modeling protocol in Appendix L (``Modeling
Protocol''). Appendix J (``Modeling Emission Inventory'') describes
emissions input preparation procedures. The State presents additional
relevant information in Appendix C (``Weight of Evidence Analysis'') of
the CARB Staff Report, which includes ambient trends and other data in
support of the attainment demonstration.
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\183\ NASA, ``Deriving Information on Surface conditions from
COlumn and VERtically Resolved Observations Relevant to Air
Quality,'' available at https://www.nasa.gov/mission_pages/discover-aq/.
---------------------------------------------------------------------------
CARB's air quality modeling approach investigated the many inter-
connected facets of modeling ambient PM2.5 in the San
Joaquin Valley, including model input preparation, model performance
evaluation, use of the model output for the numerical NAAQS attainment
test, and modeling documentation. Specifically, this required the
development and evaluation of a conceptual model, modeling protocol,
episode (i.e., base year) selection, modeling domain, CMAQ model
selection, initial and boundary condition procedures, meteorological
[[Page 53170]]
model choice and performance, modeling emissions inventory preparation
procedures, model performance, attainment test procedure, adjustments
to baseline air quality for modeling, the 2020 attainment test, and an
unmonitored area analysis. CARB's supplemental weight of evidence
analysis further supports the Plan's demonstration of attainment by the
end of 2020. These analyses are generally consistent with the EPA's
recommendations in the Modeling Guidance.
The model performance evaluation in Appendix K includes statistical
and graphical measures of model performance. The magnitude and timing
of predicted concentrations of total PM2.5, as well as of
its ammonium and nitrate components, generally match the occurrence of
elevated PM2.5 levels in the measured observations. A
comparison to other recent modeling efforts shows good model
performance on bias, error, and correlation with measurements, for
total PM2.5 and for most of its chemical components. The
Weight of Evidence Analysis shows the downward trend in NOX
emissions along with a 70 percent decrease between 1999 and 2017 in the
number of days above the 1997 24-hour PM2.5 NAAQS.\184\ The
analysis also shows decreases in daily PM2.5 concentrations
during winter, and in the frequency of high PM2.5
concentrations generally.\185\ Available ambient air quality data show
that total PM2.5 and ammonium nitrate concentrations have
declined over the 2004-2017 period, despite some increases from time to
time.\186\ These trends show that there has been an improvement in air
quality due to emissions reductions in the San Joaquin Valley, although
that point is not fully reflected in the 98th percentile statistic,
which is the basis for the regulatory design value.
---------------------------------------------------------------------------
\184\ Weight of Evidence Analysis, 27-28, Figure 14, and Figure
24.
\185\ Id. at Figure 16 and Figure 17.
\186\ Id. at Figure 21.
---------------------------------------------------------------------------
The State conducted three CMAQ \187\ simulations: (1) A 2013 base
year simulation to demonstrate that the model reasonably reproduced the
observed PM2.5 concentrations in the San Joaquin Valley; (2)
a 2013 baseline year simulation that was the same as the 2013 base year
simulation but excluded exceptional event emissions, such as wildfire
emissions; and (3) a 2020 future year simulation that reflects
projected emissions growth and reductions due to controls that have
already been adopted and implemented.\188\
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\187\ CMAQ Version 5.0.2.
\188\ 2018 PM2.5 Plan, 5-5.
---------------------------------------------------------------------------
Table 4 shows the 2013 base year and 2020 projected future year 24-
hour PM2.5 design values at monitoring sites in the San
Joaquin Valley. As recommended by the EPA's guidance, the 2013 base
year design value for modeling purposes is a weighted average of three
monitored design values, to minimize the influence of year-to-year
variability. The highest 2020 projected design value is 47.6 [micro]g/
m\3\ at the Bakersfield-California monitoring site, which is below the
65 [micro]g/m\3\ level of the 1997 24-hour PM2.5 NAAQS.
Table 4--Projected Future 24-Hour PM2.5 Design Values at Monitoring
Sites in the San Joaquin Valley ([micro]g/m \3\)
------------------------------------------------------------------------
2013 Base 2020 Projected
Monitoring site design value design value
------------------------------------------------------------------------
Bakersfield--California................. 64.1 47.6
Fresno-Garland.......................... 60.0 44.3
Hanford................................. 60.0 43.7
Fresno-Hamilton & Winery................ 59.3 45.6
Clovis.................................. 55.8 41.1
Visalia................................. 55.5 42.8
Bakersfield-Planz....................... 55.5 41.2
Madera.................................. 51.0 38.9
Turlock................................. 50.7 37.8
Modesto................................. 47.9 35.8
Merced-M. Street........................ 46.9 32.9
Stockton................................ 42.0 33.5
Merced-S Coffee......................... 41.1 30.0
Manteca................................. 36.9 30.1
Tranquility............................. 29.5 21.5
------------------------------------------------------------------------
Source: 2018 PM2.5 Plan, Table 5-5.
3. The EPA's Review of the State's Submission
The EPA must make several findings in order to approve the modeled
attainment demonstration in an attainment plan SIP submission. First,
we must find that the attainment demonstration's technical bases,
including the emissions inventories and air quality modeling, are
adequate. As discussed in section IV.A of this preamble, we are
proposing to approve the emissions inventories on which the SJV
PM2.5 Plan's attainment demonstration and related provisions
are based. Furthermore, the EPA has evaluated the State's choice of
model and the extensive discussion in the Modeling Protocol about
modeling procedures, tests, and performance analyses. We find that the
analyses are consistent with the EPA's guidance on modeling for
PM2.5 attainment planning purposes. Based on these reviews,
we find that the modeling in the Plan is adequate for the purposes of
supporting the RFP demonstration and demonstration of attainment by
2020 and are proposing to approve the air quality modeling. For further
detail, see the EPA's February 2020 Modeling TSD.
Second, we must find that the SIP submittal provides for
expeditious attainment through the timely implementation of the control
strategy. As discussed in section IV.C of this preamble, we are
proposing to approve the control strategy in the SJV PM2.5
Plan, including the BACM/BACT demonstration and the five percent
emissions reduction requirement under CAA sections 189(b)(1)(B) and
189(d), respectively.
[[Page 53171]]
Third, the EPA must find that the emissions reductions that are
relied on for attainment in the SIP submission are creditable. As
discussed in section IV.C.2.a, the SJV PM2.5 Plan relies
principally on rules that have already been adopted and approved by the
EPA to achieve the emissions reductions needed to attain the 1997 24-
hour PM2.5 NAAQS in the San Joaquin Valley. We present our
evaluation of the rules in section IV.C.2.a and in sections II and III
of the EPA's 1997 24-hour PM2.5 TSD. We find that all but
two of these rules are SIP-creditable and that the total emissions
reductions attributed to the two measures that are not SIP-creditable
have de minimis impacts on the attainment demonstration in the Plan.
The EPA has also reviewed ambient monitoring data recorded at air
quality monitors throughout the San Joaquin Valley PM2.5
nonattainment area during the three years leading up to the projected
December 31, 2020 attainment date (i.e., 2018-2020). As discussed in
section V of this proposal, based on these data, we are proposing to
find that the San Joaquin Valley area attained the 1997 24-hour
PM2.5 NAAQS by the December 31, 2020 attainment date.
Based on these evaluations, we propose to determine that the SJV
PM2.5 Plan provides for attainment of the 1997 24-hour
PM2.5 NAAQS by the most expeditious date practicable,
consistent with the requirements of CAA section 189(d). Furthermore,
because the 2015 Serious area attainment date has passed, and the EPA
found that the area failed to attain by the Serious area attainment
date, we are evaluating the State's compliance with the Serious area
plan requirements in light of the attainment date required under CAA
section 189(d).\189\ Thus, we are also proposing to determine that the
Plan meets the Serious area attainment plan requirement under CAA
section 189(b)(1)(A).
---------------------------------------------------------------------------
\189\ See CAA section 179(d); 40 CFR 51.1004(a)(3).
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E. Reasonable Further Progress and Quantitative Milestones
1. Statutory and Regulatory Requirements
CAA section 172(c)(2) provides that all nonattainment area plans
shall require RFP toward attainment. In addition, CAA section 189(c)
requires that all PM2.5 nonattainment area SIPs include
quantitative milestones to be achieved every three years until the area
is redesignated to attainment and that demonstrate RFP. Section 171(l)
of the Act defines RFP as ``such annual incremental reductions in
emissions of the relevant air pollutant as are required by [Part D] or
may reasonably be required by the Administrator for the purpose of
ensuring attainment of the applicable [NAAQS] by the applicable date.''
Neither subpart 1 nor subpart 4 of part D, title I of the Act requires
that states achieve a set percentage of emissions reductions in any
given year for purposes of satisfying the RFP requirement. For purposes
of the PM2.5 NAAQS, the EPA has interpreted the RFP
requirement to require that the nonattainment area plans show annual
incremental emissions reductions sufficient to maintain generally
linear progress toward attainment by the applicable deadline.\190\
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\190\ General Preamble Addendum, 42015.
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Attainment plans for PM2.5 nonattainment areas should
include detailed schedules for compliance with emissions regulations in
the area and provide corresponding annual emissions reductions to be
achieved by each milestone in the schedule.\191\ In reviewing an
attainment plan under subpart 4, the EPA considers whether the annual
incremental emissions reductions to be achieved are reasonable in light
of the statutory objective of timely attainment. Although early
implementation of the most cost-effective control measures is often
appropriate, states should consider both cost-effectiveness and
pollution reduction effectiveness when developing implementation
schedules for control measures and may implement measures that are more
effective at reducing PM2.5 earlier to provide greater
public health benefits.\192\
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\191\ Id. at 42016.
\192\ Id.
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The PM2.5 SIP Requirements Rule establishes specific
regulatory requirements for purposes of satisfying the Act's RFP
requirements and provides related guidance in the preamble to the rule.
Specifically, under the PM2.5 SIP Requirements Rule, each
PM2.5 attainment plan must contain an RFP analysis that
includes, at minimum, the following four components: (1) An
implementation schedule for control measures; (2) RFP projected
emissions for direct PM2.5 and all PM2.5 plan
precursors for each applicable milestone year, based on the anticipated
control measure implementation schedule; (3) a demonstration that the
control strategy and implementation schedule will achieve reasonable
progress toward attainment between the base year and the attainment
year; and (4) a demonstration that by the end of the calendar year for
each milestone date for the area, pollutant emissions will be at levels
that reflect either generally linear progress or stepwise progress in
reducing emissions on an annual basis between the base year and the
attainment year.\193\ Additionally, states should estimate the RFP
projected emissions for each quantitative milestone year by sector on a
pollutant-by-pollutant basis.\194\
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\193\ 40 CFR 51.1012(a).
\194\ 81 FR 58010, 58056.
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Section 189(c) of the Act requires that PM2.5 attainment
plans include quantitative milestones that demonstrate RFP. The purpose
of the quantitative milestones is to allow periodic evaluation of the
area's progress towards attainment of the NAAQS consistent with RFP
requirements. Because RFP is an annual emissions reduction requirement
and the quantitative milestones are to be achieved every three years,
when a state demonstrates compliance with the quantitative milestone
requirement, it should also demonstrate that RFP has been achieved
during each of the relevant three years. Quantitative milestones should
provide an objective means to evaluate progress toward attainment
meaningfully, e.g., through imposition of emissions controls in the
attainment plan and the requirement to quantify those required
emissions reductions. The CAA also requires states to submit milestone
reports (due 90 days after each milestone), and these reports should
include calculations and any assumptions made by the state concerning
how RFP has been met, e.g., through quantification of emissions
reductions to date.\195\
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\195\ General Preamble Addendum, 42016-42017.
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The CAA does not specify the starting point for counting the three-
year periods for quantitative milestones under CAA section 189(c). In
the General Preamble and General Preamble Addendum, the EPA interpreted
the CAA to require that the starting point for the first three-year
period be the due date for the Moderate area plan submission.\196\ In
keeping with this historical approach, the EPA established December 31,
2014, the deadline that the EPA established for a state's submission of
any additional attainment-related SIP elements necessary to satisfy the
subpart 4 Moderate area requirements for the 1997 PM2.5
NAAQS, as the starting point for the first three-year period under CAA
section 189(c) for the 1997 PM2.5 NAAQS in the San Joaquin
Valley.\197\
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\196\ General Preamble, 13539, and General Preamble Addendum,
42016.
\197\ 79 FR 31566 (final rule establishing subpart 4 moderate
area classifications and deadline for related SIP submissions).
Although this final rule did not affect any action that the EPA had
previously taken under CAA section 110(k) on a SIP for a
PM2.5 nonattainment area, the EPA noted that states may
need to submit additional SIP elements to fully comply with the
applicable requirements of subpart 4, even for areas with previously
approved PM2.5 attainment plans, and that the deadline
for any such additional plan submissions was December 31, 2014. Id.
at 31569.
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[[Page 53172]]
Under the PM2.5 SIP Requirements Rule, each attainment
plan submission for an area designated nonattainment for the 1997
PM2.5 NAAQS before January 15, 2015, must contain
quantitative milestones to be achieved no later than three years after
December 31, 2014, and every three years thereafter until the milestone
date that falls within three years after the applicable attainment
date.\198\ If the area fails to attain, this post-attainment date
milestone provides the EPA with the tools necessary to monitor the
area's continued progress toward attainment while the state develops a
new attainment plan.\199\ Quantitative milestones must provide for
objective evaluation of RFP toward timely attainment of the
PM2.5 NAAQS in the area and include, at minimum, a metric
for tracking progress achieved in implementing SIP control measures,
including BACM and BACT, by each milestone date.\200\
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\198\ 40 CFR 51.1013(a)(4).
\199\ 81 FR 58010, 58064.
\200\ Id. at 58064 and 58092.
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Because the EPA designated the San Joaquin Valley area as
nonattainment for the 1997 24-hour PM2.5 NAAQS effective
April 5, 2005,\201\ the plan for this area must contain quantitative
milestones to be achieved no later than three years after December 31,
2014 (i.e., by December 31, 2017), and every three years thereafter
until the milestone date that falls within three years after the
applicable attainment date.\202\ For a Serious area attainment plan
with a statutory attainment date of December 31, 2015, the relevant
quantitative milestone year is December 31, 2017. However, as discussed
in section III, the area did not attain by the statutory Serious area
attainment date and evaluating reasonable further progress toward that
date does not make sense. We are therefore evaluating the Serious area
obligations based on the attainment date the State must meet in a plan
required under CAA section 189(d).\203\ To meet CAA section 189(d), the
SJV PM2.5 Plan includes a demonstration that the area will
attain by December 31, 2020. Therefore, in accordance with 40 CFR
51.1013(a)(4), the attainment plan for this area must contain
quantitative milestones to be achieved no later than December 31, 2017,
December 31, 2020, and December 31, 2023.
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\201\ 70 FR 944.
\202\ 40 CFR 51.1013(a)(4).
\203\ See CAA section 179(d); 40 CFR 51.1004(a)(3).
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2. Summary of the State's Submission
Appendix H (``RFP, Quantitative Milestones, and Contingency'') of
the 2018 PM2.5 Plan contains the State's RFP demonstration
and quantitative milestones for the 1997 24-hour PM2.5
NAAQS,\204\ and the Valley State SIP Strategy contains the control
measure commitments that CARB has identified as mobile source
quantitative milestones for the 2020 milestone date.\205\ Given the
State's conclusions that ammonia, SOX, and VOC emissions do
not contribute significantly to PM2.5 levels that exceed the
1997 24-hour PM2.5 NAAQS in the San Joaquin Valley, as
discussed in section IV.B of this proposed rule, the RFP demonstration
provided by the State addresses emissions of direct PM2.5
and NOX.\206\ Similarly, the State developed quantitative
milestones based upon implementation of control strategy measures in
the adopted SIP and in the SJV PM2.5 Plan that achieve
reductions in emissions of direct PM2.5 and
NOX.\207\ For the 1997 24-hour PM2.5 NAAQS, the
RFP analysis in the Plan shows generally linear progress toward
attainment.
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\204\ As discussed in footnote 34, all references to Appendix H
in this proposed rule are to the revised version submitted on
February 11, 2020, which replaces the version submitted with the
2018 PM2.5 Plan on May 10, 2019.
\205\ Valley State SIP Strategy, Table 7 (identifying State
measures scheduled for action between 2017 and 2020, inter alia) and
CARB Resolution 18-49, ``San Joaquin Valley Supplement to the 2016
State Strategy for the State Implementation Plan'' (October 25,
2018), 5 (adopting State commitment to begin public processes and
propose for Board consideration the list of proposed SIP measures
outlined in the Valley State SIP Strategy and included in Attachment
A, according to the schedule set forth therein).
\206\ SJV PM2.5 Plan, Appendix H, H-1.
\207\ Id. at H-18 and H-19 (District milestones) and H-21 and H-
22 (State milestones).
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We describe the RFP analysis and quantitative milestones in the SJV
PM2.5 Plan in greater detail below.
Reasonable Further Progress
The State addresses the RFP and quantitative milestone requirements
in Appendix H to the 2018 PM2.5 Plan submitted in February
2020. The State estimates that emissions of direct PM2.5 and
NOX will generally decline from the 2013 base year to the
projected 2020 attainment year, and beyond to the 2023 post-attainment
quantitative milestone year. The Plan's emissions inventory shows that
direct PM2.5 and NOX are emitted by a large
number and range of sources in the San Joaquin Valley. Table H-2 in
Appendix H contains an anticipated implementation schedule for District
regulatory control measures and Table 4-8 in Chapter 4 of the 2018
PM2.5 Plan contains an anticipated implementation schedule
for CARB control measures in the San Joaquin Valley. Table H-5 in
Appendix H contains projected emissions for each quantitative milestone
year. These emissions levels reflect baseline emissions projections
through the 2023 post-attainment milestone year.\208\
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\208\ Id. at tables H-3 to H-5.
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The SJV PM2.5 Plan identifies emissions reductions
needed for attainment of the 1997 24-hour PM2.5 NAAQS by
2020,\209\ and identifies San Joaquin Valley's progress toward
attainment in each milestone year.\210\ The State and District set RFP
targets for each of the quantitative milestone years as shown in Table
H-8 of Appendix H of the 2018 PM2.5 Plan.
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\209\ Id. at Table H-6.
\210\ Id. at Table H-7.
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According to the Plan, reductions in both direct PM2.5
and NOX emissions from 2013 base year levels result in
emissions levels consistent with attainment in the 2020 attainment
year. Based on these analyses, the State and District conclude that the
adopted control strategy is adequate to meet the RFP requirement for
the 1997 24-hour PM2.5 NAAQS.
Quantitative Milestones
Appendix H of the 2018 PM2.5 Plan identifies the
milestone dates of December 31, 2017, December 31, 2020, and December
31, 2023, for the 1997 PM2.5 NAAQS.\211\ Appendix H also
identifies target emissions levels to meet the RFP requirement for
direct PM2.5 and NOX emissions for each of these
milestone years,\212\ and State and District control measures that will
achieve emissions reductions in the years leading up to each of the
milestones, in accordance with the control strategy in the Plan.\213\
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\211\ Id. at Table H-12.
\212\ Id. at Table H-8.
\213\ Id. at H-18 and H-19 (District milestones) and H-21 and H-
22 (State milestones).
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The Plan includes quantitative milestones for mobile, stationary,
and area sources. For mobile sources, CARB has developed quantitative
milestones that provide for an evaluation of RFP based on the
implementation of specific control measures by the relevant three-year
milestones. For each quantitative milestone year, the Plan provides for
evaluating RFP by tracking State and District implementation of
regulatory measures and SIP commitments during the three-year period
leading to each
[[Page 53173]]
milestone date, consistent with the control strategy in the SJV
PM2.5 Plan.\214\ The identified regulatory measures include
State measures for light-duty vehicles and non-road vehicles and
several District measures for stationary and area sources.\215\
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\214\ Id. We note that the District's identified quantitative
milestones for 2023 appear to contain a typographical error, as they
include a District report on ``[t]he status of SIP measures adopted
between 2017 and 2020 as per the schedule included in the adopted
Plan.'' Id. at H-18 and H-19. We understand that the District
intended to refer here to the status of SIP measures adopted between
2020 and 2023, consistent with the schedule in the 2018
PM2.5 Plan.
\215\ Id. at H-18 and H-19 (District milestones), and H-21 and
H-22 (State milestones).
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CARB submitted its 2017 Quantitative Milestone Report for the San
Joaquin Valley to the EPA on December 20, 2018.\216\ The report
includes a certification that CARB and the District met the 2017
quantitative milestones identified in the SJV PM2.5 Plan for
the 1997 PM2.5 NAAQS and discusses the State's and
District's progress on implementing the three CARB measures and six
District measures identified in Appendix H as quantitative milestones
for the 2017 milestone year. On February 15, 2021, the EPA determined
that the 2017 Quantitative Milestone Report was adequate.\217\ In our
evaluation of the 2017 Quantitative Milestone Report, we found that the
control measures in the Plan are in effect, consistent with the RFP
demonstration in the SJV PM2.5 Plan for the 1997 24-hour
PM2.5 NAAQS, but we noted that the determination of adequacy
did not constitute approval of any component of the SJV
PM2.5 Plan.\218\
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\216\ Letter dated December 20, 2018, from Richard W. Corey,
Executive Officer, CARB, to Michael Stoker, Regional Administrator,
EPA Region IX, with attachment ``2017 Quantitative Milestone Report
for the 1997 and 2006 NAAQS.''
\217\ Letter dated February 15, 2021, from Deborah Jordan,
Acting Regional Administrator, EPA Region IX, to Richard W. Corey,
Executive Officer, CARB, with enclosure titled ``EPA Evaluation of
2017 Quantitative Milestone Report.''
\218\ Id.
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3. The EPA's Review of the State's Submission
The RFP demonstration in the SJV PM2.5 Plan identifies
quantitative milestone dates (i.e., December 31 of 2017, 2020, and
2023) that are consistent with the requirements of 40 CFR 51.1013(a)(4)
and presents projected RFP emissions levels for direct PM2.5
and NOX to be achieved by these milestone dates based on the
implementation schedule for existing control measures in the area
(i.e., baseline measures). The projected emissions levels based on the
implementation schedule in the Plan demonstrate that the control
strategy will achieve direct PM2.5 and NOX
emissions reductions at rates representing generally linear progress
towards attainment between the 2013 baseline year and the 2020
attainment year. The target emissions levels and associated control
requirements provide for objective evaluation of the area's progress
towards attainment of the 1997 24-hour PM2.5 NAAQS.
The State's quantitative milestones in Appendix H are to implement
specific measures listed in the State's control measure commitments
that apply to heavy-duty trucks and buses, light-duty vehicles, and
non-road equipment sources and may provide substantial reductions in
emissions of direct PM2.5 and NOX from mobile
sources in the San Joaquin Valley. Similarly, the District's
quantitative milestones in Appendix H are to implement specific
measures listed in the District's control measure commitments that
apply to sources such as residential wood burning, commercial
charbroiling, glass melting furnaces, and internal combustion engines,
and that may provide substantial reductions in emissions of direct
PM2.5 and NOX from stationary sources. These
milestones provide an objective means for tracking the State's and
District's progress in implementing their respective control strategies
and, thus, provide for objective evaluation of the San Joaquin Valley's
progress toward timely attainment.
For these reasons, we propose to determine that the SJV
PM2.5 Plan satisfies the requirements for RFP in CAA section
172(c)(2) and 40 CFR 51.1012 and for quantitative milestones in CAA
section 189(c) and 40 CFR 51.1013 for the 1997 24-hour PM2.5
NAAQS in the San Joaquin Valley for purposes of both the Serious area
and CAA section 189(d) attainment plans. Because we are proposing to
determine that the San Joaquin Valley has attained the 1997 24-hour
PM2.5 NAAQS by the December 31, 2020 attainment date, as
discussed in section V of this proposed rule, we are also proposing to
determine that the requirement for a post-attainment milestone will no
longer apply in the San Joaquin Valley nonattainment area for these
NAAQS. As described in section IV.E.1 above, the purpose of the post-
attainment quantitative milestone is to provide the EPA with the tools
necessary to monitor the area's continued progress toward attainment in
the event the area fails to attain by the attainment date.\219\ Once an
area has attained the NAAQS, ``no further milestones are necessary or
meaningful.'' \220\ Similarly, the section 189(c)(2) requirement to
submit a quantitative milestone report no longer applies when the area
has attained the standard.\221\ Accordingly, upon a final determination
that the San Joaquin Valley area has attained the 1997 24-hour
PM2.5 NAAQS by the attainment date, the post-attainment RFP
milestone will no longer have purpose and the EPA is proposing to find
that the requirement will no longer apply to the San Joaquin Valley. If
we finalize this action as proposed, the State will no longer be
required to submit a quantitative milestone report for the San Joaquin
Valley under 40 CFR 51.1013(b) for the purposes of the 2023 post-
attainment milestone year identified in the Plan for the 1997 24-hour
PM2.5 NAAQS.
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\219\ 81 FR 58010, 58064.
\220\ 75 FR 13710, 13713 (March 23, 2010).
\221\ Id.
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F. Contingency Measures
1. Requirements for Contingency Measures
Under CAA section 172(c)(9), each state required to make a
nonattainment plan SIP submission must include, in such plan,
contingency measures to be implemented if an area fails to meet RFP
(``RFP contingency measures'') or fails to attain the NAAQS by the
applicable attainment date (``attainment contingency measures''). Under
the PM2.5 SIP Requirements Rule, states must include
contingency measures that will be implemented following a determination
by the EPA that the state has failed: (1) To meet any RFP requirement
in the approved SIP; (2) to meet any quantitative milestone in the
approved SIP; (3) to submit a required quantitative milestone report;
or (4) to attain the applicable PM2.5 NAAQS by the
applicable attainment date.\222\ Contingency measures must be fully
adopted rules or control measures that are ready to be implemented
quickly upon failure to meet RFP or failure of the area to meet the
relevant NAAQS by the applicable attainment date.\223\
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\222\ 40 CFR 51.1014(a).
\223\ 81 FR 58010, 58066 and General Preamble Addendum, 42015.
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The purpose of contingency measures is to continue progress in
reducing emissions while a state revises its SIP to meet the missed RFP
requirement or to correct ongoing nonattainment. Neither the CAA nor
the EPA's implementing regulations establish a specific level of
emissions reductions that implementation of contingency measures must
achieve, but the EPA recommends that contingency measures provide for
emissions reductions
[[Page 53174]]
equivalent to approximately one year of reductions needed for RFP in
the nonattainment area at issue, calculated as the overall level of
reductions needed to demonstrate attainment divided by the number of
years from the base year to the attainment year. In general, we expect
all actions needed to effect full implementation of the measures to
occur within 60 days after the EPA notifies the state of a failure to
meet RFP or to attain.\224\
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\224\ 81 FR 58010, 58066. See also General Preamble, 13512,
13543-13544, and General Preamble Addendum, 42014-42015.
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To satisfy the requirements of 40 CFR 51.1014, the contingency
measures adopted as part of a PM2.5 attainment plan must
consist of control measures for the area that are not otherwise
required to meet other nonattainment plan requirements (e.g., to meet
RACM/RACT requirements) and must specify the timeframe within which
their requirements become effective following any of the EPA
determinations specified in 40 CFR 51.1014(a). In a 2016 decision
called Bahr v. EPA (``Bahr''),\225\ the Ninth Circuit Court of Appeals
rejected the EPA's interpretation of CAA section 172(c)(9) to allow
approval of already-implemented control measures as contingency
measures. In Bahr, the Ninth Circuit concluded that contingency
measures must be measures that are triggered and implemented only after
the EPA determines that an area failed to meet RFP requirements or to
attain by the applicable attainment date. Thus, within the geographic
jurisdiction of the Ninth Circuit, already implemented measures cannot
serve as contingency measures under CAA section 172(c)(9).\226\ To
comply with section 172(c)(9), a state must develop, adopt, and submit
a contingency measure to be triggered upon a failure to meet an RFP
milestone, failure to meet a quantitative milestone requirement, or
failure to attain the NAAQS by the applicable attainment date.
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\225\ Bahr v. EPA, 836 F.3d 1218, 1235-1237 (9th Cir. 2016).
\226\ See also Sierra Club v. EPA, 985 F.3d 1055 (D.C. Cir.
2021) and Assoc. of Irritated Residents v. EPA, No. 19-71223, slip
op. (9th Cir. Aug 26, 2021).
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2. Summary of the State's Submission
The SJV PM2.5 Plan addresses the contingency measure
requirement for the 1997 24-hour PM2.5 NAAQS in section 5.6
and Appendix H (specifically, section H.3 (``Contingency Measures''))
of the 2018 PM2.5 Plan. The Plan relies on revisions to the
District's wood-burning rule (Rule 4901) and refers to a SIP revision
submitted by CARB on October 23, 2017, titled ``State Implementation
Plan Attainment Contingency Measures for the San Joaquin Valley 15
[mu]g/m\3\ Annual PM2.5 NAAQS'' (``2017 Contingency Measure
SIP'').\227\ On March 19, 2021, CARB withdrew the 2017 Contingency
Measure SIP submission.\228\ Therefore, we are not evaluating the 2017
Contingency Measure SIP as part of this action.
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\227\ Letter dated October 23, 2017, from Richard W. Corey,
Executive Officer, CARB, to Alexis Strauss, Acting Regional
Administrator, EPA Region 9.
\228\ Letter dated March 19, 2021, from Richard W. Corey,
Executive Officer, CARB, to Deborah Jordan, Acting Regional
Administrator, EPA Region 9, transmitting CARB Executive Order S-21-
004.
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With respect to the District contingency measure, the 2018
PM2.5 Plan states that the District will amend Rule 4901 to
include a requirement that would be triggered upon a determination by
the EPA that the San Joaquin Valley failed to meet a regulatory
requirement necessitating implementation of a contingency measure.\229\
The District adopted amendments to Rule 4901 on June 20, 2019,
including a contingency measure in section 5.7.3 of the amended rule
(more details below). In the EPA's July 22, 2020 final action to
approve Rule 4901, as amended June 20, 2019, we did not evaluate
section 5.7.3 of the amended rule for compliance with CAA requirements
for contingency measures.\230\ On July 22, 2021, the EPA proposed to
find that the contingency provision of Rule 4901 (section 5.7.3) does
not satisfy the CAA requirements for contingency measures for the 1997
annual PM2.5 NAAQS and proposed to remove the provision from
the SIP because it is severable from the remainder of Rule 4901.\231\
In this action, we evaluate section 5.7.3 of Rule 4901 for compliance
with the contingency measures requirements for purposes of the 1997 24-
hour PM2.5 NAAQS.
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\229\ 2018 PM2.5 Plan, Appendix H, H-25.
\230\ 85 FR 44206 (final approval of Rule 4901); 85 FR 1131,
1132-1133 (January 9, 2020) (proposed approval of Rule 4901).
\231\ 86 FR 38652.
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Rule 4901 is designed to limit emissions generated by the use of
wood burning fireplaces, wood burning heaters, and outdoor wood burning
devices. The rule establishes requirements for the sale/transfer,
operation, and installation of wood burning devices and for advertising
the sale of seasoned wood consistent with a moisture content limit
within the San Joaquin Valley. The rule includes a two-tiered, episodic
wood burning curtailment requirement that applies during four winter
months, November through February. During a level one episodic wood
burning curtailment, section 5.7.1 prohibits any person from operating
a wood burning fireplace or unregistered wood burning heater, but
permits the use of a properly operated wood burning heater that meets
certification requirements and has a current registration with the
District. Sections 5.9 through 5.11 impose specific registration
requirements on any person operating a wood burning fireplace or wood
burning heater and section 5.12 imposes specific certification
requirements on wood burning heater professionals. During a level two
episodic wood burning curtailment, operation of any wood burning device
is prohibited by section 5.7.2.
Prior to the 2019-2020 wood burning season, the District imposed a
level one curtailment when the PM2.5 concentration was
forecasted to be between 20 [mu]g/m\3\ and 65 [mu]g/m\3\ and imposed a
level two curtailment when the PM2.5 concentration was
forecasted to be above 65 [mu]g/m\3\ or the PM10
concentration was forecasted to be above 135 [mu]g/m\3\. In 2019 the
District adopted revisions to Rule 4901 to lower the wood burning
curtailment thresholds in the ``hot spot'' counties of Madera, Fresno,
and Kern. The District lowered the level one PM2.5 threshold
for these three counties from 20 [mu]g/m\3\ to 12 [mu]g/m\3\, and the
level two PM2.5 threshold from 65 [mu]g/m\3\ to 35 [mu]g/
m\3\. The District did not modify the curtailment thresholds for other
counties in the San Joaquin Valley--those levels remain at 20 [mu]g/
m\3\ for level one and 65 [mu]g/m\3\ for level two.
The District's 2019 revision to Rule 4901 also included the
addition of a contingency measure in section 5.7.3 of the rule,
requiring that 60 days following the effective date of an EPA
determination that the San Joaquin Valley has failed to attain the
1997, 2006, or 2012 PM2.5 NAAQS by the applicable attainment
date, the PM2.5 curtailment levels of any county that has
failed to attain the applicable standard will be lowered to the
curtailment levels in place for hot spot counties. The District
estimates that the potential emissions reduction of direct
PM2.5 would be in the range of 0.014 tpd (if the contingency
measure is triggered in Kings County but not the other non-hot spot
counties) to 0.387 tpd (if the contingency measure is triggered in all
five of the non-hot spot counties), but there would be no emissions
reduction if, at the time of the determination of failure to attain the
1997 24-hour PM2.5 NAAQS by the attainment date, violations
of the 1997 24-hour PM2.5
[[Page 53175]]
NAAQS are observed only at monitors in the hot spot counties.\232\ The
corresponding potential NOX emissions reduction would be in
the range of 0.002 tpd to 0.060 tpd, respectively, but once again,
there would be no emissions reduction if the violations are monitored
in the hot spot counties only.\233\ The EPA has already approved Rule
4901, as amended in 2019, as a revision to the California SIP.\234\
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\232\ See Table B-13 in Appendix B from the District's Final
Staff Report (June 20, 2019) for revisions to Rule 4901.
\233\ NOX emissions reductions from the contingency
measure are based on the District's estimates for direct
PM2.5 emissions using the ratio of direct
PM2.5 to NOX in Table 1, page 8, of the
District's Final Staff Report (June 20, 2019) for revisions to Rule
4901.
\234\ 85 FR 44206.
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3. The EPA's Review of the State's Submission
As noted above, the EPA previously proposed to find that the
contingency provision of Rule 4901 (section 5.7.3) does not satisfy the
CAA requirements for contingency measures for the 1997 annual
PM2.5 NAAQS.\235\ As part of that proposal, the EPA found
that the measure meets some, but not all, of the applicable
requirements for contingency measures under CAA section 172(c)(9) and
40 CFR 51.1014. One of the deficiencies outlined in our proposal was
that the contingency provisions of Rule 4901 do not address the
potential for State failures to meet RFP, to meet a quantitative
milestone, or to submit a quantitative milestone report. In addition,
the contingency measure provisions of Rule 4901 are not structured to
achieve any additional emissions reductions if the EPA were to find
that the monitoring locations in the ``hot spot'' counties (i.e.,
Fresno, Kern, or Madera) are the only counties in the San Joaquin
Valley that are violating the 1997 24-hour PM2.5 NAAQS as of
the attainment date. To qualify as a contingency measure, a measure
must be structured to achieve emissions reductions if triggered;
however, the contingency provisions of Rule 4901 provide for such
reductions only under certain circumstances.
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\235\ 86 FR 38652.
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Consistent with our proposal for the 1997 annual PM2.5
NAAQS and for these same reasons, we are proposing to disapprove the
contingency measure element of the SJV PM2.5 Plan for the
1997 24-hour PM2.5 NAAQS as not meeting the requirements of
172(c)(9) and 40 CFR 51.1014 for Serious area and section 189(d)
attainment plans. However, the EPA is also proposing to find that the
contingency measures are no longer required for the San Joaquin Valley
nonattainment area for the 1997 24-hour PM2.5 NAAQS, for the
reasons discussed below.
Attainment contingency measures under 172(c)(9) are triggered upon
the EPA's determination that an area failed to attain a given NAAQS by
its applicable attainment date. CAA section 179(c) requires the EPA to
determine whether the area attained the NAAQS by its applicable
attainment date. As part of this proposed action, we are proposing to
determine that the San Joaquin Valley nonattainment area attained the
1997 24-hour PM2.5 NAAQS by the December 31, 2020 attainment
date projected by the Plan. Based on our proposed finding of attainment
by the applicable attainment date, we are also proposing to determine
that the CAA requirement for the SIP to provide for attainment
contingency measures will no longer apply to the San Joaquin Valley for
the 1997 24-hour PM2.5 NAAQS. Under CAA section 172(c)(9),
attainment contingency measures are implemented only if the area fails
to attain by the attainment date. Therefore, if we finalize the
determination that the San Joaquin Valley nonattainment area has
attained the 1997 24-hour PM2.5 NAAQS, attainment
contingency measures for this NAAQS would never be required to be
implemented. Because there are no circumstances under which CAA section
172(c)(9) attainment contingency measures could ever be triggered, we
think it is a reasonable interpretation of the CAA that these measures
are no longer required to be submitted.\236\
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\236\ See Bahr v. Regan, No. 20-70092, (9th Cir. July 28, 2021),
slip op. 45-51.
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Similarly, we are proposing to find that, upon finalization of the
determination of attainment by the attainment date, the RFP related
contingency measure requirement (i.e., for failure to meet RFP, to
submit a quantitative milestone report, or to meet the quantitative
milestone) would also no longer apply to the San Joaquin Valley
nonattainment area for the 1997 24-hour PM2.5 NAAQS. The
purpose of the RFP and related quantitative milestone requirements
under the CAA is to ``ensure[e] attainment of the applicable [NAAQS] by
the applicable date.'' \237\ Because the sole purpose of RFP
contingency measures is to provide continued progress if an area fails
to meet its RFP or quantitative milestone requirements, a final
determination of attainment by the attainment date serves as
demonstration that RFP requirements for the area have been met, and
that there is no need for any later quantitative milestone or milestone
report, and thus the RFP related contingency measures are no longer
needed. Accordingly, because we are proposing to determine that the San
Joaquin Valley has attained the 1997 24-hour PM2.5 NAAQS by
the December 31, 2020 attainment date, and that therefore the RFP and
quantitative milestone requirements would no longer apply, we are now
also proposing to determine that RFP contingency measures are no longer
required for this area.\238\
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\237\ CAA section 171(c).
\238\ With respect to the 2017 RFP contingency measure
requirement specifically, we note that, as explained in section
IV.E.2 of this proposed rule, on December 20, 2018, CARB submitted a
quantitative milestone report demonstrating that the 2017
quantitative milestones in the SJV PM2.5 Plan have been
achieved, and the EPA has determined that this milestone report is
adequate. Because the State and District have demonstrated that the
San Joaquin Valley area has met its 2017 quantitative milestones,
RFP contingency measures for the 2017 milestone year would never be
triggered.
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Under section 179(a) of the CAA, final disapproval of a SIP
submission that addresses a requirement of part D, title I of the CAA,
or is required in response to a finding of substantial inadequacy as
described in CAA section 110(k)(5) (SIP Call), starts sanctions clocks.
The SJV PM2.5 Plan, including the contingency measure
element, does address requirements of part D. However, if we finalize
our determinations that the requirements for contingency measures no
longer apply to the San Joaquin Valley nonattainment area for the 1997
24-hour PM2.5 NAAQS, then the contingency measure element of
the SJV PM2.5 Plan would no longer be required to address
any part D requirement for the 1997 24-hour PM2.5 NAAQS.
Therefore, final disapproval of the contingency measure element of the
SJV PM2.5 Plan would not trigger sanctions clocks.
Similarly, final disapproval would not trigger any obligation for the
EPA to promulgate a federal implementation plan (FIP) under CAA section
110(c) because there would be no deficiency for such a FIP to
correct.\239\
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\239\ This is the case for both the Serious area plan and the
section 189(d) plan. Because the purpose of contingency measures is
to ensure continued progress toward attainment in the event that an
area fails to attain the NAAQS or meet RFP requirements, and we are
proposing to find that the area has meet the 1997 24-hour
PM2.5 NAAQS, there is no purpose to triggering sanction
and FIP obligations for the State to submit measures to achieve the
goal of attaining the 1997 24-hour PM2.5 NAAQS when this
goal has already been met.
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Because we are proposing to approve the RFP analysis, the modeled
attainment demonstration, and the motor vehicle emissions budgets, we
are also proposing to issue a protective finding under 40 CFR
93.120(a)(3) in the event we finalize the disapproval of the
[[Page 53176]]
contingency measures. Without a protective finding, the final
disapproval would result in a conformity freeze, under which only
projects in the first four years of the most recent conforming Regional
Transportation Plan (RTP) and Transportation Improvement Programs
(TIPs) can proceed. During a freeze, no new RTPs, TIPs, or RTP/TIP
amendments can be found to conform.\240\ Under this protective finding,
however, the final disapproval of the contingency measures does not
result in a transportation conformity freeze in the San Joaquin Valley
PM2.5 nonattainment area.
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\240\ 40 CFR 93.120(a)(2).
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If the State chooses to withdraw the contingency measure element
with respect to the 1997 24-hour PM2.5 NAAQS prior to our
final action on the SJV PM2.5 Plan for that NAAQS, we would
take no final action either to approve or to disapprove that element.
G. Motor Vehicle Emission Budgets
1. Statutory and Regulatory Requirements
Section 176(c) of the CAA requires federal actions in nonattainment
and maintenance areas to conform to the goals of the state's SIP to
eliminate or reduce the severity and number of violations of the NAAQS
and achieve timely attainment of the NAAQS. Conformity to the SIP's
goals means that such actions will not: (1) Cause or contribute to
violations of a NAAQS, (2) worsen the severity of an existing
violation, or (3) delay timely attainment of any NAAQS or any interim
milestone.
Actions involving Federal Highway Administration (FHWA) or Federal
Transit Administration (FTA) funding or approval are subject to the
EPA's transportation conformity rule, codified at 40 CFR part 93,
subpart A. Under this rule, metropolitan planning organizations (MPOs)
in nonattainment and maintenance areas coordinate with state and local
air quality and transportation agencies, the EPA, the FHWA, and the FTA
to demonstrate that an area's regional transportation plans (RTPs) and
transportation improvement programs conform to the applicable SIP. This
demonstration is typically done by showing that estimated emissions
from existing and planned highway and transit systems are less than or
equal to the motor vehicle emission budgets (MVEBs or ``budgets'')
contained in all control strategy SIPs. Budgets are generally
established for specific years and specific pollutants or precursors
and must reflect all of the motor vehicle control measures contained in
the attainment and RFP demonstrations.\241\
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\241\ 40 CFR 93.118(e)(4)(v).
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Under the PM2.5 SIP Requirements Rule, Serious area
PM2.5 attainment plans must include appropriate quantitative
milestones and projected RFP emissions levels for direct
PM2.5 and all PM2.5 plan precursors in each
milestone year.\242\ For an area designated nonattainment for the 1997
PM2.5 NAAQS before January 15, 2015, the attainment plan
must contain quantitative milestones to be achieved no later than three
years after December 31, 2014, and every three years thereafter until
the milestone date that falls within three years after the applicable
attainment date.\243\ As the EPA explained in the preamble to the
PM2.5 SIP Requirements Rule, it is important to include a
post-attainment year quantitative milestone to ensure that, if the area
fails to attain by the attainment date, the EPA can continue to monitor
the area's progress toward attainment while the state develops a new
attainment plan.\244\ Although the post-attainment year quantitative
milestone is a required element of a Serious area plan, it is not
necessary to demonstrate transportation conformity for 2023 or to use
the 2023 budgets in transportation conformity determinations until such
time as the area fails to attain the 1997 24-hour PM2.5
NAAQS.
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\242\ 40 CFR 51.1012(a), 51.1013(a)(1).
\243\ 40 CFR 51.1013(a)(4) and 81 FR 58010, 58058 and 58063-
58064. Because the area has failed to attain the 1997 24-hour
PM2.5 NAAQS by the Serious area attainment date, and it
would serve no purpose for the plan to include budgets for the EPA
to evaluate conformity for the dates associated with the Serious
area attainment date, the applicable attainment date for the
purposes of our evaluation is the section 189(d) projected
attainment date of December 31, 2020.
\244\ 81 FR 58010, 58063-58064.
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PM2.5 plans should identify budgets for direct
PM2.5, NOX, and all other PM2.5
precursors for which on-road emissions are determined to significantly
contribute to PM2.5 levels in the area for each RFP
milestone year and the attainment year, if the plan demonstrates
attainment. All direct PM2.5 SIP budgets should include
direct PM2.5 motor vehicle emissions from tailpipes, brake
wear, and tire wear. With respect to PM2.5 from re-entrained
road dust and emissions of VOC, SO2, and/or ammonia, the
transportation conformity provisions of 40 CFR part 93, subpart A,
apply only if the EPA Regional Administrator or the director of the
state air agency has made a finding that emissions of these pollutants
within the area are a significant contributor to the PM2.5
nonattainment problem and has so notified the MPO and Department of
Transportation (DOT), or if the applicable implementation plan (or
implementation plan submission) includes any of these pollutants in the
approved (or adequate) budget as part of the RFP, attainment, or
maintenance strategy.\245\
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\245\ 40 CFR 93.102(b)(3), 93.102(b)(2)(v), and 93.122(f); see
also Conformity Rule preambles at 69 FR 40004, 40031-40036 (July 1,
2004), 70 FR 24280, 24283-24285 (May 6, 2005) and 70 FR 31354 (June
1, 2005).
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By contrast, transportation conformity requirements apply with
respect to emissions of NOX unless both the EPA Regional
Administrator and the director of the state air agency have made a
finding that transportation-related emissions of NOX within
the nonattainment area are not a significant contributor to the
PM2.5 nonattainment problem and have so notified the MPO and
DOT, or the applicable implementation plan (or implementation plan
submission) does not establish an approved (or adequate) budget for
such emissions as part of the RFP, attainment, or maintenance
strategy.\246\
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\246\ 40 CFR 93.102(b)(2)(iv).
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It is not always necessary for states to establish motor vehicle
emissions budgets for all PM2.5 precursors. The
PM2.5 SIP Requirements Rule allows a state to demonstrate
that emissions of certain precursors do not contribute significantly to
PM2.5 levels that exceed the NAAQS in a nonattainment area,
in which case the state may exclude such precursor(s) from its control
evaluations for the specific NAAQS at issue. If a state successfully
demonstrates that the emissions of one or more of the PM2.5
precursors from all sources do not contribute significantly to
PM2.5 levels in the subject area, then it is not necessary
to establish motor vehicle emissions budgets for such precursor(s).
Alternatively, the transportation conformity regulations contain
criteria for determining whether emissions of one or more
PM2.5 precursors are insignificant for transportation
conformity purposes.\247\ For a pollutant or precursor to be considered
an insignificant contributor based on the transportation conformity
rule's criteria, the control strategy SIP must demonstrate that it
would be unreasonable to expect that such an area would experience
enough motor vehicle emissions growth in that pollutant and/or
precursor for a NAAQS violation to occur. Insignificance determinations
are based on factors such as air quality, SIP motor vehicle control
measures, trends
[[Page 53177]]
and projections of motor vehicle emissions, and the percentage of the
total attainment plan emissions inventory for the NAAQS at issue that
is comprised of motor vehicle emissions. The EPA's rationale for
providing for insignificance determinations is described in the July 1,
2004 revision to the Transportation Conformity Rule.\248\
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\247\ 40 CFR 93.109(f).
\248\ 69 FR 40004.
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Transportation conformity trading mechanisms are allowed under 40
CFR 93.124 where a state establishes appropriate mechanisms for such
trades. The basis for the trading mechanism is the SIP attainment
modeling that establishes the relative contribution of each
PM2.5 precursor pollutant. The applicability of emissions
trading between conformity budgets for conformity purposes is described
in 40 CFR 93.124(c).
The EPA's process for determining the adequacy of a budget consists
of three basic steps: (1) Notifying the public of a SIP submittal; (2)
providing the public the opportunity to comment on the budget during a
public comment period; and (3) making a finding of adequacy or
inadequacy. The EPA can notify the public by either posting an
announcement that the EPA has received SIP budgets on the EPA's
adequacy website,\249\ or through a Federal Register notice of proposed
rulemaking when the EPA reviews the adequacy of an implementation plan
budget simultaneously with its review and action on the SIP
itself.\250\
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\249\ 40 CFR 93.118(f)(1).
\250\ 40 CFR 93.118(f)(2).
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2. Summary of the State's Submission
The 2018 PM2.5 Plan includes budgets for direct
PM2.5 and NOX emissions, calculated using annual
average daily emissions, for 2017, 2020, and 2023 (RFP milestone year,
attainment year, and post-attainment quantitative milestone year,
respectively).\251\ The Plan establishes separate direct
PM2.5 and NOX subarea budgets for each county,
and partial county (for Kern County), in the San Joaquin Valley.\252\
CARB calculated the budgets using EMFAC2014, CARB's latest version of
the EMFAC model for estimating emissions from on-road vehicles
operating in California that was available at the time of Plan
development, and the latest modeled vehicle miles traveled and speed
distributions from the San Joaquin Valley MPOs from the Final 2017
Federal Transportation Improvement Program, adopted in September 2016.
The budgets reflect annual average emissions because those emissions
are linked with the District's attainment demonstration for the 1997
24-hour PM2.5 NAAQS.
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\251\ 2018 PM2.5 Plan, Appendix D, Table 3-1.
\252\ 40 CFR 93.124(c) and (d).
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The direct PM2.5 budgets include tailpipe, brake wear,
and tire wear emissions but do not include paved road dust, unpaved
road dust, and road construction dust emissions.\253\ The State is not
required to include re-entrained road dust in the budgets under section
93.103(b)(3) unless the EPA or the State has made a finding that these
emissions are significant. Neither the State nor the EPA has made such
a finding, but the Plan does include a discussion of the significance/
insignificance factors for re-entrained road dust.\254\ The budgets
included in the 2018 PM2.5 Plan for purposes of the 1997 24-
hour PM2.5 NAAQS are shown in Table 8.
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\253\ 2018 PM2.5 Plan, Appendix D, D-122 and D-123.
\254\ Id. at D-121 and D-122.
Table 8--Motor Vehicle Emission Budgets for the San Joaquin Valley for the 1997 24-Hour PM2.5 NAAQS
[Annual average, tpd]
--------------------------------------------------------------------------------------------------------------------------------------------------------
2017 (RFP year) 2020 (Attainment year) 2023 (Post-attainment year)
County -----------------------------------------------------------------------------------------------
PM2.5 NOX PM2.5 NOX PM2.5 NOX
--------------------------------------------------------------------------------------------------------------------------------------------------------
Fresno.................................................. 0.9 28.5 0.9 25.3 0.8 15.1
Kern.................................................... 0.8 28.0 0.8 23.3 0.7 13.3
Kings................................................... 0.2 5.8 0.2 4.8 0.2 2.8
Madera.................................................. 0.2 5.3 0.2 4.2 0.2 2.5
Merced.................................................. 0.3 10.7 0.3 8.9 0.3 5.3
San Joaquin............................................. 0.7 14.9 0.6 11.9 0.6 7.6
Stanislaus.............................................. 0.4 11.9 0.4 9.6 0.4 6.1
Tulare.................................................. 0.4 10.8 0.4 8.5 0.4 5.2
--------------------------------------------------------------------------------------------------------------------------------------------------------
Source: 2018 PM2.5 Plan, Appendix D, Table 3-1. Budgets are rounded to the nearest tenth of a ton.
The State did not include budgets for VOC, SO2, or
ammonia. As discussed in section IV.B of this preamble, the State
submitted a PM2.5 precursor demonstration documenting its
conclusion that control of these precursors would not significantly
contribute to attainment of the 1997 24-hour PM2.5 NAAQS,
and the EPA is proposing to approve the precursor demonstration.
Therefore, if the EPA approves the demonstration, the State would not
be required to submit budgets for these precursors. The State included
a discussion of the significance/insignificance factors for ammonia,
SO2, and VOC to demonstrate a finding of insignificance
under the transportation conformity rule.\255\
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\255\ 40 CFR 93.109(f).
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In the submittal letter for the 2018 PM2.5 Plan, CARB
requested that the EPA limit the duration of the approval of the
budgets to the period before the effective date of the EPA's adequacy
finding for any subsequently submitted budgets.\256\
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\256\ Letter dated May 9, 2019, from Richard W. Corey, Executive
Officer, CARB, to Mike Stoker, Regional Administrator, EPA Region 9,
3.
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Conformity Trading Mechanism
The 2018 PM2.5 Plan also includes a proposed trading
mechanism for transportation conformity analyses that would allow
future decreases in NOX emissions from on-road mobile
sources to offset any on-road increases in direct PM2.5
emissions. The State is proposing to use a 2 to 1 NOX to
PM2.5 ratio for the 1997 24-hour PM2.5 NAAQS.
This ratio was derived by performing a sensitivity analysis based on a
30 percent reduction of NOX or PM2.5 emissions
and calculating the corresponding effect on design values at sites in
Bakersfield and Fresno.
To ensure that the trading mechanism does not affect the ability of
the San Joaquin Valley to meet the NOX budget, the
NOX emissions reductions available to supplement the
PM2.5 budget would
[[Page 53178]]
only be those remaining after the NOX budget has been
met.\257\ The Plan also provides that the San Joaquin Valley MPOs shall
clearly document the calculations used in the trading, along with any
additional reductions of NOX and PM2.5 emissions
in the conformity analysis.
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\257\ 2018 PM2.5 Plan, Appendix D, D-126 and D-127.
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3. The EPA's Review of the State's Submission
The EPA generally first conducts a preliminary review of budgets
submitted with an attainment or maintenance plan for PM2.5
for adequacy, prior to taking action on the plan itself, and did so
with respect to the PM2.5 budgets in the 2018
PM2.5 Plan. On June 18, 2019, the EPA announced the
availability of the 2018 PM2.5 Plan with MVEBs and a 30-day
public comment period. This announcement was posted on the EPA's
Adequacy website at: https://www.epa.gov/state-and-local-transportation/state-implementation-plans-sip-submissions-currently-under-epa. The comment period for this notification ended on July 18,
2019. We did not receive any comments during this comment period.
Based on our proposal to approve the State's demonstration that
emissions of ammonia, SO2, and VOCs do not contribute
significantly to PM2.5 levels that exceed the 1997 24-hour
PM2.5 NAAQS in the San Joaquin Valley, as discussed in
section IV.B of this proposal, and the information about ammonia,
SO2, and VOC emissions in the Plan, the EPA proposes to find
that it is not necessary to establish motor vehicle emissions budgets
for transportation-related emissions of ammonia, SO2, and
VOC to attain the 1997 24-hour PM2.5 NAAQS in the San
Joaquin Valley. Based on the information about re-entrained road dust
in the Plan and in accordance with 40 CFR 93.102(b)(3), the EPA
proposes to find that it is not necessary to include re-entrained road
dust emissions in the budgets for 1997 24-hour PM2.5 NAAQS
in the San Joaquin Valley.
For the reasons discussed in sections IV.D and IV.E of this
proposed rule, the EPA is proposing to approve the attainment and RFP
demonstrations, respectively, in the SJV PM2.5 Plan. The
2017 RFP and 2020 attainment year budgets, as shown in Table 8 of this
preamble, are consistent with these demonstrations, are clearly
identified and precisely quantified, and meet all other applicable
statutory and regulatory requirements including the adequacy criteria
in 40 CFR 93.118(e)(4). For these reasons, the EPA proposes to approve
the 2017 and 2020 budgets listed in Table 8.\258\ We provide a more
detailed discussion in section IV of the EPA's 1997 24-hour
PM2.5 TSD. The budgets that the EPA is proposing to approve
relate only to the 1997 24-hour PM2.5 NAAQS, and our
proposed approval does not affect the status of the budgets for the
1997 annual PM2.5 NAAQS or the previously-approved MVEBs for
the 2006 PM2.5 NAAQS and related trading mechanism, which
remain in effect for that PM2.5 NAAQS.
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\258\ Although we are proposing to approve the 2017 budgets, we
note that these budgets would not be used in any future
transportation conformity determinations because the Plan contains
budgets for 2020.
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Although the post-attainment year quantitative milestone is a
required element of the Serious area plan, it is not necessary to
demonstrate transportation conformity for 2023 or to use the 2023
budgets in transportation conformity determinations until such time as
the area fails to attain the 1997 24-hour PM2.5 NAAQS. As
discussed in section V of this document, the EPA is proposing to find
that the San Joaquin Valley area has attained the 1997 24-hour
PM2.5 NAAQS. The EPA does not believe that it is necessary
to demonstrate conformity using post-attainment year budgets in areas
that attain by the attainment date. Therefore, if the EPA finalizes the
determination that the San Joaquin Valley area attained by the December
31, 2020 attainment date, the requirement for post-attainment year
budgets will no longer apply in the area for the 1997 24-hour
PM2.5 NAAQS.
As noted above, the State included a trading mechanism to be used
in transportation conformity analyses that would be used in conjunction
with the budgets in the 2018 PM2.5 Plan, as allowed for
under 40 CFR 93.124(b). This trading mechanism would allow future
decreases in NOX emissions from on-road mobile sources to
offset any on-road increases in PM2.5, using a 2 to 1
NOX to PM2.5 ratio for the 1997 24-hour
PM2.5 NAAQS. To ensure that the trading mechanism does not
affect the ability to meet the NOX budget, the Plan provides
that the NOX emissions reductions available to supplement
the PM2.5 budget would only be those remaining after the
NOX budget has been met. The San Joaquin Valley MPOs will
have to document clearly the calculations used in the trading when
demonstrating conformity, along with any additional reductions of
NOX and PM2.5 emissions in the conformity
analysis. The trading calculations must be performed prior to the final
rounding to demonstrate conformity with the budgets.
The EPA has reviewed the trading mechanism as described on pages D-
125 to D-127 in Appendix D of the 2018 PM2.5 Plan and finds
it is appropriate for transportation conformity purposes in the San
Joaquin Valley for the 1997 24-hour PM2.5 NAAQS. The
methodology for estimating the trading ratio for conformity purposes is
essentially an update (based on newer modeling) of the approach that
the EPA previously approved for the 2008 PM2.5 Plan for the
1997 PM2.5 NAAQS \259\ and the 2012 PM2.5 Plan
for the 2006 24-hour PM2.5 NAAQS.\260\ The State's approach
in the previous plans was to model the ambient PM2.5 effect
of areawide NOX emissions reductions and of areawide direct
PM2.5 emissions reductions, and to express the ratio of
these modeled sensitivities as an inter-pollutant trading ratio.
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\259\ 80 FR 1816, 1841 (January 13, 2015) (noting the EPA's
prior approval of MVEBs for the 1997 annual and 24-hour
PM2.5 standards in the 2008 PM2.5 Plan at 76
FR 69896).
\260\ 81 FR 59876 (August 31, 2016).
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In the updated analysis for the 2018 PM2.5 plan, the
State completed separate sensitivity analyses for the annual and 24-
hour NAAQS and modeled only transportation related sources in the
nonattainment area. The ratio the State is proposing to use for
transportation conformity purposes is derived from air quality modeling
that evaluated the effect of reductions in transportation-related
NOX and PM2.5 emissions in the San Joaquin Valley
on ambient concentrations at the Bakersfield-California Avenue,
Bakersfield-Planz, Fresno-Garland, and Fresno-Hamilton & Winery
monitoring sites. The modeling that the State performed to evaluate the
effectiveness of NOX and PM2.5 reductions on
ambient 24-hour concentrations showed NOX to
PM2.5 ratios that range from a high of 2.3 at the
Bakersfield-California Avenue monitor to a low of 1.6 at the Fresno-
Hamilton & Winery monitor.\261\ In our July 22, 2020 action on the 2018
PM2.5 Plan for the 2006 PM2.5 NAAQS, we found
that the State's approach is a reasonable method to use to develop
ratios for transportation conformity purposes and approved the 2 to 1
NOX to PM2.5 trading mechanism as an enforceable
component of the transportation conformity program for the San Joaquin
Valley for the 2006 PM2.5 NAAQS.\262\ Here, we similarly
find that the State's approach is reasonable and propose to
[[Page 53179]]
approve the 2 to 1 NOX to PM2.5 trading ratio.
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\261\ 2018 PM2.5 Plan, Appendix D, D-126.
\262\ 85 FR 44192.
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If approved, this trading ratio will replace the 9 to 1
NOX to PM2.5 trading ratio approved for the San
Joaquin Valley for analysis years after 2014 for the 1997 24-hour
PM2.5 NAAQS.\263\
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\263\ 76 FR 69896.
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Under the transportation conformity rule, once budgets are
approved, they cannot be superseded by revised budgets submitted for
the same CAA purpose and the same year(s) addressed by the previously
approved SIP until the EPA approves the revised budgets as a SIP
revision. In other words, as a general matter, such approved budgets
cannot be superseded by revised budgets found adequate, but rather only
through approval of the revised budgets, unless the EPA specifies
otherwise in its approval of a SIP by limiting the duration of the
approval to last only until subsequently submitted budgets are found
adequate.\264\
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\264\ 40 CFR 93.118(e)(1).
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In the submittal letter for the 2018 PM2.5 Plan, CARB
requested that we limit the duration of our approval of the budgets to
the period before the effective date of the EPA's adequacy finding for
any subsequently submitted budgets.\265\ The transportation conformity
rule allows us to limit the approval of budgets.\266\ However, we will
consider a state's request to limit an approval of its budgets only if
the request includes the following elements: \267\
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\265\ Letter dated May 9, 2019, from Richard W. Corey, Executive
Officer, CARB, to Mike Stoker, Regional Administrator, EPA Region 9,
3.
\266\ 40 CFR 93.118(e)(1).
\267\ 67 FR 69139 (November 15, 2002), limiting our prior
approval of MVEBs in certain California SIPs.
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(1) An acknowledgement and explanation as to why the budgets under
consideration have become outdated or deficient;
(2) A commitment to update the budgets as part of a comprehensive
SIP update; and
(3) A request that the EPA limit the duration of its approval to
the period before new budgets have been found to be adequate for
transportation conformity purposes.
CARB's request includes an explanation for why the budgets have
become, or will become, outdated or deficient. In short, CARB has
requested that we limit the duration of the approval of the budgets in
light of the EPA's approval of EMFAC2017, an updated version of the
model (EMFAC2014) used for the budgets in the SJV PM2.5
Plan.\268\ EMFAC2017 updates vehicle mix and emissions data of the
previously approved version of the model, EMFAC2014.
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\268\ On August 15, 2019, the EPA approved and announced the
availability of EMFAC2017, the latest update to the EMFAC model for
use by the State and local governments to meet CAA requirements. 84
FR 41717.
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In light of the EPA's approval of EMFAC2017, CARB explains that the
budgets in the SJV PM2.5 Plan, which we are proposing to
approve in today's action, will become outdated and will need to be
revised using EMFAC2017. In addition, CARB states that, without the
ability to replace the budgets using the budget adequacy process, the
benefits of using the updated data may not be realized for a year or
more after the updated SIP (with the EMFAC2017-derived budgets) is
submitted, due to the length of the SIP approval process. We find that
CARB's explanation for limiting the duration of the approval of the
budgets is appropriate and provides us with a reasonable basis for
limiting the duration of the approval of the budgets.
We note that CARB has not committed to update the budgets as part
of a comprehensive SIP update, but as a practical matter, CARB must
submit a SIP revision that includes updated demonstrations as well as
the updated budgets to meet the adequacy criteria in 40 CFR
93.118(e)(4).\269\ Therefore, we do not need a specific commitment for
such a plan at this time. For the reasons provided above, and in light
of CARB's explanation for why the budgets will become outdated and
should be replaced upon an adequacy finding for updated budgets, we
propose to limit the duration of our approval of the budgets addressed
in this action to the period before we find revised budgets based on
EMFAC2017 to be adequate.
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\269\ Under 40 CFR 93.118(e)(4), the EPA will not find a budget
in a submitted SIP to be adequate unless, among other criteria, the
budgets, when considered together with all other emissions sources,
are consistent with applicable requirements for RFP and attainment.
40 CFR 93.118(e)(4)(iv).
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H. Nonattainment New Source Review Requirements Under CAA Section
189(e)
CAA section 189(e) specifically requires that the control
requirements applicable to major stationary sources of direct
PM2.5 also apply to major stationary sources of
PM2.5 precursors, except where the Administrator determines
that such sources do not contribute significantly to PM2.5
levels that exceed the NAAQS in the area.\270\ The control requirements
applicable to major stationary sources of direct PM2.5 in a
Serious PM2.5 nonattainment area include, at minimum, the
requirements of a nonattainment NSR permit program meeting the
requirements of CAA sections 172(c)(5) and 189(b)(3). As part of our
April 7, 2015 final action to reclassify the San Joaquin Valley area as
Serious nonattainment for the 1997 PM2.5 standards, we
established a May 7, 2016 deadline for the State to submit
nonattainment NSR SIP revisions addressing the requirements of CAA
sections 189(b)(3) and 189(e) of the Act for the 1997 PM2.5
NAAQS.\271\
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\270\ General Preamble, 13539 and 13541-13542.
\271\ 80 FR 18528, 18533.
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California submitted nonattainment NSR SIP revisions to address the
subpart 4 requirements for the San Joaquin Valley Serious
PM2.5 nonattainment area on November 20, 2019.\272\ We are
not proposing any action on this submission at this time. We will act
on this submission through a separate rulemaking, as appropriate.
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\272\ Letter dated November 15, 2019, from Richard W. Corey,
Executive Officer, CARB, to Michael Stoker, Regional Administrator,
EPA Region IX.
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V. Determination of Attainment by the Attainment Date
A. Requirements for Attainment Determinations
Sections 179(c)(1) and 188(b)(2) of the CAA require the EPA to
determine whether a state with a PM2.5 nonattainment area
attained the applicable PM2.5 NAAQS by the applicable
attainment date, based on the area's air quality as of the attainment
date. A determination of whether an area's air quality currently meets
the PM2.5 NAAQS is generally based upon the most recent
three years of complete, quality-assured data gathered at established
State and Local Air Monitoring Stations (SLAMS) in a nonattainment area
and entered into the EPA's Air Quality System (AQS) database. Data from
ambient air monitors operated by state/local agencies in compliance
with the EPA monitoring requirements must be submitted to AQS.
Monitoring agencies annually certify that these data are accurate to
the best of their knowledge. Accordingly, the EPA relies primarily on
data in AQS when determining the attainment status of areas.\273\ The
EPA reviews all data to determine the area's air quality status in
accordance with 40 CFR part 50, Appendix N.
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\273\ See 40 CFR 50.7; 40 CFR part 50, Appendix L; 40 CFR part
53; 40 CFR part 58, and 40 CFR part 58, appendices A, C, D, and E.
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Under EPA regulations in 40 CFR 50.7 and in accordance with
Appendix N, the 1997 24-hour PM2.5 NAAQS are met when the
design value is less than or equal to 65 [micro]g/m\3\ (based on the
rounding convention in 40 CFR part 50,
[[Page 53180]]
Appendix N) at each eligible monitoring site within the area. Data
completeness requirements for a given year are met when at least 75
percent of the scheduled sampling days for each quarter have valid
data.\274\
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\274\ 40 CFR part 50, Appendix N, section 4.2(b).
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B. Monitoring Network Considerations
Section 110(a)(2)(B)(i) of the CAA requires states to establish and
operate air monitoring networks to compile data on ambient air quality
for all criteria pollutants. The monitoring requirements are specified
in 40 CFR part 58. These requirements are applicable to state, and
where delegated, local air monitoring agencies that operate criteria
pollutant monitors. The regulations in 40 CFR part 58 establish
specific requirements for operating air quality surveillance networks
to measure ambient concentrations of PM2.5, including
requirements for measurement methods, network design, quality assurance
procedures, and in the case of large urban areas, the minimum number of
monitoring sites designated as SLAMS.
In section 4.7 of Appendix D to 40 CFR part 58, the EPA specifies
minimum monitoring requirements for PM2.5 to operate at
SLAMS. SLAMS produce data comparable to the NAAQS, and therefore, the
monitor must be an approved federal reference method (FRM), federal
equivalent method (FEM), or approved regional method (ARM). The minimum
number of SLAMS required is described in section 4.7.1 and can be met
by either filter-based or continuous FRMs or FEMs. The monitoring
regulations also provide that each core-based statistical area (CBSA)
must operate a minimum number of PM2.5 continuous monitors;
\275\ however, this requirement can be met by either an FEM or a non-
FEM continuous monitor, and the continuous monitors can be located with
other SLAMS or at a different location. Consequently, the monitoring
requirements for PM2.5 can be met with filter-based FRMs/
FEMs, continuous FEMs, continuous non-FEMs, or a combination of
monitors at each required SLAMS.
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\275\ 40 CFR part 58, Appendix D, section 4.7.2.
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Under 40 CFR 58.10, states are required to submit annual monitoring
network plans to the EPA.\276\ Within the San Joaquin Valley, CARB and
the District are the agencies responsible for assuring that the area
meets air quality monitoring requirements. CARB and SJVUAPCD submit
monitoring network plans to the EPA annually. These plans describe and
discuss the status of the air monitoring network, as required under 40
CFR 58.10. The EPA reviews these annual network plans for compliance
with the applicable reporting requirements in 40 CFR part 58. With
respect to PM2.5, we have found that the CARB and SJVUAPCD
annual network plans meet the applicable requirements under 40 CFR part
58.\277\
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\276\ 40 CFR 58.10(a)(1).
\277\ Letter dated November 5, 2018, from Gwen Yoshimura,
Manager, Air Quality Analysis Office, EPA Region IX, to Sheraz Gill,
Deputy Air Pollution Control Office, SJVUAPCD; letter dated November
6, 2019, from Gwen Yoshimura, Manager, Air Quality Analysis Office,
EPA Region IX, to Jon Klassen, Director of Strategies and
Incentives, SJVUAPCD; letter dated October 26, 2020, from Gwen
Yoshimura, Manager, Air Quality Analysis Office, EPA Region IX, to
Jon Klassen, Director of Strategies and Incentives, SJVUAPCD; letter
dated November 26, 2018, from Gwen Yoshimura, Manager, Air Quality
Analysis Office, EPA Region IX, to Ravi Ramalingam, Chief, Consumer
Products and Air Quality Assessment Branch, CARB; letter dated
November 26, 2019, from Gwen Yoshimura, Manager, Air Quality
Analysis Office, EPA Region IX, to Ravi Ramalingam, Chief, Consumer
Products and Air Quality Assessment Branch, CARB; and letter dated
November 5, 2020, from Gwen Yoshimura, Manager, Air Quality Analysis
Office, EPA Region IX, to Ravi Ramalingam, Chief, Consumer Products
and Air Quality Assessment Branch, CARB.
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During the 2018-2020 period, PM2.5 ambient concentration
data that are eligible for use in determining whether an area has
attained the PM2.5 NAAQS were collected at a total of 18
sites within the San Joaquin Valley: 5 sites in Fresno County; 3 sites
in Kern County; 2 sites each in Kings, Merced, San Joaquin, and
Stanislaus counties; and 1 site each in Madera and Tulare counties. The
District operates 12 of these sites while CARB operates 6 of these
sites. All of the sites are designated SLAMS for PM2.5.\278\
The primary monitors are FRMs at 5 of the 18 sites and beta attenuation
monitor FEMs at 13 of the 18 sites. Overall, the District's
PM2.5 monitoring network meets, and in several Metropolitan
Statistical Areas (MSAs) exceeds, the PM2.5 minimum
monitoring requirements for the San Joaquin Valley.
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\278\ There are a number of other PM2.5 monitoring
sites within the valley, including other sites operated by the
District, the National Park Service, and certain Indian tribes, but
the data collected from these sites are non-regulatory and not
eligible for use in determining whether the San Joaquin Valley has
attained the PM2.5 NAAQS.
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Based on our review of the PM2.5 monitoring network as
summarized above, we find that the monitoring network in the San
Joaquin Valley is adequate for the purpose of collecting ambient
PM2.5 concentration data for use in determining whether the
San Joaquin Valley attained the 1997 24-hour PM2.5 NAAQS by
the December 31, 2020 attainment date.
C. Data Considerations and Proposed Determination
Under 40 CFR 58.15, monitoring agencies must certify, on an annual
basis, that data collected at all SLAMS and at all FRM, FEM, and ARM
SPM stations meet the EPA's quality assurance requirements. In doing
so, monitoring agencies must certify that the previous year of ambient
concentration and quality assurance data are submitted to AQS and that
the ambient concentration data are accurate. CARB annually certifies
that the data the agency submits to AQS are quality assured, including
the data collected at monitoring sites in the San Joaquin Valley.\279\
SJVUAPCD does the same for data submitted to AQS from monitoring sites
operated by the District.\280\
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\279\ For example, see letter dated June 21, 2021, from Sylvia
Vanderspek, Chief, Air Quality Planning Branch, CARB, to Gwen
Yoshimura, Manager, Air Quality Analysis Office, EPA Region 9, with
enclosures, certifying calendar year 2020 ambient air quality data
and quality assurance data.
\280\ For example, see letter dated June 22, 2021, from Jessica
Olsen, Program Manager, SJVUAPCD, to Elizabeth Adams, Director, Air
and Radiation Division, EPA Region IX, with attachments, certifying
calendar year 2020 ambient air quality data and quality assurance
data.
---------------------------------------------------------------------------
As noted above, CAA sections 179(c)(1) and 188(b)(2) require the
EPA to determine whether a PM2.5 nonattainment area attained
the applicable PM2.5 NAAQS by the applicable attainment
date, based on the area's air quality as of the attainment date. The
SJV PM2.5 Plan includes a modeled demonstration of
attainment by December 31, 2020, for the 1997 24-hour PM2.5
NAAQS. Thus, the EPA's evaluation of whether the San Joaquin Valley
PM2.5 nonattainment area has attained the 1997 24-hour
PM2.5 NAAQS is based on our review of the monitoring data
recorded during the three years preceding the attainment date (2018-
2020). Our review also takes into account the adequacy of the
PM2.5 monitoring network in the nonattainment area and the
reliability of the data collected by the network as discussed in the
previous sections of this document.
With respect to data completeness, we determined that the data
collected by CARB and the District meet the quarterly completeness
criterion for all 12 quarters of the three-year period at most of the
PM2.5 monitoring sites in the San Joaquin Valley. More
specifically, among the 18 PM2.5 monitoring sites from which
regulatory data are available, the data from 5 of the sites did not
meet the 75 percent completeness criterion (for each quarter); however,
the data from all but 3 sites (Fresno-
[[Page 53181]]
Foundry (AQS ID: 06-019-2016), Manteca (AQS ID: 06-077-2010), and
Clovis-Villa (AQS ID: 06-019-5001)) are sufficient nonetheless to
produce a valid design value for the 1997 24-hour PM2.5
NAAQS pursuant to the rules governing design value validity in 40 CFR
part 50, Appendix N, section 4.2. We note that monitors with incomplete
data in one or more quarters may still produce valid design values if
the conditions for applying the EPA's data substitution test are
met.\281\ The Bakersfield-Airport (Planz) (AQS ID: 06-029-0016) and
Hanford-Irwin (AQS ID: 06-031-1004) monitoring sites had incomplete
data in the 4th quarter and 3rd quarter of 2018, respectively; however,
both sites had between 50 and 75 percent data completeness for these
quarters and have valid design values after applying the maximum
quarterly value data substitution test.
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\281\ See 40 CFR part 50, Appendix N, section 4.2(b).
---------------------------------------------------------------------------
The Manteca monitoring site recorded data amounting to less than 75
percent completeness during the 1st, 2nd, and 3rd quarters of 2019 (61
percent, 66 percent, and 67 percent, respectively) due to ongoing
instrument operational issues. Under Appendix N, section 4.2(b) data
shall be considered valid, in spite of quarters with incomplete data,
if the resulting annual 98th percentile value or resulting 24-hour
NAAQS design value exceeds the standard. Here, the incomplete annual
98th percentile value, 26.8 [micro]g/m\3\, is well below the standard,
and the resulting design value for the site, 59 [micro]g/m\3\, is also
below the standard. Therefore, this provision of section 4.2(b) does
not validate the 2019 Manteca monitoring site data. Like Bakersfield-
Airport (Planz) and Hanford-Irwin, the data for the Manteca site
qualify for the maximum quarterly value data substitution test under 40
CFR part 50, Appendix N, section 4.2(c). However, upon applying the
data substitution test to the Manteca monitoring site data, we find
that the data do not pass the test (i.e., after substituting the
highest reported daily maximum PM2.5 value for a quarter for
all missing daily data in the matching deficient quarter, the resulting
test design value was above the 1997 24-hour PM2.5 NAAQS).
Because the data substitution test results in a test design value above
the NAAQS, the Manteca monitoring site 2019 design value is considered
invalid. The EPA then reviewed additional information about the
monitoring network and air quality data, including historical 24-hour
PM2.5 design value trends, to assess if the data collection
deficiency, in the context of data that otherwise show attainment,
precludes the EPA from determining that the San Joaquin Valley area
attained the 1997 24-hour PM2.5 NAAQS during the 2018-2020
period.
First, although the 2019 data were incomplete, the available data
that were collected over a substantial amount of the year show zero
exceedances of the NAAQS.
Second, the Manteca monitoring site has not historically been the
24-hour PM2.5 design value site for the San Joaquin Valley
area. For example, the Bakersfield-California (AQS ID: 06-029-0014)
monitoring site was the design value site for the 24-hour
PM2.5 NAAQS for 2011 to 2013, the Bakersfield-Airport
(Planz) monitoring site was the design value site in 2014, the
Corcoran-Patterson (AQS ID: 06-031-0004) monitoring site was the design
value site from 2015 to 2019, and the Modesto-14th Street (AQS ID: 06-
099-0005) monitoring site was the design value site in 2020.
Third, an assessment of long-term trends at the Manteca monitoring
site and nearby monitoring sites shows nearby sites have design values
below the 24-hour PM2.5 NAAQS and the Manteca site typically
has lower design values compared to nearby sites. For example, during
the 2013 to 2020 period, the Manteca monitoring site had consistently
lower design values for the 24-hour PM2.5 NAAQS than the
Stockton-Hazelton (AQS ID: 06-077-1002) and Modesto-14th Street
monitoring sites, which are located approximately 11 miles and 18
miles, respectively, from the Manteca monitoring site. The Stockton-
Hazelton and Modesto-14th Street monitoring sites have complete annual
24-hour design values that are below the 1997 24-hour PM2.5
NAAQS (after excluding monitored exceedances associated with the August
20-24, 2020 wildfire exceptional event, as discussed below) and provide
an appropriate comparison and characterization of air quality for the
areas surrounding the Manteca monitoring site. Thus, because the data
that were collected provide a 98th percentile value below the standard,
and the Manteca monitoring site has historically lower design value
concentrations relative to the 24-hour PM2.5 NAAQS and
design values at nearby locations, we find that the incomplete data
should not preclude the EPA from determining that the San Joaquin
Valley area has attained the 1997 24-hour PM2.5 NAAQS.
The remaining two sites, Fresno-Foundry and Clovis-Villa, recorded
data amounting to less than 50 percent completeness during multiple
quarters during the 2018-2020 period. Specifically, the Fresno-Foundry
monitoring site recorded less than 50 percent data capture during all
four quarters of 2018 and 2019 and the Clovis-Villa monitoring site
recorded less than 50 percent data capture during the 2nd and 4th
quarters of 2019. Thus, the data in these quarters are not eligible for
the maximum quarterly value data substitution test under the provisions
in 40 CFR part 50 Appendix N, section 4.2(c)(i), which state that if
any quarter has less than 50 percent data capture, then the required
test conditions are not met and the substitution test cannot be used.
Additionally, the data collected at these sites did not result in an
98th percentile value or resulting 24-hour NAAQS design value that
exceeds the standard under the provision of Appendix N section 4.2(b).
Therefore, the design values at these two sites are considered invalid.
However, the EPA reviewed historical 24-hour PM2.5 design
value trends and the causes of the incomplete data in the context of
data that otherwise show attainment, and found that the data collection
deficiency should not preclude a determination that the San Joaquin
Valley area attained the 1997 24-hour PM2.5 NAAQS during the
2018-2020 period.
The Fresno-Foundry monitoring site began operation on January 1,
2020. Although data completeness was 98 percent for year 2020, the data
completeness requirements for the 2018-2020 period are not met since
the site was not yet operational and thus data were not collected in
2018 and 2019. Because the incomplete data at the Fresno-Foundry
monitoring site is due to the site having only begun operation in 2020,
the incomplete data should not preclude the EPA from determining
whether the area has attained the NAAQS. Upon excluding monitored
exceedances associated with the August 20-24, 2020 wildfire exceptional
event, as discussed below, the Fresno-Foundry monitoring site has an
incomplete 2020 design value of 64 [micro]g/m\3\, which is below the
level of the 1997 24-hour PM2.5 NAAQS.
The Clovis-Villa monitoring site recorded less than 75 percent data
capture during the 2nd, 3rd, and 4th quarters of 2019 (48 percent, 66
percent, and 41 percent, respectively) due to ongoing instrument
operational issues. Because the data substitution test under 40 CFR
part 50, Appendix N, section 4.2(c) requires each quarter to have data
completeness of at least 50 percent, the Clovis-Villa 2019 data do not
qualify for the data substitution test. Like Manteca, the Clovis-Villa
site has not historically
[[Page 53182]]
been the 24-hour PM2.5 design value site. An assessment of
long-term trends at the Clovis-Villa monitoring site and a nearby
monitoring site shows that the Clovis-Villa site has historically had
design values below the 24-hour PM2.5 NAAQS and has had
lower design values compared to the nearby site. During the 2011 to
2019 period, the Clovis-Villa monitoring site consistently had lower
design values for the 24-hour PM2.5 NAAQS than the Fresno-
Garland monitoring site, which is located approximately four miles from
Clovis-Villa.\282\ The Fresno-Garland site has a complete 2020 annual
24-hour design value below the 1997 24-hour PM2.5 NAAQS and
provides an appropriate comparison and characterization of air quality
for the area surrounding the Clovis-Villa monitoring site. Furthermore,
the District exceeds the PM2.5 minimum monitoring
requirements for three PM2.5 SLAMs monitors in the Fresno
MSA as they are currently operating five SLAMs monitors.
---------------------------------------------------------------------------
\282\ The Clovis-Villa and Fresno-Garland monitoring sites have
the same 2020 design value of 62 [micro]g/m\3\.
---------------------------------------------------------------------------
Thus, based on the historical design value concentrations at the
Clovis-Villa monitoring site relative to the 24-hour PM2.5
NAAQS and the nearest site, we find that the incomplete data at the
Clovis-Villa monitoring site should not preclude the EPA from
determining the San Joaquin Valley area has attained the 1997 24-hour
PM2.5 NAAQS.
Table 5 shows the 24-hour PM2.5 design values at each of
the 18 SLAMS monitoring sites within the San Joaquin Valley
nonattainment area for the most recent three-year period (2018-2020).
The data indicate that the San Joaquin Valley area likely experienced
higher than normal PM2.5 concentrations in 2018 and 2020 due
to wildfire impacts during the summer and fall months.\283\ Table 5
shows that 98th percentile concentrations at all 18 monitors in the San
Joaquin Valley area with data spanning 2018 to 2020 are significantly
higher in 2018 and 2020 relative to concentrations in 2019, again,
likely due to the wildfires in those years. Accordingly, the 2018-2020
design values in Table 5 may also be higher than normal at certain
monitoring sites due to potential wildfire impacts within the 2018-2020
data period. Nevertheless, the data show that the 24-hour design value
for the 2018-2020 period was equal to or less than 65 [micro]g/m\3\
(i.e., the level of the 1997 24-hour PM2.5 NAAQS) at all
monitors after excluding monitored exceedances specifically associated
with the August 20-24, 2020 wildfire exceptional event, as discussed
below. Therefore, we are proposing to determine, based on complete (or
otherwise not inconsistent, as described above), quality-assured, and
certified data for 2018-2020, that the San Joaquin Valley area has
attained the 1997 24-hour PM2.5 NAAQS, consistent with
attainment of the standard projected by the State in the SJV
PM2.5 Plan.
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\283\ EPA, 2020 Raw Data Report, AMP350, accessed July 13, 2021.
Table 5--2018-2020 24-Hour PM2.5 Design Values for the San Joaquin Valley Nonattainment Area
--------------------------------------------------------------------------------------------------------------------------------------------------------
98th percentile ([micro]g/m\3\) 2018-2020 24-hour
County General location AQS ID ---------------------------------------------------------------------- design values
site 2018 2019 2020 ([micro]g/m\3\)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Fresno.................. Fresno--Pacific.... 06-019-5025 65.5.................. 37.1................. 81.0................. 61.
Fresno--Garland.... 06-019-0011 63.5.................. 36.9................. 85.0................. 62.
Fresno--Foundry.... 06-019-2016 Inc................... Inc.................. 63.9................. 64 (Inv).\a\
Clovis--Villa...... 06-019-5001 57.0.................. 28.0 (Inc)........... 99.5................. 62 (Inv).\b\
Tranquillity....... 06-019-2009 51.4.................. 17.1................. 92.5................. 54.
Kern.................... Bakersfield--Airpor 06-029-0016 60.8.................. 46.7................. 57.1................. 55.
t (Planz).
Bakersfield--Califo 06-029-0014 69.2.................. 43.4................. 79.2................. 64.
rnia Ave.
Bakersfield--Golden 06-029-0010 60.9.................. 44.3................. 76.9................. 61.
State Highway.
Kings................... Corcoran--Patterson 06-031-0004 78.0.................. 45.1................. 69.0................. 64.
Hanford--Irwin..... 06-031-1004 78.2.................. 41.1................. 72.6................. 64.
Madera.................. Madera--Avenue 14.. 06-039-2010 50.2.................. 23.9................. 87.7................. 54.
Merced.................. Merced--M Street... 06-047-2510 52.7.................. 29.5................. 77.1................. 53.
Merced--Coffee..... 06-047-0003 56.0.................. 23.4................. 78.3................. 53.
San Joaquin............. Stockton--Hazelton. 06-077-1002 92.3.................. 32.9................. 65.9................. 64.
Manteca............ 06-077-2010 84.6 \c\.............. 26.8 (Inc)........... 66.9................. 59 (Inv).\d\
Stanislaus.............. Modesto--14th 06-099-0005 100.4................. 28.4................. 67.1................. 65.
Street.
Turlock............ 06-099-0006 88.6.................. 36.0................. 67.7................. 64.
Tulare.................. Visalia............ 06-107-2002 63.4.................. 45.5................. 83.4................. 64.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Source: EPA, 2020 AQS Design Value Report, AMP480, accessed September 1, 2021.The Design Value Report excludes measurements with regionally concurred
exceptional event flags. AQS reports for 24-hour PM2.5 data are only available for the 2006 24-hour PM2.5 NAAQS as a Pollutant Standard, thus this
report only reflects the 2006 24-hour PM2.5 NAAQS and does not include the 1997 24-hour PM2.5 NAAQS as a Pollutant Standard. Subsequently, AQS only
allows the EPA to place concurrence flags on data associated with the 2006 24-hour PM2.5 NAAQS. 40 CFR part 50 Appendix N specifies the data handling
and design value calculations for both the 2006 24-hour PM2.5 NAAQS and the 1997 24-hour PM2.5 NAAQS. The design values in the Design Value Report for
the 2006 24-hr PM2.5 NAAQS for the San Joaquin Valley nonattainment area are the same as would be expected for the 1997 24-hr PM2.5 NAAQS if the
exceptional events for that NAAQS were correctly represented in AQS.
Notes: Inc = Incomplete data. Inv = Invalid design value due to incomplete data.
\a\ The 2018-2020 design value at Fresno-Foundry (AQS ID: 06-019-2016) is based on concentration data from January 1, 2020 to December 31, 2020. The
site began operation in 2020; therefore, data from January 1, 2018 to December 31, 2019 are not available. Based on 40 CFR part 50, Appendix N,
section 4.2(b), three years of valid annual PM2.5 98th percentile mass concentrations are required to produce a valid 24-hour PM2.5 NAAQS design
value. Thus, the Fresno-Foundry 2018-2020 design value is considered invalid.
\b\ Based on the design value calculation methodologies described in 40 CFR part 50, Appendix N, section 4.2(b), the Clovis-Villa (AQS ID: 06-019-5001)
2018-2020 design value is considered invalid due to incomplete data in the 2nd, 3rd, and 4th quarters of 2019.
[[Page 53183]]
\c\ Identification of the 98th percentile 24-hour concentration is based on the number of creditable samples in a given year. See 40 CFR part 50,
appendix N, section 4.5. Specifically, in any year for which there are at least 351 creditable samples, the 98th percentile is the 8th highest
concentration, and as the number of creditable samples decreases the 98th percentile concentration is represented by a data point closer to the
maximum concentration. The number of creditable samples in 2018 for Manteca is reflected inaccurately in AQS and results in an inaccurate 2018 98th
percentile concentration and 2018-2020 design value. Table 5 reflects the 2018 98th percentile concentration and 2018-2020 design value based on the
corrected number of creditable samples. See memorandum dated August 6, 2021, from Dena Vallano, EPA Region IX, to Docket EPA-R09-OAR-2021-0261,
Subject: ``San Joaquin Valley, CA 1997 24-hour PM2.5 Nonattainment Area, Manteca Monitoring.''
\d\ Based on the design calculation methodologies described in 40 CFR part 50, Appendix N, section 4.2(b), the Manteca (AQS ID: 06-077-2010) 2018-2020
design value is considered invalid due to incomplete data in the 1st, 2nd, and 3rd quarters of 2019.
In the EPA's review of monitoring data for the 1997 24-hour
PM2.5 NAAQS for the San Joaquin Valley nonattainment area,
the EPA is excluding certain exceedances of the standard from the
attainment determination presented herein because they were the result
of exceptional events. Under the EPA's Exceptional Events Rule
(EER),\284\ exceedances flagged as exceptional events will only be
considered for EPA concurrence if the data affect one of the types of
regulatory actions specified by the EER. The State has submitted a
demonstration for a wildfire PM2.5 exceptional event
covering a total of 30 measured exceedances occurring over 5
consecutive days (August 20-24, 2020) at 8 monitoring sites within the
San Joaquin Valley nonattainment area that were critical for informing
this attainment determination.\285\ The State's submission notes that
additional San Joaquin Valley monitoring sites were affected by
wildfire smoke during the 2018-2020 period, but that those dates were
not included in the submission because they did not cause the 2020
design values to violate the 1997 24-hour PM2.5 NAAQS and
did not have regulatory significance relevant to this
determination.\286\ The EPA reviewed the documentation that the State
provided to demonstrate that these exceedances meet the criteria for
exceptional events under the EER. The EPA concurred with the State's
determinations that, based on the weight of evidence, the exceedances
were caused by an exceptional event.\287\ Accordingly, the EPA has
determined that the monitored exceedances associated with this
exceptional event should not be used for regulatory purposes, including
the evaluation of whether the San Joaquin Valley nonattainment area has
attained by the attainment date and evaluation of the CAA Serious area
and section 189(d) plan submission. Excluding these exceedances caused
by uncontrollable emissions, the EPA proposes to determine that the San
Joaquin Valley has attained the 1997 24-hour PM2.5 NAAQS,
consistent with attainment of the standard projected by the State in
the SJV PM2.5 Plan.
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\284\ 40 CFR 50.1(j), (k), (l); 50.14(a)(1)(i); 51.930.
\285\ The eight monitoring sites covered by the August 20-24,
2020 wildfire exceptional event demonstration include Fresno-
Foundry, Bakersfield-Airport (Planz), Corcoran-Patterson, Hanford-
Irwin, Stockton-Hazelton, Manteca, Modesto-14th Street, and Turlock.
\286\ SJVUAPCD, ``Exceptional Event Demonstration for August
2020 PM2.5 Exceedances due to Wildfires'', May 11, 2021,
3.
\287\ Letter dated July 13, 2021, from Elizabeth J. Adams,
Director, Air and Radiation Division, EPA Region IX, to Michael
Benjamin, Division Chief, Air Quality Planning and Science Division,
CARB.
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VI. Summary of Proposed Action and Request for Public Comment
The EPA is proposing to determine that the San Joaquin Valley
nonattainment area has attained the 1997 24-hour PM2.5
NAAQS, based on complete (or otherwise not inconsistent), quality-
assured, and certified ambient air quality monitoring data for the
2018-2020 monitoring period. If finalized, this proposed determination
that the San Joaquin Valley nonattainment area has attained the 1997
24-hour PM2.5 NAAQS would not constitute a redesignation of
the area to attainment. Under CAA section 107(d)(3)(E), redesignations
of nonattainment areas to attainment require states to meet a number of
additional statutory criteria, including the EPA's approval of a SIP
revision demonstrating maintenance of the standard for 10 years after
redesignation. The designation status of the San Joaquin Valley area
will remain Serious nonattainment for the 1997 24-hour PM2.5
NAAQS until such time as the EPA determines that the area meets the CAA
requirements for redesignation to attainment.
For the reasons discussed in this proposed rule, under CAA section
110(k)(3), the EPA is also proposing to approve in part and disapprove
in part portions of the SJV PM2.5 Plan submitted by
California that pertain to the 1997 24-hour PM2.5 NAAQS in
the San Joaquin Valley nonattainment area as follows:
(1) We are proposing to approve the following elements as meeting
the Serious nonattainment area planning requirements:
(a) The 2013 base year emissions inventories as meeting the
requirements of CAA section 172(c)(3) and 40 CFR 51.1008(b);
(b) the BACM/BACT demonstration as meeting the requirements of CAA
section 189(b)(1)(B) and 40 CFR 51.1010(a);
(c) the demonstration (including air quality modeling) that the
Plan provides for attainment as expeditiously as practicable as meeting
the requirements of CAA sections 179(d) and 189(b) and 40 CFR
51.1011(b);
(d) the RFP demonstration as meeting the requirements of CAA
sections 172(c)(2) and 171(1) and 40 CFR 51.1012; and
(e) the quantitative milestone demonstration as meeting the
requirements of CAA section 189(c) and 40 CFR 51.1013;
(2) We are proposing to approve the following elements as meeting
the CAA section 189(d) planning requirements:
(a) The 2013 base year emissions inventories as meeting the
requirements of CAA section 172(c)(3) and 40 CFR 51.1008(c);
(b) the BACM/BACT demonstration as meeting the requirements of CAA
sections 189(a)(1)(C) \288\ and 189(b)(1)(B) and 40 CFR 51.1010(c);
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\288\ As discussed in section III.B of this document, a section
189(d) plan must address any outstanding Moderate or Serious area
requirements that have not previously been approved. Because we have
not previously approved a subpart 4 RACM demonstration for the San
Joaquin Valley nonattainment area, we are also proposing to approve
the BACM/BACT demonstration in the SJV PM2.5 Plan as
meeting the subpart 4 RACM/RACT requirement for the area.
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(c) the demonstration that the Plan will, at a minimum, achieve an
annual five percent reduction in emissions of NOX as meeting
the requirements of CAA section 189(d) and 40 CFR 51.1010(c);
(d) the demonstration (including air quality modeling) that the
Plan provides for attainment as expeditiously as practicable as meeting
the requirements of CAA sections 179(d) and 189(d) and 40 CFR
51.1011(b);
(e) the RFP demonstration as meeting the requirements of CAA
sections 172(c)(2) and 171(1) and 40 CFR 51.1012; and
(f) the quantitative milestone demonstration as meeting the
requirements of CAA section 189(c) and 40 CFR 51.1013;
(3) We are proposing to approve the motor vehicle emission budgets
for 2017 and 2020 as shown in Table 8 of this proposed rule because
they are derived
[[Page 53184]]
from approvable RFP and attainment demonstrations and meet the
requirements of CAA section 176(c) and 40 CFR part 93, subpart A;
(4) We are proposing to approve the inter-pollutant trading
mechanism provided for use in transportation conformity analyses for
the 1997 24-hour PM2.5 NAAQS, in accordance with 40 CFR
93.124(b); and
(5) We are proposing to disapprove the contingency measure element
of the SJV PM2.5 Plan for the 1997 24-hour PM2.5
NAAQS for both the Serious area and CAA section 189(d) planning
requirements for failing to meet the requirements of CAA section
172(c)(9). However, based on our proposed finding of attainment by the
applicable attainment date, we are also proposing to determine that the
contingency measures requirement will no longer apply to the San
Joaquin Valley area for the 1997 24-hour PM2.5 NAAQS if we
finalize the determination of attainment by the applicable attainment
date. Therefore, our proposed disapproval, if finalized, would not
trigger sanctions or FIP clocks, and we are proposing to issue a
protective finding for transportation conformity determinations under
40 CFR 93.120(a)(3) if the proposed disapproval is finalized.
The EPA is soliciting public comments on the issues discussed in
this proposed rule. We will accept comments from the public on this
proposal for the next 30 days.
VII. Statutory and Executive Order Reviews
Additional information about these statutes and Executive Orders
can be found at https://www2.epa.gov/laws-regulations/laws-and-executive-orders.
A. Executive Order 12866: Regulatory Planning and Review and Executive
Order 13563: Improving Regulation and Regulatory Review
This action is not a significant regulatory action and was
therefore not submitted to the Office of Management and Budget (OMB)
for review.
B. Paperwork Reduction Act (PRA)
This action does not impose an information collection burden under
the PRA because the proposed partial SIP approval and partial
disapproval, if finalized, will not in-and-of itself create any new
information collection burdens but will simply disapprove certain State
requirements for inclusion in the SIP.
C. Regulatory Flexibility Act (RFA)
I certify that this action will not have a significant economic
impact on a substantial number of small entities under the RFA. This
action will not impose any requirements on small entities. This
proposed partial SIP approval and partial disapproval, if finalized,
will not in-and-of itself create any new requirements but will simply
disapprove certain state requirements for inclusion in the SIP.
D. Unfunded Mandates Reform Act (UMRA)
This action does not contain any unfunded mandate as described in
UMRA, 2 U.S.C. 1531-1538, and does not significantly or uniquely affect
small governments. This action proposes to partially approve and
partially disapprove pre-existing requirements under state or local law
and imposes no new requirements. Accordingly, no additional costs to
state, local, or tribal governments, or to the private sector, result
from this action.
E. Executive Order 13132: Federalism
This action does not have federalism implications. It will not have
substantial direct effects on the states, on the relationship between
the national government and the states, or on the distribution of power
and responsibilities among the various levels of government.
F. Executive Order 13175: Coordination With Indian Tribal Governments
This action does not have tribal implications, as specified in
Executive Order 13175, because the SIP revision that the EPA is
proposing to partially approve and partially disapprove would not apply
on any Indian reservation land or in any other area where the EPA or an
Indian tribe has demonstrated that a tribe has jurisdiction, and will
not impose substantial direct costs on tribal governments or preempt
tribal law. Thus, Executive Order 13175 does not apply to this action.
G. Executive Order 13045: Protection of Children From Environmental
Health Risks and Safety Risks
The EPA interprets Executive Order 13045 as applying only to those
regulatory actions that concern environmental health or safety risks
that the EPA has reason to believe may disproportionately affect
children, per the definition of ``covered regulatory action'' in
section 2-202 of the Executive Order. This action is not subject to
Executive Order 13045 because this proposed partial SIP approval and
partial disapproval, if finalized, will not in-and-of itself create any
new regulations but will simply disapprove certain state requirements
for inclusion in the SIP.
H. Executive Order 13211: Actions That Significantly Affect Energy
Supply, Distribution, or Use
This action is not subject to Executive Order 13211 because it is
not a significant regulatory action under Executive Order 12866.
I. National Technology Transfer and Advancement Act (NTTAA)
Section 12(d) of the NTTAA directs the EPA to use voluntary
consensus standards in its regulatory activities unless to do so would
be inconsistent with applicable law or otherwise impractical. The EPA
believes that this action is not subject to the requirements of section
12(d) of the NTTAA because application of those requirements would be
inconsistent with the CAA.
J. Executive Order 12898: Federal Actions To Address Environmental
Justice in Minority Populations and Low-Income Population
The EPA lacks the discretionary authority to address environmental
justice in this rulemaking.
List of Subjects in 40 CFR Part 51
Environmental protection, Air pollution control, Ammonia,
Incorporation by reference, Intergovernmental relations, Nitrogen
dioxide, Particulate matter, Reporting and recordkeeping requirements,
Sulfur dioxide, Volatile organic compounds.
Authority: 42 U.S.C. 7401 et seq.
Dated: September 17, 2021.
Deborah Jordan,
Acting Regional Administrator, Region IX.
[FR Doc. 2021-20613 Filed 9-23-21; 8:45 am]
BILLING CODE 6560-50-P
