Air Plan Disapproval; Kentucky; Interstate Transport Requirements for the 2015 8-Hour Ozone National Ambient Air Quality Standards, 9498-9516 [2022-02947]
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Federal Register / Vol. 87, No. 35 / Tuesday, February 22, 2022 / Proposed Rules
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the Administrator intends to exercise
the complete discretion afforded to him
under the CAA to make and publish a
finding that the final action (to the
extent a court finds the action to be
locally or regionally applicable) is based
on a determination of ‘‘nationwide
scope or effect’’ within the meaning of
CAA section 307(b)(1). Through this
rulemaking action (in conjunction with
a series of related actions on other SIP
submissions for the same CAA
obligations), the EPA interprets and
applies section 110(a)(2)(d)(i)(I) of the
CAA for the 2015 ozone NAAQS based
on a common core of nationwide policy
judgments and technical analysis
concerning the interstate transport of
pollutants throughout the continental
U.S. In particular, the EPA is applying
here (and in other proposed actions
related to the same obligations) the
same, nationally consistent 4-step
framework for assessing good neighbor
obligations for the 2015 ozone NAAQS.
The EPA relies on a single set of
updated, 2016-base year photochemical
grid modeling results of the year 2023
as the primary basis for its assessment
of air quality conditions and
contributions at Steps 1 and 2 of that
framework. Further, the EPA proposes
to determine and apply a set of
nationally consistent policy judgments
to apply the 4-step framework. The EPA
has selected a nationally uniform
analytic year (2023) for this analysis and
is applying a nationally uniform
approach to nonattainment and
maintenance receptors and a nationally
uniform approach to contribution
threshold analysis.61 For these reasons,
the Administrator intends, if this
proposed action is finalized, to exercise
the complete discretion afforded to him
under the CAA to make and publish a
finding that this action is based on one
or more determinations of nationwide
scope or effect for purposes of CAA
section 307(b)(1).62
61 A finding of nationwide scope or effect is also
appropriate for actions that cover states in multiple
judicial circuits. In the report on the 1977
Amendments that revised section 307(b)(1) of the
CAA, Congress noted that the Administrator’s
determination that the ‘‘nationwide scope or effect’’
exception applies would be appropriate for any
action that has a scope or effect beyond a single
judicial circuit. See H.R. Rep. No. 95–294 at 323,
324, reprinted in 1977 U.S.C.C.A.N. 1402–03.
62 The EPA may take a consolidated, single final
action on all the proposed SIP disapproval actions
with respect to obligations under CAA section
110(a)(2)(D)(i)(I) for the 2015 ozone NAAQS.
Should EPA take a single final action on all such
disapprovals, this action would be nationally
applicable, and the EPA would also anticipate, in
the alternative, making and publishing a finding
that such final action is based on a determination
of nationwide scope or effect.
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List of Subjects in 40 CFR Part 52
Environmental protection, Air
pollution control, Incorporation by
reference, Ozone.
Authority: 42 U.S.C. 7401 et seq.
Dated: January 31, 2022.
Lisa Garcia,
Regional Administrator, Region 2.
[FR Doc. 2022–02946 Filed 2–18–22; 8:45 am]
BILLING CODE 6560–50–P
ENVIRONMENTAL PROTECTION
AGENCY
40 CFR Part 52
[EPA–R04–OAR–2021–0841; EPA–HQ–
OAR–2021–0663; FRL–9423–01–R4]
Air Plan Disapproval; Kentucky;
Interstate Transport Requirements for
the 2015 8-Hour Ozone National
Ambient Air Quality Standards
Environmental Protection
Agency (EPA).
ACTION: Proposed rule.
AGENCY:
Pursuant to the Federal Clean
Air Act (CAA or the Act), the
Environmental Protection Agency (EPA
or Agency) is proposing to disapprove a
State Implementation Plan (SIP)
submittal from the Kentucky Energy and
Environment Cabinet, Department of
Environmental Quality (DAQ) (herein
after referred to as Kentucky or the
Commonwealth) regarding the interstate
transport requirements for the 2015 8hour ozone national ambient air quality
standards (NAAQS or standard). The
‘‘Good Neighbor’’ or ‘‘Interstate
Transport’’ provision requires that each
state’s implementation plan contain
adequate provisions to prohibit
emissions from within the state from
significantly contributing to
nonattainment or interfering with
maintenance of the NAAQS in other
states. This requirement is part of the
broader set of ‘‘infrastructure’’
requirements, which are designed to
ensure that the structural components of
each state’s air quality management
program are adequate to meet the state’s
responsibilities under the CAA. This
disapproval, if finalized, will establish a
2-year deadline for EPA to promulgate
a Federal Implementation Plan (FIP) to
address the relevant interstate transport
requirements, unless EPA approves a
subsequent SIP submittal that meets
these requirements. Disapproval does
not start a mandatory sanctions clock.
DATES: Comments must be received on
or before April 25, 2022.
Withdrawals: As of February 22, 2022,
the proposed rule published in
SUMMARY:
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December 30, 2019, at 84 FR 71854, is
withdrawn.
ADDRESSES: You may submit comments,
identified by Docket No. EPA–R04–
OAR–2021–0841, through the Federal
eRulemaking Portal at https://
www.regulations.gov following the
online instructions for submitting
comments.
Instructions: All submissions received
must include the Docket No. EPA–R04–
OAR–2021–0841 for this rulemaking.
Comments received may be posted
without change to https://
www.regulations.gov/, including any
personal information provided. For
detailed instructions on submitting
comments and additional information
on the rulemaking process, see the
‘‘Public Participation’’ heading of the
SUPPLEMENTARY INFORMATION section of
this document. Out of an abundance of
caution for members of the public and
staff, the EPA Docket Center and
Reading Room are open to the public by
appointment only to reduce the risk of
transmitting COVID–19. The Docket
Center staff also continues to provide
remote customer service via email,
phone, and webform. For further
information on EPA Docket Center
services and the current status, please
visit EPA online at https://
www.epa.gov/dockets.
FOR FURTHER INFORMATION CONTACT:
Evan Adams of the Air Regulatory
Management Section, Air Planning and
Implementation Branch, Air and
Radiation Division, U.S. Environmental
Protection Agency, Region 4, 61 Forsyth
Street SW, Atlanta, Georgia 30303–8960.
Mr. Adams can be reached by telephone
at (404) 562–9009, or via electronic mail
at adams.evan@epa.gov.
SUPPLEMENTARY INFORMATION: Public
Participation: Submit your comments,
identified by Docket No. EPA–R04–
OAR–2021–0841, at https://
www.regulations.gov. Once submitted,
comments cannot be edited or removed
from the docket. EPA may publish any
comment received to its public docket.
Do not submit to EPA’s docket at
https://www.regulations.gov any
information you consider to be
Confidential Business Information (CBI)
or other information whose disclosure is
restricted by statute. Multimedia
submissions (audio, video, etc.) 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. 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).
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Federal Register / Vol. 87, No. 35 / Tuesday, February 22, 2022 / Proposed Rules
There are two dockets supporting this
action, EPA–R04–OAR–2021–0841 and
EPA–HQ–OAR–2021–0663. Docket No.
EPA–R04–OAR–2021–0841 contains
information specific to Kentucky,
including this notice of proposed
rulemaking. Docket No. EPA–HQ–OAR–
2021–0663 contains additional
modeling files, emissions inventory
files, technical support documents, and
other relevant supporting
documentation regarding interstate
transport of emissions for the 2015 8hour ozone NAAQS which are being
used to support this action. All
comments regarding information in
either of these dockets are to be made
in Docket No. EPA–R04–OAR–2021–
0841. 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-epadockets. Due to public health concerns
related to COVID–19, the EPA Docket
Center and Reading Room are open to
the public by appointment only. The
Docket Center staff also continues to
provide remote customer service via
email, phone, and webform. For further
information and updates on EPA Docket
Center services, please visit EPA online
at https://www.epa.gov/dockets.
EPA continues to carefully and
continuously monitor information from
the Centers for Disease Control and
Prevention (CDC), local area health
departments, and Federal partners so
that EPA can respond rapidly as
conditions change regarding COVID–19.
The indices to Docket No. EPA–R04–
OAR–2021–0841 and Docket No. EPA–
HQ–OAR–2021–0663 are available
electronically at www.regulations.gov.
While all documents in each docket are
listed in their respective index, some
information may not be publicly
available due to docket file size
restrictions or content (e.g., CBI).
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Table of Contents
I. Background
A. Description of Statutory Background
B. Description of EPA’s Four Step
Interstate Transport Regulatory Process
C. Background on EPA’s Ozone Transport
Modeling Information
D. EPA’s Approach to Evaluating Interstate
Transport SIPs for the 2015 8-Hour
Ozone NAAQS
II. Summary of Kentucky’s 2015 8-Hour
Ozone Interstate Transport SIP
Submission
A. Information Related to Emission Trends
From Kentucky Sources
B. Information Related to Connecticut
Monitors Provided by Kentucky
C. Information Related to the Harford,
Maryland Monitor Provided by Kentucky
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D. Summary of Conclusions From
Kentucky
E. Summary of Midwest Ozone Group TSD
Appended to Kentucky’s Submittal
III. EPA’s Evaluation of Kentucky’s 2015 8Hour Ozone Interstate Transport SIP
Submission
A. Results of EPA’s Step 1 and Step 2
Modeling and Findings for Kentucky
B. Evaluation of Information Provided by
Kentucky Regarding Step 1
C. Evaluation of Information Provided by
Kentucky Regarding Step 2
D. Evaluation of Information Provided by
Kentucky Regarding Step 3
E. Evaluation of Information Provided by
Kentucky Regarding Step 4
F. Conclusion
IV. Proposed Action
V. Statutory and Executive Order Reviews
I. Background
The following provides background
for EPA’s proposed action related to the
interstate transport requirements for the
2015 8-hour ozone NAAQS for the
Commonwealth of Kentucky.
A. Description of Statutory Background
On October 1, 2015, EPA promulgated
a revision to the ozone NAAQS (2015 8hour ozone NAAQS), lowering the level
of both the primary and secondary
standards to 0.070 parts per million
(ppm).1 Section 110(a)(1) of the CAA
requires states to submit, within 3 years
after promulgation of a new or revised
standard, SIP submissions meeting the
applicable requirements of section
110(a)(2).2 One of these applicable
requirements is found in CAA section
110(a)(2)(D)(i)(I), otherwise known as
the ‘‘good neighbor’’ or ‘‘interstate
transport’’ provision, which generally
requires SIPs to contain adequate
provisions to prohibit in-state emissions
activities from having certain adverse
air quality effects on other states due to
interstate transport of pollution. There
are two so-called ‘‘prongs’’ within CAA
section 110(a)(2)(D)(i)(I). A SIP for a
new or revised NAAQS must contain
adequate provisions prohibiting any
source or other type of emissions
activity within the state from emitting
air pollutants in amounts that will
significantly contribute to
nonattainment of the NAAQS in another
state (prong 1) or interfere with
maintenance of the NAAQS in another
1 National Ambient Air Quality Standards for
Ozone, Final Rule, 80 FR 65292 (October 26, 2015).
Although the level of the standard is specified in
the units of ppm, ozone concentrations are also
described in parts per billion (ppb). For example,
0.070 ppm is equivalent to 70 ppb.
2 SIP revisions that are intended to meet the
applicable requirements of section 110(a)(1) and (2)
of the CAA are often referred to as infrastructure
SIPs and the applicable elements under section
110(a)(2) are referred to as infrastructure
requirements.
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state (prong 2). EPA and states must give
independent significance to prong 1 and
prong 2 when evaluating downwind air
quality problems under CAA section
110(a)(2)(D)(i)(I).3
B. Description of EPA’s Four Step
Interstate Transport Regulatory Process
EPA is using the 4-step interstate
transport framework (or 4-step
framework) to evaluate the states’
implementation plan submittals
addressing the interstate transport
provision for the 2015 8-hour ozone
NAAQS. EPA has addressed the
interstate transport requirements of
CAA section 110(a)(2)(D)(i)(I) with
respect to prior ozone NAAQS in
several regional regulatory actions,
including the Cross-State Air Pollution
Rule (CSAPR), which addressed
interstate transport with respect to the
1997 ozone NAAQS as well as the 1997
and 2006 fine particulate matter
standards,4 the Cross-State Air Pollution
Rule Update (CSAPR Update) 5 and the
Revised CSAPR Update, both of which
addressed the 2008 ozone NAAQS.6
Through the development and
implementation of the CSAPR
rulemakings and prior regional
rulemakings pursuant to the interstate
transport provision,7 EPA, working in
partnership with states, developed the
following 4-step interstate transport
framework to evaluate a state’s
obligations to eliminate interstate
transport emissions under the interstate
transport provision for the ozone
NAAQS: (1) Identify monitoring sites
that are projected to have problems
attaining and/or maintaining the
NAAQS (i.e., nonattainment and/or
maintenance receptors); (2) identify
3 See North Carolina v. EPA, 531 F.3d 896, 909–
11 (D.C. Cir. 2008).
4 See Federal Implementation Plans: Interstate
Transport of Fine Particulate Matter and Ozone and
Correction of SIP Approvals, 76 FR 48208 (August
8, 2011).
5 Cross-State Air Pollution Rule Update for the
2008 Ozone NAAQS, 81 FR 74504 (October 26,
2016).
6 In 2019, the United States Court of Appeals for
the District of Columbia Circuit (D.C. Circuit)
remanded the CSAPR Update to the extent it failed
to require upwind states to eliminate their
significant contribution by the next applicable
attainment date by which downwind states must
come into compliance with the NAAQS, as
established under CAA section 181(a). Wisconsin v.
EPA, 938 F.3d 303, 313 (D.C. Cir. 2019). The
Revised CSAPR Update for the 2008 Ozone
NAAQS, 86 FR 23054 (April 30, 2021), responded
to the remand of the CSAPR Update in Wisconsin
and the vacatur of a separate rule, the ‘‘CSAPR
Close-Out,’’ 83 FR 65878 (December 21, 2018), in
New York v. EPA, 781 F. App’x. 4 (D.C. Cir. 2019).
7 In addition to CSAPR rulemakings, other
regional rulemakings addressing ozone transport
include the ‘‘NOX SIP Call,’’ 63 FR 57356 (October
27, 1998), and the ‘‘Clean Air Interstate Rule’’
(CAIR), 70 FR 25162 (May 12, 2005).
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states that impact those air quality
problems in other (i.e., downwind)
states sufficiently such that the states
are considered ‘‘linked’’ and therefore
warrant further review and analysis; (3)
identify the emissions reductions
necessary (if any), applying a
multifactor analysis, to eliminate each
linked upwind state’s significant
contribution to nonattainment or
interference with maintenance of the
NAAQS at the locations identified in
Step 1; and (4) adopt permanent and
enforceable measures needed to achieve
those emissions reductions.
C. Background on EPA’s Ozone
Transport Modeling Information
In general, EPA has performed
nationwide air quality modeling to
project ozone design values which are
used in combination with measured
data to identify nonattainment and
maintenance receptors. To quantify the
contribution of emissions from specific
upwind states on 2023 ozone design
values for the identified downwind
nonattainment and maintenance
receptors, EPA performed nationwide,
state-level ozone source apportionment
modeling for 2023. The source
apportionment modeling provided
contributions to ozone at receptors from
precursor emissions of anthropogenic
nitrogen oxides (NOX) and volatile
organic compounds (VOCs) in
individual upwind states.
EPA has released several documents
containing projected design values,
contributions, and information relevant
to evaluating interstate transport with
respect to the 2015 8-hour ozone
NAAQS. First, on January 6, 2017, EPA
published a notice of data availability
(NODA) in which the Agency requested
comment on preliminary interstate
ozone transport data including projected
ozone design values and interstate
contributions for 2023 using a 2011 base
year platform.8 In the NODA, EPA used
the year 2023 as the analytic year for
this preliminary modeling because that
year aligns with the expected attainment
year for Moderate ozone nonattainment
areas for the 2015 8-hour ozone
NAAQS.9 On October 27, 2017, EPA
released a memorandum (October 2017
memorandum) containing updated
modeling data for 2023, which
incorporated changes made in response
to comments on the NODA, and noted
that the modeling may be useful for
states developing SIPs to address
8 See Notice of Availability of the Environmental
Protection Agency’s Preliminary Interstate Ozone
Transport Modeling Data for the 2015 8-hour Ozone
National Ambient Air Quality Standard (NAAQS),
82 FR 1733 (January 6, 2017).
9 See 82 FR 1733, 1735 (January 6, 2017).
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interstate transport obligations for the
2008 ozone NAAQS.10 On March 27,
2018, EPA issued a memorandum
(March 2018 memorandum) noting that
the same 2023 modeling data released in
the October 2017 memorandum could
also be useful for identifying potential
downwind air quality problems with
respect to the 2015 8-hour ozone
NAAQS at Step 1 of the 4-step interstate
transport framework.11 The March 2018
memorandum also included the then
newly available contribution modeling
data for 2023 to assist states in
evaluating their impact on potential
downwind air quality problems for the
2015 8-hour ozone NAAQS under Step
2 of the 4-step interstate transport
framework.12 EPA subsequently issued
two more memoranda in August and
October 2018, providing additional
information to states developing
interstate transport SIP submissions for
the 2015 8-hour ozone NAAQS
concerning, respectively, potential
contribution thresholds that may be
appropriate to apply in Step 2 of the 4step interstate transport framework, and
considerations for identifying
downwind areas that may have
problems maintaining the standard at
Step 1 of the 4-step interstate transport
framework.13
10 See Information on the Interstate Transport
State Implementation Plan Submissions for the
2008 Ozone National Ambient Air Quality
Standards under Clean Air Act Section
110(a)(2)(D)(i)(I), October 27, 2017 (‘‘October 2017
memorandum’’), available in Docket No. EPA–HQ–
OAR–2021–0663 or at https://www.epa.gov/
interstate-air-pollution-transport/interstate-airpollution-transport-memos-and-notices.
11 See Information on the Interstate Transport
State Implementation Plan Submissions for the
2015 Ozone National Ambient Air Quality
Standards under Clean Air Act Section
110(a)(2)(D)(i)(I), March 27, 2018 (‘‘March 2018
memorandum’’), available in Docket No. EPA–HQ–
OAR–2021–0663 or at https://www.epa.gov/
interstate-air-pollution-transport/interstate-airpollution-transport-memos-and-notices.
12 The March 2018 memorandum, however,
provided, ‘‘While the information in this
memorandum and the associated air quality
analysis data could be used to inform the
development of these SIPs, the information is not
a final determination regarding states’ obligations
under the good neighbor provision. Any such
determination would be made through notice-andcomment rulemaking.’’
13 See Analysis of Contribution Thresholds for
Use in Clean Air Act Section 110(a)(2)(D)(i)(I)
Interstate Transport State Implementation Plan
Submissions for the 2015 Ozone National Ambient
Air Quality Standards, August 31, 2018) (‘‘August
2018 memorandum’’), and Considerations for
Identifying Maintenance Receptors for Use in Clean
Air Act Section 110(a)(2)(D)(i)(I) Interstate
Transport State Implementation Plan Submissions
for the 2015 Ozone National Ambient Air Quality
Standards, October 19, 2018 (‘‘October 2018
memorandum’’), available in Docket No. EPA–HQ–
OAR–2021–0663 for this action or at https://
www.epa.gov/airmarkets/memo-and-supplementalinformation-regarding-interstate-transport-sips2015-ozone-naaqs.
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Since the release of the modeling data
shared in the March 2018
memorandum, EPA performed updated
modeling using a 2016-based emissions
modeling platform (i.e., 2016v1). This
emissions platform was developed
under the EPA/Multi-Jurisdictional
Organization (MJO)/state collaborative
project.14 This collaborative project was
a multi-year joint effort by EPA, MJOs,
and states to develop a new, more recent
emissions platform for use by EPA and
states in regulatory modeling as an
improvement over the dated 2011-based
platform that EPA had used to project
ozone design values and contribution
data provided in the 2017 and 2018
memoranda. EPA used the 2016v1
emissions to project ozone design values
and contributions for 2023. On October
30, 2020, in the Notice of Proposed
Rulemaking for the Revised CSAPR
Update, EPA released and accepted
public comment on 2023 modeling that
used the 2016v1 emissions platform.15
Although the Revised CSAPR Update
addressed transport for the 2008 ozone
NAAQS, the projected design values
and contributions from the 2016v1
platform are also useful for identifying
downwind ozone problems and linkages
with respect to the 2015 8-hour ozone
NAAQS.16
Following the Revised CSAPR Update
final rule, EPA made further updates to
the 2016 emissions platform to include
mobile emissions from EPA’s Motor
Vehicle Emission Simulator (MOVES)
model 17 and updated emissions
projections for electric generating units
(EGUs) that reflect the emissions
reductions from the Revised CSAPR
Update, recent information on plant
closures, and other sector trends. The
construct of the updated emissions
platform, 2016v2, is described in the
Preparation of Emissions Inventories for
the 2016v2 North American Emissions
Modeling Platform technical support
document (TSD) for this proposed rule
and is included in Docket No. EPA–HQ–
OAR–2021–0663. EPA performed air
quality modeling of the 2016v2
emissions using the most recent public
release version of the Comprehensive
Air Quality Modeling with Extensions
(CAMx) photochemical modeling,
14 The results of this modeling, as well as the
underlying modeling files, are included in Docket
No. EPA–HQ–OAR–2021–0663.
15 See 85 FR 68964, 68981 (October 30, 2020).
16 See the Air Quality Modeling Technical
Support Document for the Final Revised Cross-State
Air Pollution Rule Update, included in Docket No.
EPA–HQ–OAR–2021–0663.
17 Additional details and documentation related
to the MOVES3 model can be found at https://
www.epa.gov/moves/latest-version-motor-vehicleemission-simulator-moves.
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version 7.10.18 EPA proposes to
primarily rely on modeling based on the
updated and newly available 2016v2
emissions platform in evaluating these
submissions with respect to Steps 1 and
2 of the 4-step interstate transport
framework. By using the updated
modeling results, EPA is using the most
current and technically appropriate
information for this proposed
rulemaking. Section III of this notice
and the Air Quality Modeling TSD
included in Docket No. EPA–HQ–OAR–
2021–0663 for this proposal contain
additional detail on the modeling
performed using the 2016v2 emissions
modeling.
In this notice, EPA is accepting public
comment on this updated 2023
modeling, which uses the 2016v2
emissions platform. Details on the air
quality modeling and the methods for
projecting design values and
determining contributions in 2023 are
described in the Air Quality Modeling
TSD for 2015 8-hour Ozone NAAQS
Transport SIP Proposed Actions.
Comments on EPA’s air quality
modeling should be submitted in Docket
No. EPA–R04–OAR–2021–0841.
Comments are not being accepted in
Docket No. EPA–HQ–OAR–2021–0663.
States may have chosen to rely on the
results of EPA modeling and/or
alternative modeling performed by
states or Multi-Jurisdictional
Organizations (MJOs) to evaluate
downwind air quality problems and
contributions as part of their
submissions. In section III, EPA
evaluates how Kentucky used air quality
modeling information in its submission.
D. EPA’s Approach to Evaluating
Interstate Transport SIPs for the 2015 8Hour Ozone NAAQS
EPA proposes to apply a consistent
set of policy judgments across all states
for purposes of evaluating interstate
transport obligations and the
approvability of interstate transport SIP
submittals for the 2015 8-hour ozone
NAAQS. These policy judgments reflect
consistency with relevant case law and
past Agency practice as reflected in
CSAPR and related rulemakings.
Nationwide consistency in approach is
particularly important in the context of
interstate ozone transport, which is a
regional-scale pollution problem
involving many smaller contributors.
Effective policy solutions to the problem
of interstate ozone transport going back
to the NOX SIP Call have necessitated
the application of a uniform framework
of policy judgments in order to ensure
an ‘‘efficient and equitable’’ approach.
See EME Homer City Generation, LP v.
EPA, 572 U.S. 489, 519 (2014).
In the March, August, and October
2018 memoranda, EPA recognized that
states may be able to establish
alternative approaches to addressing
their interstate transport obligations for
the 2015 8-hour ozone NAAQS that vary
from a nationally uniform framework.
EPA emphasized in these memoranda,
however, that such alternative
approaches must be technically justified
and appropriate in light of the facts and
circumstances of each particular state’s
submittal. In general, EPA continues to
believe that deviation from a nationally
consistent approach to ozone transport
must be substantially justified and have
a well-documented technical basis that
is consistent with relevant case law.
Where states submitted SIPs that rely on
any such potential concepts as may
have been identified or suggested in the
past, EPA will evaluate whether the
state adequately justified the technical
and legal basis for doing so.
EPA notes that certain potential
concepts included in an attachment to
the March 2018 memorandum require
unique consideration, and these ideas
do not constitute Agency guidance with
respect to transport obligations for the
2015 8-hour ozone NAAQS. Attachment
A to the March 2018 memorandum
identified a ‘‘Preliminary List of
Potential Flexibilities’’ that could
potentially inform SIP development.19
However, EPA made clear in that
attachment that the list of ideas were
not suggestions endorsed by the Agency
but rather ‘‘comments provided in
various forums’’ on which EPA sought
‘‘feedback from interested
stakeholders.’’ 20 Further, Attachment A
stated, ‘‘EPA is not at this time making
any determination that the ideas
discussed below are consistent with the
requirements of the CAA, nor [is EPA]
specifically recommending that states
use these approaches.’’ 21 Attachment A
to the March 2018 memorandum,
therefore, does not constitute agency
guidance, but was intended to generate
further discussion around potential
approaches to addressing ozone
transport among interested stakeholders.
To the extent states sought to develop or
rely on these ideas in support of their
SIP submittals, EPA will thoroughly
review the technical and legal
justifications for doing so.
The remainder of this section
describes EPA’s proposed framework
with respect to analytic year, definition
19 March
18 Ramboll
Environment and Health, January
2021, www.camx.com.
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20 Id.
2018 memorandum, Attachment A.
at A–1.
21 Id.
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of nonattainment and maintenance
receptors, selection of contribution
threshold, and multifactor control
strategy assessment.
1. Selection of Analytic Year
In general, the states and EPA must
implement the interstate transport
provision in a manner ‘‘consistent with
the provisions of [title I of the CAA].’’
See CAA section 110(a)(2)(D)(i). This
requires, among other things, that these
obligations are addressed consistently
with the timeframes for downwind areas
to meet their CAA obligations. With
respect to ozone NAAQS, under CAA
section 181(a), this means obligations
must be addressed ‘‘as expeditiously as
practicable’’ and no later than the
schedule of attainment dates provided
in CAA section 181(a)(1).22 Several D.C.
Circuit court decisions address the issue
of the relevant analytic year for the
purposes of evaluating ozone transport
air-quality problems. On September 13,
2019, the D.C. Circuit issued a decision
in Wisconsin v. EPA, remanding the
CSAPR Update to the extent that it
failed to require upwind states to
eliminate their significant contribution
by the next applicable attainment date
by which downwind states must come
into compliance with the NAAQS, as
established under CAA section 181(a).
See 938 F.3d 303, 313.
On May 19, 2020, the D.C. Circuit
issued a decision in Maryland v. EPA
that cited the Wisconsin decision in
holding that EPA must assess the impact
of interstate transport on air quality at
the next downwind attainment date,
including Marginal area attainment
dates, in evaluating the basis for EPA’s
denial of a petition under CAA section
126(b). Maryland v. EPA, 958 F.3d 1185,
1203–04 (D.C. Cir. 2020). The court
noted that ‘‘section 126(b) incorporates
the Good Neighbor Provision,’’ and,
therefore, ‘‘EPA must find a violation [of
section 126] if an upwind source will
significantly contribute to downwind
nonattainment at the next downwind
attainment deadline. Therefore, the
agency must evaluate downwind air
quality at that deadline, not at some
later date.’’ Id. at 1204 (emphasis
added). EPA interprets the court’s
holding in Maryland as requiring the
states and the Agency, under the good
neighbor provision, to assess downwind
air quality as expeditiously as
practicable and no later than the next
22 For attainment dates for the 2015 8-hour ozone
NAAQS, refer to CAA section 181(a), 40 CFR
51.1303, and Additional Air Quality Designations
for the 2015 Ozone National Ambient Air Quality
Standards, 83 FR 25776 (June 4, 2018, effective
August 3, 2018).
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applicable attainment date,23 which is
now the Moderate area attainment date
under CAA section 181 for ozone
nonattainment. The Moderate area
attainment date for the 2015 8-hour
ozone NAAQS is August 3, 2024.24 EPA
believes that 2023 is now the
appropriate year for analysis of
interstate transport obligations for the
2015 8-hour ozone NAAQS, because the
2023 ozone season is the last relevant
ozone season during which achieved
emissions reductions in linked upwind
states could assist downwind states
with meeting the August 3, 2024,
Moderate area attainment date for the
2015 8-hour ozone NAAQS.
EPA recognizes that the attainment
date for nonattainment areas classified
as Marginal for the 2015 8-hour ozone
NAAQS was August 3, 2021. Under the
Maryland holding, any necessary
emissions reductions to satisfy interstate
transport obligations should have been
implemented by no later than this date.
At the time of the statutory deadline to
submit interstate transport SIPs (October
1, 2018), many states relied upon EPA
modeling of the year 2023, and no state
provided an alternative analysis using a
2021 analytic year (or the prior 2020
ozone season). However, EPA must act
on SIP submittals using the information
available at the time it takes such action.
In this circumstance, EPA does not
believe it would be appropriate to
evaluate states’ obligations under CAA
section 110(a)(2)(D)(i)(I) as of an
attainment date that is wholly in the
past, because the Agency interprets the
interstate transport provision as forward
looking. See 86 FR 23054, 23074; see
also Wisconsin, 938 F.3d at 322.
Consequently, in this proposal EPA will
use the analytical year of 2023 to
evaluate each state’s CAA section
110(a)(2)(D)(i)(I) SIP submission with
respect to the 2015 8-hour ozone
NAAQS.
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2. Step 1 of the 4-Step Interstate
Transport Framework
In Step 1, EPA identifies monitoring
sites that are projected to have problems
23 EPA notes that the court in Maryland did not
have occasion to evaluate circumstances in which
EPA may determine that an upwind linkage to a
downwind air quality problem exists at Steps 1 and
2 of the interstate transport framework by a
particular attainment date, but for reasons of
impossibility or profound uncertainty the Agency is
unable to mandate upwind pollution controls by
that date. See Wisconsin, 938 F.3d at 320. The D.C.
Circuit noted in Wisconsin that upon a sufficient
showing, these circumstances may warrant
flexibility in effectuating the purpose of the
interstate transport provision.
24 See CAA section 181(a); 40 CFR 51.1303;
Additional Air Quality Designations for the 2015
Ozone National Ambient Air Quality Standards, 83
FR 25776 (June 4, 2018, effective August 3, 2018).
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attaining and/or maintaining the
NAAQS in the 2023 analytic year.
Where EPA’s analysis shows that a site
does not fall under the definition of a
nonattainment or maintenance receptor,
that site is excluded from further
analysis under EPA’s 4-step interstate
transport framework. For sites that are
identified as a nonattainment or
maintenance receptor in 2023, EPA
proceeds to the next step of the 4-step
interstate transport framework by
identifying the upwind state’s
contribution to those receptors.
EPA’s approach to identifying ozone
nonattainment and maintenance
receptors in this action is consistent
with the approach used in previous
transport rulemakings. EPA’s approach
gives independent consideration to both
the ‘‘contribute significantly to
nonattainment’’ and the ‘‘interfere with
maintenance’’ prongs of CAA section
110(a)(2)(D)(i)(I), consistent with the
D.C. Circuit’s direction in North
Carolina v. EPA.25
For the purpose of this proposal, EPA
identifies nonattainment receptors as
those monitoring sites that are projected
to have average design values that
exceed the NAAQS and that are also
measuring nonattainment based on the
most recent monitored design values.
This approach is consistent with prior
transport rulemakings, such as the
CSAPR Update, where EPA defined
nonattainment receptors as those areas
that both currently measure
nonattainment and that EPA projects
will be in nonattainment in the future
analytic year (i.e., 2023).26
In addition, in this proposal, EPA
identifies a receptor to be a
‘‘maintenance’’ receptor for purposes of
defining interference with maintenance,
consistent with the method used in
CSAPR and upheld by the D.C. Circuit
in EME Homer City Generation, L.P. v.
EPA, 795 F.3d 118, 136 (D.C. Cir.
2015).27 Specifically, EPA identified
maintenance receptors as those
receptors that would have difficulty
maintaining the relevant NAAQS in a
scenario that takes into account
historical variability in air quality at
25 See North Carolina v. EPA, 531 F.3d 896, 910–
11 (D.C. Cir. 2008) (holding that EPA must give
‘‘independent significance’’ to each prong of CAA
section 110(a)(2)(D)(i)(I)).
26 See 81 FR 74504 (October 26, 2016). This same
concept, relying on both current monitoring data
and modeling to define nonattainment receptor,
was also applied in CAIR. See 70 FR at 25241,
25249 (January 14, 2005); see also North Carolina,
531 F.3d at 913–14 (affirming as reasonable EPA’s
approach to defining nonattainment in CAIR).
27 See 76 FR 48208 (August 8, 2011). The CSAPR
Update and Revised CSAPR Update also used this
approach. See 81 FR 74504 (October 26, 2016) and
86 FR 23054 (April 30, 2021).
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that receptor. The variability in air
quality was determined by evaluating
the ‘‘maximum’’ future design value at
each receptor based on a projection of
the maximum measured design value
over the relevant period. EPA interprets
the projected maximum future design
value to be a potential future air quality
outcome consistent with the
meteorology that yielded maximum
measured concentrations in the ambient
data set analyzed for that receptor (i.e.,
ozone conducive meteorology). EPA
also recognizes that previously
experienced meteorological conditions
(e.g., dominant wind direction,
temperatures, air mass patterns)
promoting ozone formation that led to
maximum concentrations in the
measured data may reoccur in the
future. The maximum design value
gives a reasonable projection of future
air quality at the receptor under a
scenario in which such conditions do,
in fact, reoccur. The projected
maximum design value is used to
identify upwind emissions that, under
those circumstances, could interfere
with the downwind area’s ability to
maintain the NAAQS.
Recognizing that nonattainment
receptors are also, by definition,
maintenance receptors, EPA often uses
the term ‘‘maintenance-only’’ to refer to
those receptors that are not
nonattainment receptors. Consistent
with the concepts for maintenance
receptors, as described above, EPA
identifies ‘‘maintenance-only’’ receptors
as those monitoring sites that have
projected average design values above
the level of the applicable NAAQS, but
that are not currently measuring
nonattainment based on the most recent
official design values. In addition, those
monitoring sites with projected average
design values below the NAAQS, but
with projected maximum design values
above the NAAQS are also identified as
‘‘maintenance-only’’ receptors, even if
they are currently measuring
nonattainment based on the most recent
official design values.
3. Step 2 of the 4-Step Interstate
Transport Framework
In Step 2, EPA quantifies the
contribution of each upwind state to
each receptor in the 2023 analytic year.
The contribution metric used in Step 2
is defined as the average impact from
each state to each receptor on the days
with the highest ozone concentrations at
the receptor based on the 2023
modeling. If a state’s contribution value
does not equal or exceed the threshold
of 1 percent of the NAAQS (i.e., 0.70
ppb for the 2015 8-hour ozone NAAQS),
the upwind state is not ‘‘linked’’ to a
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downwind air quality problem, and
EPA, therefore, concludes that the state
does not significantly contribute to
nonattainment or interfere with
maintenance of the NAAQS in the
downwind states. However, if a state’s
contribution equals or exceeds the 1
percent threshold, the state’s emissions
are further evaluated in Step 3,
considering both air quality and cost as
part of a multi-factor analysis, to
determine what, if any, emissions might
be deemed ‘‘significant’’ and, thus, must
be eliminated under CAA section
110(a)(2)(D)(i)(I).
EPA is proposing to rely in the first
instance on the 1 percent threshold for
the purpose of evaluating a state’s
contribution to nonattainment or
maintenance of the 2015 8-hour ozone
NAAQS (i.e., 0.70 ppb) at downwind
receptors. This is consistent with the
Step 2 approach that EPA applied in
CSAPR for the 1997 ozone NAAQS,
which has subsequently been applied in
the CSAPR Update when evaluating
interstate transport obligations for the
2008 ozone NAAQS. EPA continues to
find 1 percent to be an appropriate
threshold. For ozone, as EPA found in
the CAIR, CSAPR, and the CSAPR
Update, a portion of the nonattainment
problems from anthropogenic sources in
the U.S. result from the combined
impact of relatively small contributions
from many upwind states, along with
contributions from in-state sources and,
in some cases, substantially larger
contributions from a subset of particular
upwind states. EPA’s analysis shows
that much of the ozone transport
problem being analyzed in this
proposed rule is still the result of the
collective impacts of contributions from
many upwind states. Therefore,
application of a consistent contribution
threshold is necessary to identify those
upwind states that should have
responsibility for addressing their
contribution to the downwind
nonattainment and maintenance
problems to which they collectively
contribute. Continuing to use 1 percent
of the NAAQS as the screening metric
to evaluate collective contribution from
many upwind states also allows EPA
(and states) to apply a consistent
framework to evaluate interstate
emissions transport under the interstate
transport provision from one NAAQS to
the next. See 81 FR at 74518 (August 8,
2011); see also 86 FR at 23085 (April 30,
2021) (reviewing and explaining
rationale from CSAPR, 76 FR at 48237–
38 (August 8, 2011), for selection of 1
percent threshold).
EPA’s August 2018 memorandum
recognized that in certain
circumstances, a state may be able to
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establish that an alternative contribution
threshold of 1 ppb is justifiable. Where
a state relies on this alternative
threshold, and where that state
determined that it was not linked at
Step 2 using the alternative threshold,
EPA will evaluate whether the state
provided a technically sound
assessment of the appropriateness of
using this alternative threshold based on
the facts and circumstances underlying
its application in the particular SIP
submission.
4. Step 3 of the 4-Step Interstate
Transport Framework
Consistent with EPA’s longstanding
approach to eliminating significant
contribution or interference with
maintenance, at Step 3, states linked at
Steps 1 and 2 are generally expected to
prepare a multifactor assessment of
potential emissions controls. EPA’s
analysis at Step 3 in prior Federal
actions addressing interstate transport
requirements has primarily focused on
an evaluation of cost-effectiveness of
potential emissions controls (on a
marginal cost-per-ton basis), the total
emissions reductions that may be
achieved by requiring such controls (if
applied across all linked upwind states),
and an evaluation of the air quality
impacts such emissions reductions
would have on the downwind receptors
to which a state is linked; other factors
may potentially be relevant if
adequately supported. In general, where
EPA’s or alternative air quality and
contribution modeling establishes that a
state is linked at Steps 1 and 2, it will
be insufficient at Step 3 for a state
merely to point to its existing rules
requiring control measures as a basis for
approval. In general, the emissionsreducing effects of all existing emissions
control requirements are already
reflected in the air quality results of the
modeling for Steps 1 and 2. If the state
is shown to still be linked to one or
more downwind receptor(s), states must
provide a well-documented evaluation
determining whether their emissions
constitute significant contribution or
interference with maintenance by
evaluating additional available control
opportunities by preparing a multifactor
assessment. While EPA has not
prescribed a particular method for this
assessment, EPA expects states at a
minimum to present a sufficient
technical evaluation. This would
typically include information on
emissions sources, applicable control
technologies, emissions reductions,
costs, cost effectiveness, and downwind
air quality impacts of the estimated
reductions, before concluding that no
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additional emissions controls should be
required.28
5. Step 4 of the 4-Step Interstate
Transport Framework
At Step 4, states (or EPA) develop
permanent and federally enforceable
control strategies to achieve the
emissions reductions determined to be
necessary at Step 3 to eliminate
significant contribution to
nonattainment or interference with
maintenance of the NAAQS. For a state
linked at Steps 1 and 2 to rely on an
emissions control measure at Step 3 to
address its interstate transport
obligations, that measure must be
included in the state’s implementation
plan so that it is permanent and
federally enforceable. See CAA section
110(a)(2)(D) (‘‘Each such [SIP] shall . . .
contain adequate provisions. . . .’’).
See also CAA section 110(a)(2)(A);
Committee for a Better Arvin v. EPA,
786 F.3d 1169, 1175–76 (9th Cir. 2015)
(holding that measures relied on by a
state to meet CAA requirements must be
included in the SIP).
II. Summary of Kentucky’s 2015 8-Hour
Ozone Interstate Transport SIP
Submission
On January 11, 2019, Kentucky
submitted a SIP revision, a portion of
which addressed the CAA section
110(a)(2)(D)(i)(I) interstate transport
requirements for the 2015 8-hour ozone
NAAQS. The Commonwealth’s SIP
submission provided Kentucky’s
analysis of its impact to downwind
states and concluded that the
Commonwealth had met the
requirements of CAA section
l10(a)(2)(D)(i)(I) (i.e., prongs 1 and 2)
because Kentucky’s SIP contains
adequate provisions to prevent sources
and other types of emissions activities
within the Commonwealth from
significantly contributing to
nonattainment, or interfering with the
maintenance, of downwind states with
respect to the 2015 8-hour ozone
NAAQS.
The Commonwealth’s submission
relied on the results of EPA’s modeling
of the year 2023, contained in the March
2018 memorandum, to identify
downwind nonattainment and
28 As examples of general approaches for how
such an analysis could be conducted for their
sources, states could look to the CSAPR Update, 81
FR 74504, 74539–51; CSAPR, 76 FR 48208, 48246–
63; CAIR, 70 FR 25162, 25195–229; or the NOX SIP
Call, 63 FR 57356, 57399–405. See also Revised
CSAPR Update, 86 FR 23054, 23086–23116.
Consistently across these rulemakings, EPA has
developed emissions inventories, analyzed different
levels of control stringency at different cost
thresholds, and assessed resulting downwind air
quality improvements.
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maintenance receptors that may be
‘‘linked’’ to emissions from sources in
Kentucky (which correlates to Step 1 of
the 4-step framework).29 The March
2018 modeling indicates that the
Commonwealth was linked to four
nonattainment receptors and one
maintenance monitor above 1% of the
NAAQS. The largest impact from
Kentucky sources on any downwind
nonattainment receptor in the East was
projected to be 0.89 ppb at the Fairfield
County, Connecticut (ID: 90013007) site.
The other nonattainment receptors to
which Kentucky was linked are: a
second site in Fairfield County (ID:
90019003); Milwaukee, Wisconsin (ID:
550790085); and Sheboygan, Wisconsin
(ID: 551170006). The impact from
Kentucky sources on the one downwind
maintenance-only receptor to which it
was linked in that modeling was 1.52
ppb at the Harford County, Maryland
monitor (ID: 240251001).
The Commonwealth reviewed EPA’s
August 2018 memorandum as it related
to the use of a potential alternative
contribution threshold of 1 ppb and
agreed that use of a 1 ppb contribution
threshold is comparable to the amount
of collective contribution captured
using a threshold equivalent to 1
percent of the NAAQS. Based on the
March 2018 modeling and application
of a 1 ppb alternative contribution
threshold, the Commonwealth found
that it would not be linked as a
significant contributor to the four
nonattainment receptors in Connecticut
and Wisconsin (which correlates to
EPA’s Step 2), and therefore concluded
that no further controls were required to
address its contribution to those four
receptors. Thus, the Commonwealth
concluded that Kentucky’s SIP contains
adequate provisions to prevent sources
and other types of emissions activities
within the Commonwealth from
contributing significantly to
nonattainment in any other state (i.e.,
‘‘prong 1’’ of CAA section
l10(a)(2)(D)(i)(I)) for the 2015 8-hour
ozone NAAQS.
After application of the 1 ppb
contribution threshold, Kentucky
remained linked to the downwind
maintenance-only receptor at Harford
County, Maryland (ID: 240251001)
because the Commonwealth’s
contribution of 1.52 ppb to this receptor
was greater than the 1 ppb alternative
threshold. Kentucky’s SIP submission
asserted that the amount of NOX
emission reductions required for an
29 EPA notes that Kentucky’s SIP submission is
not organized around EPA’s 4-step framework for
assessing good neighbor obligations, but EPA
summarizes the submission using that framework
for clarity here.
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upwind state should not be the same for
a monitor that is already attaining the
NAAQS as they are for a nonattainment
monitor. The Commonwealth further
asserted that local controls should be
implemented before requiring upwind
states to control their sources. Thus,
Kentucky concluded that no further
reductions other than on-the-books and
on-the-way measures are required to
address the Commonwealth’s interstate
transport obligation to eliminate its
contribution to the Harford County,
Maryland maintenance receptor.
In addition, Kentucky provided
information intended to demonstrate
that Kentucky’s SIP contains adequate
provisions to prevent sources and other
types of emissions activities within the
Commonwealth from significantly
contributing to nonattainment, or
interfering with the maintenance, of
downwind states with respect to the
2015 8-hour ozone NAAQS, and thus,
no additional emissions reductions from
Kentucky are necessary. Specifically,
Kentucky listed existing state, SIPapproved regulations and Federal
programs for sources in the
Commonwealth that it concluded
address the requirements of CAA
110(a)(2)(D)(i)(I) for the 2015 8-hour
ozone NAAQS.30 Kentucky provided
more detailed analyses related to several
specific topics, which are summarized
in sections below.
The Commonwealth also included
documents attached as appendices to its
submittal. The March 2018
memorandum and the August 2018
memorandum were attached at
appendices A and B, respectively.31 As
Appendix C, the Commonwealth
appended several documents developed
and/or submitted by the Midwest Ozone
Group (a consortium of upwind
industries with emitting facilities).32
This included a modeling analysis
developed by Alpine Geophysics titled
30 See Kentucky’s January 11, 2019, SIP
submission, at pages 20 through 30 for the list of
state, SIP-approved regulations and Federal
programs identified by Kentucky.
31 See the following Appendices to Kentucky’s
January 11, 2019, submission: Appendix A—
Information on the Interstate Transport State
Implementation Plan Submissions for the 2015
Ozone National Ambient Air Quality Standards
under Clean Air Act Section 110(a)(2)(D)(i)(I),
March 27, 2018 (‘‘March 2018 memorandum’’);
Appendix B—Analysis of Contribution Thresholds
for Use in Clean Air Act Section 110(a)(2)(D)(i)(I)
Interstate Transport State Implementation Plan
Submissions for the 2015 Ozone National Ambient
Air Quality Standards, August 31, 2018; and
Appendix D—Public Hearing & Statement of
Consideration.
32 See Appendix C to Kentucky’s January 11,
2019, submission—Midwest Ozone Group
Technical Support Document: ‘‘Good Neighbor
Modeling Technical Support Document for 8-Hour
Ozone Implementation Plans.’’
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‘‘Good Neighbor Modeling Technical
Support Document for the 8-hour Ozone
State Implementation Plans,’’ dated June
2018 (Alpine TSD). The Alpine TSD
contains alternative modeling of 2023
performed by Alpine Geophysics
sponsored by MOG, as well as
additional policy suggestions that MOG
suggested states could consider in
developing good neighbor SIP
submissions (see section 9 of the Alpine
TSD).33 The Alpine TSD also appended
a separate set of MOG comments on
EPA’s March 2018 memorandum.34
These comments and Alpine’s modeling
analysis were further summarized in a
Microsoft PowerPoint Presentation
titled ‘‘MOG’s Preview of 2015 Ozone
NAAQS Good Neighbor SIPs.’’ EPA also
summarizes the materials developed by
MOG that the Commonwealth included
as Appendix C to its submittal, although
it is unclear that Kentucky intended to
rely on all aspects of these materials.
A. Information Related to Emission
Trends From Kentucky Sources
With respect to ozone precursors
emitted from Kentucky sources,
Kentucky focused its analysis on NOX
emissions, as it found that ozone is far
more sensitive to NOX emissions than
VOC emissions in the Southeastern
United States and that controlling NOX
emissions is a more effective strategy in
reducing ozone. Kentucky reviewed
NOX emissions trends in the
Commonwealth, comparing annual NOX
emissions from 2008 to 2016, finding
that NOX emissions in Kentucky have
significantly decreased since 2008. The
Commonwealth asserted that it has
significantly lowered NOX emissions
between 2008 and 2017 35 and
contended that planned shutdowns and
33 It is unclear whether Kentucky intends to rely
on all of the data and policy approaches in
Appendix C as included in its submittal, or if these
documents were appended solely to support
specific policy and technical arguments relied on
by Kentucky in its submittal.
34 See the following Appendices to Appendix C—
Midwest Ozone Group Technical Support
Document: ‘‘Good Neighbor Modeling Technical
Support Document for 8-Hour Ozone
Implementation Plans of Kentucky’s January 11,
2019: Appendix A—4km Modeling Results for MidAtlantic and Lake Michigan Domains Compared to
EPA 12 km ‘‘No Water’’ Design Value Calculations
from March 2018 Memorandum; Appendix B—
Midwest Ozone Group Comments on EPA’s March
27, 2018 Memorandum Entitled ‘‘Information on
the Interstate Transport State Implementation Plan
Submissions for the 2015 Ozone National Ambient
Air Quality Standards under Clean Air Act Section
110(a)(2)(D)(i)(I); Appendix C—Presentation—
Midwest Ozone Group Preview of 2015 Ozone
NAAQS Good Neighbor SIPs.
35 Table 2 in Kentucky’s SIP provides historic
annual NOX emissions data for point sources in the
state from 2008 through 2016, however, the
associated graph at Chart 1 indicates annual NOX
emissions from 2008 through 2017.
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conversion to natural gas, along with the
implementation of Federal and State
programs, ensure Kentucky’s emissions
will continue to decrease. Based on the
2014 national emission inventory (NEI),
Kentucky indicated that the major
contributor of NOX emissions in the
Commonwealth are point sources,
mainly comprised of electric generating
units (EGUs).
Kentucky asserted that NOX emissions
from EGUs in the Commonwealth have
decreased and would continue to
decrease based, in part, on the
implementation of CAIR, CSAPR, and
the CSAPR Update, as well as
retirements of several EGUs in the
Commonwealth. The Commonwealth
compared Kentucky’s NOX ozone season
allocations to actual EGU emissions in
the Commonwealth, concluding that
Kentucky’s NOX ozone season budgets
have decreased since the
implementation of CSAPR and the
CSAPR Update and actual ozone season
NOX emissions are significantly lower
than the trading program budgets.36 The
SIP submission summarized coal-fired
unit retirements, shutdowns, and
repowering from 2015 through 2017 as
well as on-the-way reductions from
natural gas conversions and retirements
from 2017 through 2023.37 Kentucky
stated that it expected emissions will
continue to decline in the future due to
continued implementation of CSAPR,
the CSAPR Update, and scheduled
shutdowns, fuel switches, and
retirements of facilities in the
Commonwealth.
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B. Information Related to Connecticut
Monitors Provided by Kentucky
EPA’s March 2018 modeling showed
Kentucky linked to the two receptors
located in Fairfield County,
Connecticut, which is part of the New
York-Northern New Jersey-Long Island,
NY-NJ-CT (New York Metro Area) core
based statistical area (CBSA).38
Kentucky applied an alternative
contribution threshold of 1 ppb, and
thus determined that Kentucky was no
longer linked to the Connecticut
36 Kentucky’s SIP acknowledged that the CSAPR
trading program does not address interstate
transport for the 2015 standard but nonetheless
provides NOX emission reductions.
37 See Kentucky’s January 11, 2019, submittal
located in Docket No. EPA–R04–OAR–2021–0841,
at pages 32–33 for discussion on implementation of
CSAPR, the CSAPR Update, EGU retirements, and
EGU fuel switches.
38 EPA’s designations for the 2015 8-hour ozone
standard divided the state into two areas, Greater
Connecticut, CT, with a marginal classification, and
New York-Northern New Jersey-Long Island, NYNJ-CT (New York Metro Area), with a moderate
classification. See https://www.epa.gov/ozonedesignations/additional-designations-2015-ozonestandards.
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receptors. In addition, Kentucky
provided information intended to
demonstrate that emissions from local
sources in the area surrounding the
monitors contribute significantly to the
continued nonattainment issues, and
thus, that local controls should be
implemented before requesting upwind
states to control facilities.
In particular, Kentucky’s SIP
submission claims that the Westport
Sherwood, Fairfield, Connecticut (ID:
90019003) and Stratford Point
Lighthouse, Fairfield County (ID:
90013007) monitors are located less
than three miles from the I–95 interstate
highway corridor and over 500 miles
from Kentucky. Kentucky asserted these
monitors have a consistent pattern of
violating the 2015 8-hour ozone NAAQS
from 2007 to 2016. Kentucky also
pointed out that it is not linked in the
modeling to two other nonattainment
receptors (the Greenwich Point Park and
Criscuolo Park monitoring sites) that are
in relatively close proximity to the
Westport and Stratford monitors.
Kentucky compared the distances
between these sites with the distances of
the sites to Kentucky’s nearest border.
Kentucky’s SIP submission also
provided information related to the New
York Metro Area, citing the 2014 NEI to
state that the on-road source sector
contributed the highest amount of NOX
emissions and that the nonpoint source
sector contributed the highest amount of
VOC emissions in that area. The
Commonwealth further provided
information about high vehicle miles
traveled (VMT) and commuting patterns
in the New York Metro Area, as well as
information regarding violating
monitors along the I–95 corridor and
outlying monitors that show attainment.
Additionally, Kentucky’s SIP
submission includes Hybrid Single
Particle Lagrangian Integrated Trajectory
(HYSPLIT) model back trajectory
analysis to the two Connecticut
receptors,39 asserting that the HYSPLIT
analysis indicates that the monitors are
downwind of nonattainment areas in
New York, New Jersey, Pennsylvania,
and Maryland. The Commonwealth also
asserted there is a consistent pattern of
violating monitors located along the I–
95 corridor. In addition, Kentucky
asserted that pollutants are trapped in
the marine boundary layer and then
transported inland to coastal
39 According to Kentucky, the HYSPLIT analysis
were generated using EPA’s 2015 Ozone
Designation Mapping Tool, available at https://
www.epa.gov/ozone-designations/ozonedesignations-guidance-and-data#:∼:text=The
%20ozone%20designations%20mapping
%20tool,for%20the%202015
%20Ozone%20NAAQS.
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Connecticut receptors due to conditions
on Long Island Sound.
The Commonwealth’s SIP submission
also discussed point sources in the New
York Metro Area, providing information
regarding the largest point sources in
that area. In addition, Kentucky
provided NOX and VOC emission
information for 13 counties in the New
York Metro Area that have NOX and
VOC emission totals above 10,000 tpy,
finding that three counties that
surround Fairfield County (Suffolk,
Queens, and Nassau Counties) had the
highest NOX emissions.
Kentucky further evaluated high
electric demand days in New York,
discussing a New York Department of
Environmental Conservation (NYDEC)
determination that peaking units
operating on peak electricity demand
days are a major contributor of NOX
(particularly units installed before
1987), and that such units can
contribute 4.8 ppb of ozone on high
ozone days.40 Kentucky concluded NOX
emission reductions from these EGUs
point sources would have a significant
impact on ozone levels in the New York
Metro Area.
C. Information Related to the Harford,
Maryland Monitor Provided by Kentucky
Kentucky acknowledged that EPA’s
March 27, 2018 modeling shows the
potential for Kentucky emissions to
significantly contribute to the
Edgewood, Harford County, Maryland
(ID: 240251001) maintenance-only
monitor (Edgewood monitor) in 2023.
However, Kentucky provided air quality
data designed to demonstrate that
emissions from local sources in the area
surrounding the monitors contribute
significantly to the continued air quality
issues and concluded that there are
local controls that should be
implemented before requesting upwind
states to control facilities.
Kentucky provided additional
information with respect to the
Edgewood Monitor, which is located 3
miles from the I–95 corridor and
approximately 350 miles from
Kentucky. Kentucky provided data to
show that the Edgewood monitor
consistently violated the 2015 8-hour
ozone standard from 2007 to 2016.
Kentucky also provided information
related to other nonattainment monitors
located in Baltimore County and
Harford County.
The Commonwealth’s SIP submission
provided data related to the Baltimore40 Kentucky references NYDEC emission analysis
entitled ‘‘Background, High Electric Demand Day
(HEDD) Initiative’’, New York Department of
Environmental Conservation.
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Columbia-Towson, MD CBSA
(Baltimore Area), citing to the 2014 NEI
to state that the on-road source sector
contributed the highest amount of NOX
emissions and that the nonpoint source
sector contributed the highest amount of
VOC emissions in that area. Kentucky
further provided information about
VMTs and commuting patterns in the
Baltimore Area, as well as information
regarding violating monitors along the
I–95 corridor and outlying monitors that
show attainment. The SIP submission
asserted that local mobile emissions are
a key contributor to the Edgewood
monitor, which is also located in close
proximity to the 1–95 corridor.
Kentucky further cited to a presentation
and remarks by Maryland officials,
discussing programs to reduce
emissions from local sources,
specifically focusing on mobile source
NOX reduction programs.
Kentucky cited a 2010 case study in
the Chesapeake Bay that suggests the
transport of pollution from nearby urban
areas accumulates over the Bay and
becomes stagnant, creating a bay breeze
which is pushed by southerly winds
northward towards the Edgewood
monitor. Additionally, Kentucky’s SIP
submission also provided HYSPLIT
model back trajectory analysis to the
Edgewood receptor,41 asserting that the
HYSPLIT indicates that the monitors are
downwind of nonattainment areas in
Baltimore County, Baltimore City,
Arlington County, and the District of
Columbia. Kentucky also asserted that
higher altitude particles from the
northwest of Baltimore combine with
lower-level particles from the south and
southeast.
Kentucky’s submission used
information on local mobile emissions
along the I–95 corridor and coastal air
pollution formation and accumulation
along the Maryland coast to support its
conclusion that local air quality
problems are the source of ozone
violations at these monitors.
Additionally, Kentucky asserted that
the implementation of local programs to
reduce emissions should be sufficient
for monitors in the Maryland area to
attain the 2015 8-hour ozone NAAQS.
Kentucky cited claims by MOG
(appended to the submittal in Appendix
C) that the modeling in EPA’s March
2018 memorandum does not account for
additional retirements, conversions, and
41 According to Kentucky, the HYSPLIT analysis
were generated using EPA’s 2015 Ozone
Designation Mapping Tool, available at https://
www.epa.gov/ozone-designations/ozonedesignations-guidance-and-data#:∼:text=The
%20ozone%20designations%20mapping
%20tool,for%20the%202015%20Ozone
%20NAAQS.
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modifications or emission control
programs expected to be implemented
before 2023. Kentucky concluded that
because the Edgewood monitor is a
maintenance receptor, the
Commonwealth believes that no further
reductions from Kentucky sources other
than on-the-books controls should be
required because maintenance receptors
should be treated differently than
nonattainment receptors in terms of
upwind requirements. The
Commonwealth also asserted that states
linked to maintenance receptors should
be held to less stringent standards of
emissions reductions as compared to
states linked to a nonattainment
receptor.
The Commonwealth also asserted that
local emission controls should be
implemented before upwind states are
required to control their facilities,
which is based on Kentucky’s
concurrence with statements from MOG.
The Commonwealth cited MOG’s
comments on local controls stating:
‘‘When an area is measuring
nonattainment of a NAAQS, as is the
case with the areas linked to Kentucky,
the CAA requires that the effects and
benefits of local controls on all source
sectors be considered first, prior to
pursuing controls of sources in upwind
states.’’ 42 The Commonwealth
concluded that the emissions reductions
resulting from on-the-books and on-theway measures are adequate to prohibit
emissions within Kentucky from
interfering with the maintenance of
downwind states with respect to the
2015 8-hour ozone NAAQS.
results indicated that Kentucky
remained linked to the maintenanceonly receptor in Harford County,
Maryland, even after the application of
the 1 ppb alternative threshold,
Kentucky asserted that states should not
be required to apply the same degree of
reductions for maintenance receptors as
nonattainment areas, and determined
that additional NOX emission
reductions other than those that are onthe-books or on-the-way are not
required to address its downwind
contribution to that receptor. Kentucky
further provided an assessment of local
sources in the vicinity of the
Connecticut and Maryland monitors and
concluded that local (particularly
mobile) emissions, high VMTs and
commuting patterns, and weather
patterns are the primary cause of
violating monitors in these areas.
Therefore, Kentucky concluded that its
SIP has adequate provisions to prohibit
emissions from interfering with
maintenance in another state (i.e.,
‘‘prong 2’’ of CAA section
110(a)(2)(D)(i)(I)) with respect to the
2015 8-hour ozone NAAQS.
D. Summary of Conclusions From
Kentucky
In summary, based on Kentucky’s
reliance on the modeling results in
EPA’s March 2018 memorandum, the
Commonwealth found that emissions
from Kentucky sources were potentially
linked to four nonattainment monitors
in Connecticut and Wisconsin and one
maintenance receptor in Harford
County, Maryland. However, after
utilizing a 1 ppb alternative
contribution threshold, the
Commonwealth concluded that it was
no longer linked to the four
nonattainment monitors, and thus, that
the Kentucky SIP contains adequate
provisions to prevent sources and other
types of emissions activities within the
State from contributing significantly to
nonattainment in any other state (i.e.,
‘‘prong 1’’ of CAA section
110(a)(2)(D)(i)(I)) for the 2015 8-hour
ozone NAAQS. Although modeling
E. Summary of Midwest Ozone Group
TSD Appended to Kentucky’s Submittal
Kentucky attached several materials
developed by MOG to its submittal as
Appendix C, which included a
document titled ‘‘ ‘Good Neighbor’
Modeling Technical Support Document
for 8-Hour Ozone State Implementation
Plans’’ prepared by Alpine
Geophysics.43 The Alpine Geophysics
document also attached the following
documents: 4 kilometer (km) modeling
results for mid-Atlantic and Lake
Michigan domains compared to EPA 12
km ‘‘No Water’’ Design Value
Calculations from March 2018
memorandum (Appendix A); MOG
comments on EPA’s March 2018
memorandum (Appendix B); and a
Microsoft PowerPoint presentation from
MOG previewing 2015 8-hour ozone
NAAQS good neighbor SIPs (Appendix
C). EPA notes a number of modeling
results and technical and policy
arguments provided in the MOG
attachments are not explicitly discussed
in Kentucky’s SIP submission narrative.
Therefore, it is unclear whether
Kentucky intended to rely on Alpine’s
modeling or MOG’s policy argument to
support the Commonwealth’s overall
transport SIP conclusions. To ensure
review of all potentially relevant
technical and policy issues identified in
Kentucky’s SIP package, this section
summarizes key arguments presented in
42 Kentucky’s SIP references MOG’s comments
that cite CAA sections 107(a) and 110(a)(1).
43 See Appendix C of Kentucky’s January 11,
2019, transport SIP submission.
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Appendix C. However, in EPA’s
evaluation of the SIP submittal in
section III, EPA will differentiate
between those positions clearly adopted
by the Commonwealth and those where
it is unclear and therefore a position
espoused by MOG cannot be attributed
to Kentucky.
Appendix C included modeling
results performed by Alpine Geophysics
as presented in the Alpine TSD. The
Alpine modeling results identified the
Harford, Maryland receptor as a
nonattainment receptor, with Kentucky
emissions contributing 2.07 ppb. In
addition, the Alpine modeling results
identified Kentucky linkages above 1
percent to the following maintenanceonly receptors: Gloucester, New Jersey
(ID: 340150002), with a Kentucky
contribution of 1.69 ppb; Richmond,
New York (ID: 360850067), with a
Kentucky contribution of 0.93; and
Philadelphia, Pennsylvania (ID:
421010024), with a Kentucky
contribution of 1.53. (While MOG
asserts in separate comments that
emission reductions not accounted for
in EPA’s modeling suggests there will be
no receptors by 2023, this is not
consistent with Alpine’s modeling.)
The Alpine TSD also evaluated
additional approaches and flexibilities
that states could apply in SIP revisions,
based on the potential concepts
provided in Appendix A of EPA’s
March 2018 memorandum.44 These
included reliance on alterative modeling
data, evaluation of international
contributions (both anthropogenic
contribution and as an additional
percentage of boundary conditions),
alternate contribution thresholds,
proportional control of upwind
emissions by level of upwind state
contribution, and addressing
interference with maintenance
obligations through use of 10-year
projections.
MOG suggested states should be
allowed to select multiple sources of
modeling data rather than a single
modeling simulation if such information
is considered equally credible when
making policy decisions related to the
development of good neighbor SIPs.
With respect to international
emissions, MOG cited to an attachment
to EPA’s 2018 memorandum and asserts
44 See Section 9.0—Selected SIP Revision
Approaches in Appendix C—MOG’s TSD of
Kentucky’s January 11, 2019 transport SIP
submission.
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that EPA’s and Alpine’s contribution
modeling tracks and reports the relative
impact contributions of anthropogenic
emissions located within the 36 km
modeling domain. Considering this
information, MOG concluded that states
seeking to avoid overcontrol may wish
to consider removing that portion of the
projected design value that is explicitly
attributed to international
anthropogenic contribution, which may
be enough to demonstrate attainment
with the 2008 or 2015 8-hour ozone
NAAQS at multiple monitors in the U.S.
With respect to potential use of
alternative contribution thresholds,
MOG pointed to states raising concerns
that the 1 percent threshold is more
stringent than the 2016 EPA Significant
Impact level (SIL) guidance of 1 ppb,
which is designed as an individual
source or group of sources’ contribution
limit (in the context of prevention of
significant deterioration (PSD)
permitting).45 MOG suggested that states
could submit SIP revisions citing the
SIL of 1 ppb as an acceptable total state
anthropogenic contribution threshold
under Step 2 of the 4-step process, and
request relief from the 1 percent
threshold in lieu of using an alternate
value.
MOG presented an alternative
approach to how upwind-state emission
reduction obligations could be
allocated. Specifically, MOG proposed
that upwind reductions could be
allocated in proportion to the size of
their contribution to downwind
nonattainment. To illustrate this
approach, MOG determined a
proportional reduction requirement
associated with the relative contribution
from each upwind state to the Harford
County, Maryland monitor. Under this
analysis, MOG’s approach indicated that
Kentucky would be responsible for a
0.02 ppb reduction at the monitor and
‘‘would then need to craft a [good
neighbor SIP] revision to generate
reductions associated with this
proportional amount.’’
With respect to ‘‘interference with
maintenance’’ obligations, MOG
suggested that an upwind state could
45 MOG cited to the Georgia Environmental
Protection Division’s comment on EPA’s March
2018 Memorandum to support this claim. See
Section 9.0—Selected SIP Revision Approaches in
Appendix C—MOG’s TSD of Kentucky’s January 11,
2019 transport SIP submission, citing Boylan, J. W.
(May 4, 2018). Georgia EPD Comments on EPA’s
March 27, 2018 Interstate Transport Memo
[Memorandum].
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choose to indicate that no additional
controls would be needed to address a
maintenance monitor if the upwind
state can show that either the monitor
is likely to remain in attainment for a
period of 10 years or that the upwind
state’s emissions will not increase for 10
years after the attainment date.
III. EPA’s Evaluation of Kentucky’s
2015 8-Hour Ozone Interstate Transport
SIP Submission
EPA is proposing to find that
Kentucky’s January 11, 2019, SIP
submission does not meet the
Commonwealth’s obligations with
respect to prohibiting emissions that
contribute significantly to
nonattainment or interfere with
maintenance of the 2015 8-hour ozone
NAAQS in any other state based on
EPA’s evaluation of the SIP submission
using the 4-step interstate transport
framework, and therefore EPA is
proposing to disapprove Kentucky’s SIP
submission.
A. Results of EPA’s Step 1 and Step 2
Modeling and Findings for Kentucky
As described in section I, EPA
performed updated air quality modeling
to project design values and
contributions for 2023. These data were
examined to determine if Kentucky
contributes at or above the threshold of
1 percent of the 2015 8-hour ozone
NAAQS (0.70 ppb) to any downwind
nonattainment or maintenance receptor.
As shown in Table 1, the data 46 indicate
that in 2023, emissions from Kentucky
contribute greater than 1 percent of the
standard to nonattainment or
maintenance-only receptors in Bucks
County, Pennsylvania (ID: 420170012),
New Haven County, Connecticut (ID:
90099002), and Fairfield County,
Connecticut (ID: 90019003 and
90013007).47
46 The ozone design values and contributions at
individual monitoring sites nationwide are
provided in the file ‘‘2016v2_DVs_state_
contributions.xlsx’’ which is included in Docket
No. EPA–HQ–OAR–2021–0663.
47 These modeling results are consistent with the
results of a prior round of 2023 modeling using the
2016v1 emissions platform which became available
to the public in the fall of 2020 in the Revised
CSAPR Update, as noted in section I. That modeling
showed that Kentucky had a maximum contribution
greater than 0.70 ppb to at least one nonattainment
or maintenance-only receptor in 2023. These
modeling results are included in the file ‘‘Ozone
Design Values And Contributions Revised CSAPR
Update.xlsx’’ in Docket No. EPA–HQ–OAR–2021–
0663.
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TABLE 1—KENTUCKY LINKAGE RESULTS BASED ON EPA UPDATED 2023 MODELING
Location
County
Nonattainment/
maintenance
420170012 ........................
90099002 ..........................
90019003 ..........................
90013007 ..........................
Pennsylvania ....................
Connecticut ......................
Connecticut ......................
Connecticut ......................
Bucks ...............................
New Haven ......................
Fairfield ............................
Fairfield ............................
Maintenance .....................
Nonattainment ..................
Nonattainment ..................
Nonattainment ..................
B. Evaluation of Information Provided
by Kentucky Regarding Step 1
At Step 1 of the 4-step interstate
transport framework, Kentucky relied
on EPA modeling released in the March
2018 memorandum to identify
nonattainment and maintenance
receptors in 2023 and also included
results from modeling performed by
Alpine. As described previously in this
notice, EPA has recently updated its
2023 modeling using the most current
and technically appropriate
information. EPA proposes to rely on
EPA’s most recent modeling to identify
nonattainment and maintenance
receptors in 2023. However, even using
EPA modeling available to Kentucky at
the time of its SIP submittal, three
nonattainment receptors and one
maintenance-only receptor were
projected in 2023 to which Kentucky
was linked above 1 percent of the
NAAQS. In addition, the Alpine
modeling that Kentucky appended to its
submittal also indicated that Kentucky
was linked to several receptors in
2023.48 Kentucky appended comments
from MOG arguing that states should be
allowed to select multiple sources of
modeling data rather than a single
modeling simulation if such information
is considered equally credible when
making policy decisions related to the
development of good neighbor SIPs.
Whether EPA’s most recent 2023
modeling is relied on, or whether it is
considered in conjunction with its older
2023 modeling and/or the Alpine
modeling, the results consistently
identify several nonattainment or
maintenance receptors to which
Kentucky is linked above 1 percent of
the 2015 8-hour ozone NAAQS.
As discussed in section II.E, Kentucky
attached documents from MOG that
discussed international transport of
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2023 average
design value
(ppb)
Receptor ID
48 The Alpine modeling results identified the
Harford, Maryland receptor as a nonattainment
receptor, with Kentucky emissions contributing
2.07 ppb. In addition, the Alpine modeling results
identified Kentucky linkages above 1 percent to the
following maintenance-only receptors: Gloucester,
New Jersey (ID: 340150002), with a Kentucky
contribution of 1.69 ppb; Richmond, New York (ID:
360850067), with a Kentucky contribution of 0.93;
and Philadelphia, Pennsylvania (ID: 421010024),
with a Kentucky contribution of 1.53.
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emissions and their contribution to U.S.
ozone monitors, and argued that states
could remove that portion of the
projected design value explicitly
attributed to international
anthropogenic contribution. MOG
asserted that excluding the international
anthropogenic contributions could
result in attainment with the 2008 or
2015 8-hour ozone NAAQS at ozone
monitors in the United States, thus
potentially eliminating 2023 receptors.
Kentucky did not explicitly discuss in
its SIP submittal MOG’s arguments
regarding contributions from
international emissions and therefore it
is unclear if the Commonwealth
intended to rely on this argument to
support their conclusion, however, EPA
is providing its analysis related to these
arguments.
EPA disagrees that excluding
international contribution (whether
from North American international
anthropogenic, boundary conditions, or
other international sources) from the
projected design value of receptors is
acceptable under the CAA.49 The good
neighbor provision requires states and
EPA to address interstate transport of air
pollution that contributes to downwind
states’ ability to attain and maintain
NAAQS. Whether emissions from other
states or other countries also contribute
to the same downwind air quality issue
is irrelevant in assessing whether a
downwind state has an air quality
problem, or whether an upwind state is
significantly contributing to that
problem. States are not obligated under
CAA section 110(a)(2)(D)(i)(I) to reduce
emissions sufficient on their own to
resolve downwind receptors’
nonattainment or maintenance
problems. Rather, states are obligated to
eliminate their own ‘‘significant
contribution’’ or ‘‘interference’’ with the
49 To
the extent that MOG cited Attachment A to
EPA’s March 2018 memorandum as suggesting
support for this approach, this is incorrect. As
discussed in section I.D, the attachment
summarized ideas from outside stakeholders, and
EPA did not endorse such approaches as
technically or legally appropriate. Further, nothing
in Attachment A suggested that international
contribution could simply be subtracted from a
downwind receptor’s projected design value.
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70.7
71.8
76.1
74.2
2023
maximum
design value
(ppb)
72.2
73.9
76.4
75.1
Kentucky
contribution
(ppb)
0.88
0.83
0.82
0.77
ability of other states to attain or
maintain the NAAQS.
Indeed, the D.C. Circuit in Wisconsin
specifically rejected petitioner
arguments suggesting that upwind states
should be excused from good neighbor
obligations on the basis that some other
source of emissions (whether
international or another upwind state)
could be considered the ‘‘but-for’’ cause
of downwind air quality problem. See
938 F.3d at 323–324. The court viewed
petitioners’ arguments as essentially an
argument ‘‘that an upwind State
‘contributes significantly’ to downwind
nonattainment only when its emissions
are the sole cause of downwind
nonattainment.’’ See 938 F.3d at 324.
The court explained that ‘‘an upwind
State can ‘contribute’ to downwind
nonattainment even if its emissions are
not the but-for cause.’’ Id. at 324–325.
See also Catawba County v. EPA, 571
F.3d 20, 39 (D.C. Cir. 2009) (rejecting
the argument ‘‘that ‘significantly
contribute’ unambiguously means
‘strictly cause’ ’’ because there is ‘‘no
reason why the statute precludes EPA
from determining that [an] addition of
[pollutant] into the atmosphere is
significant even though a nearby
county’s nonattainment problem would
still persist in its absence’’); Miss.
Comm’n on Envtl. Quality v. EPA, 790
F.3d 138, 163 n.12 (D.C. Cir. 2015)
(observing that the argument that ‘‘there
likely would have been no violation at
all . . . if it were not for the emissions
resulting from [another source]’’ is
‘‘merely a rephrasing of the but-for
causation rule that we rejected in
Catawba County.’’). Therefore, a state is
not excused from eliminating its
significant contribution on the basis that
international emissions also contribute
some amount of pollution to the same
receptors to which the state is linked.
C. Evaluation of Information Provided
by Kentucky Regarding Step 2
At Step 2 of the 4-step interstate
transport framework, Kentucky relied
on EPA modeling released in the March
2018 memorandum to identify upwind
state linkages to nonattainment and
maintenance receptors in 2023 and
included results from modeling run by
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Alpine. Both EPA’s modeling released
in the March 2018 memorandum as well
as Alpine’s modeling indicate that
Kentucky is linked to downwind
monitors.50 As Kentucky attached
Alpine’s modeling without discussing it
in the narrative of the submittal, it is
unclear whether Kentucky intended to
rely on Alpine’s modeling in its
submittal.
As described in section I.C of this
notice, EPA has recently updated
modeling to identify upwind state
contributions to nonattainment and/or
maintenance receptors in 2023. In this
notice, EPA proposes to rely on the
Agency’s most recently available
modeling to identify upwind
contributions and ‘‘linkages’’ to
downwind air quality problems in 2023
using a threshold of 1 percent of the
NAAQS. See section I.D for a general
explanation of the use of 1 percent of
the NAAQS.
As shown in Table 1, updated EPA
modeling identifies Kentucky’s
maximum contribution to a downwind
nonattainment or maintenance receptor
is greater than 1 percent of the standard
(i.e., 0.70 ppb).
Kentucky, however, argued in its SIP
submittal for the use of an alternative 1
ppb contribution threshold at Step 2 to
attempt to demonstrate that it was no
longer ‘‘linked’’ to projected downwind
nonattainment receptors. Specifically,
Kentucky cited EPA’s August 2018
memorandum as supporting the use of
a 1 ppb alternative contribution
threshold at Step 2 to assert that the
Commonwealth was no longer ‘‘linked’’
to projected downwind nonattainment
receptors, while conceding that even
under this alternative threshold, it was
linked above 1 ppb to the projected
Harford, Maryland maintenance-only
receptor. EPA’s most recent modeling of
2023 no longer identifies the Harford,
Maryland monitoring site as either a
maintenance or nonattainment receptor.
Nonetheless, Kentucky is linked above 1
percent of the NAAQS but less than 1
ppb to the four receptors in EPA’s most
recent modeling. Therefore, whether
Kentucky’s use of an alternative 1 ppb
contribution threshold is approvable is
potentially a dispositive question in
EPA’s evaluation.
EPA proposes to find that Kentucky’s
reliance on an alternative contribution
threshold of 1 ppb at Step 2 is not
approvable. EPA acknowledges that the
50 Although the various modeling runs (EPA’s
March 2018 modeling, Alpine’s modeling and
EPA’s updated modeling) indicate that Kentucky is
linked to different receptors and with differing
amounts of contribution, all three sets of modeling
are consistent in that each indicates linkages
between Kentucky and downwind receptors.
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August 2018 memorandum generally
recognized that a 1 ppb threshold may
be appropriate for states to use, but also
made clear that this guidance would be
applied under the facts and
circumstances of each particular SIP
submittal.51 However, Kentucky did not
provide a technical analysis to
sufficiently justify use of an alternative
1 ppb threshold at the linked,
downwind monitors. Kentucky’s SIP
submission simply stated that the
Commonwealth agrees with EPA’s
rationale set out in the August 2018
memorandum that the amount of
upwind collective contribution captured
with the 1 percent and 1 ppb thresholds
was generally comparable. But the
guidance anticipated that states would
evaluate whether the alternative
threshold was appropriate under their
specific facts and circumstances, not
that the use of the alternative threshold
would be automatically approvable.52
With respect to the assertion that 1 ppb
was generally comparable to 1 percent,
Kentucky did not provide discussion or
analysis containing information specific
to Kentucky or a receptor analysis for
the affected monitors, as anticipated in
the 2018 memorandum, to evaluate
whether the alternative threshold was
appropriate to apply with respect to the
monitors to which Kentucky was linked.
Such state-specific information is
necessary to thoroughly evaluate the
state-specific circumstances that could
support approval. Given the absence of
technical analysis to support the use of
a 1 ppb threshold under the facts and
circumstances relevant to Kentucky and
its linked receptors, EPA proposes that
the use of 1 ppb as a contribution
threshold is not approvable.53 (As
discussed in section III.C.1 below, EPA
no longer intends to dedicate resources
to supplement state submittals with
51 See
August 2018 memorandum at 1.
an example of the type of analysis that EPA
anticipated states might conduct under the
guidance, in one instance, EPA itself attempted to
conduct a state- and receptor-specific analysis that
could support approval of the use of a 1 ppb
threshold. See Air Plan Approval; Iowa;
Infrastructure State Implementation Plan
Requirements for the 2015 Ozone National Ambient
Air Quality Standard, 85 FR 12232 (March 2, 2020).
The Agency received adverse comment on this
proposed approval and has not taken final action
with respect to this proposal.
53 Kentucky applied the 1 ppb contribution
threshold to the Connecticut, Wisconsin, and
Maryland receptors, as the Commonwealth found
that Kentucky was linked to these receptors based
on the modeling released with the March 2018
memorandum. Under EPA’s updated modeling,
Kentucky is no longer linked to the Wisconsin and
Maryland receptors and is linked to receptors in
Pennsylvania and New Haven, Connecticut. See
Table 1. However, as Kentucky did not provide any
state-specific information, the rationale is also
applicable to the Pennsylvania and New Haven,
Connecticut linkages.
52 As
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9509
insufficient analysis in this regard, and
also has identified other policy and
programmatic concerns with attempting
to recognize alternative thresholds at
Step 2 or otherwise deviating from its
historical, consistent practice since
CSAPR of applying a threshold of 1
percent of the NAAQS at Step 2.)
The MOG materials appended to
Kentucky’s submission argued that a
2016 EPA SIL guidance could be cited
as acceptable to support a 1 ppb
contribution threshold. As an initial
matter, Kentucky appears not to have
relied on this rationale. In EPA’s
comments on Kentucky’s draft SIP
submittal, EPA stated, ‘‘EPA has not
made a determination that the SIL,
developed for source-specific (PSD)
purposes, could be considered an
appropriate threshold to use when
assessing contribution from an entire
state.’’ 54 Kentucky stated in response
that it ‘‘concurs with the comment’’ and
had adjusted its SIP submittal
accordingly.55 Further, even if the State
had attempted to rely on the SIL as
support for a 1 ppb threshold, the basis
supplied by MOG is inadequate. The
SIL is an analytical metric used in the
context of PSD permitting, a part of the
CAA’s ‘‘prevention of significant
deterioration’’ program, which generally
is applicable in areas that designated
attainment 56 or unclassifiable for the
NAAQS. Good neighbor analysis for the
ozone NAAQS, by contrast, addresses
the degree of significant contribution to
nonattainment and interference with
maintenance of the NAAQS resulting at
downwind receptors from the collective
contribution of many upwind sources.
Further, it is not correct to conflate the
54 See Kentucky’s January 11, 2019, submission,
Appendix D, Summary of Comments and
Responses, at 6–7.
55 Id. at 7. EPA directed Kentucky instead to the
August 2018 memorandum if it wished to rely on
a 1 ppb threshold; however, EPA’s comments noted
that this memorandum was only a ‘‘part’’ of the
rationale the Commonwealth should develop. Id. at
6.
56 Pursuant to section 107(d) of the CAA, EPA
must designate areas as either ‘‘nonattainment,’’
‘‘attainment,’’ or ‘‘unclassifiable.’’ Historically for
ozone, the EPA has designated most areas that do
not meet the definition of nonattainment as
‘‘unclassifiable/attainment.’’ This category includes
areas that have air quality monitoring data meeting
the NAAQS and areas that do not have monitors but
for which the EPA has no evidence that the areas
may be violating the NAAQS or contributing to a
nearby violation. In the designations for the 2015
ozone NAAQS, the EPA reversed the order of the
label to be ‘‘attainment/unclassifiable’’ to better
convey the definition of the designation category
and so that the category is more easily
distinguished from the separate unclassifiable
category. An ‘‘attainment’’ designation is reserved
for a previous nonattainment area that has been
redesignated to attainment as a result of the EPA’s
approval of a CAA section 175A maintenance plan
submitted by the state air agency.
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use of the term ‘‘significance’’ as used
in the SIL guidance, with the term
‘‘contribution,’’ which is the appliable
statutory term that EPA applies at Step
2 of the 4-step interstate transport
framework. (‘‘Significance’’ within the
4-step framework is evaluated at Step 3
through a multifactor analysis, for those
states that are determined to
‘‘contribute’’ to downwind receptors at
Steps 1 and 2. See section I.D.4.) Given
the fundamentally different statutory
objectives and context, EPA disagrees
with MOG’s contention that the SIL
guidance is applicable in the good
neighbor context.
1. EPA’s Experience With Alternative
Step 2 Thresholds
EPA here shares further evaluation of
its experience since the issuance of the
August 2018 memorandum regarding
use of alternative thresholds at Step 2.
This experience leads the Agency to
now believe it may not be appropriate
to continue to attempt to recognize
alternative contribution thresholds at
Step 2. The August 2018 memorandum
stated that ‘‘it may be reasonable and
appropriate’’ for states to rely on an
alternative threshold of 1 ppb threshold
at Step 2.57 (The memorandum also
indicated that any higher alternative
threshold, such as 2 ppb, would likely
not be appropriate.) However, EPA also
provided that ‘‘air agencies should
consider whether the recommendations
in this guidance are appropriate for each
situation.’’ Following receipt and review
of 49 good neighbor SIP submittals for
the 2015 8-hour ozone NAAQS, EPA’s
experience has been that nearly every
state that attempted to rely on a 1 ppb
threshold did not provide sufficient
information and analysis to support a
determination that an alternative
threshold was reasonable or appropriate
for that state.
For instance, in nearly all submittals,
the states did not provide EPA with
analysis specific to their state or the
receptors to which its emissions are
potentially linked. In one case, the
proposed approval of Iowa’s SIP
submittal, EPA expended its own
resources to attempt to supplement the
information submitted by the state, in
order to more thoroughly evaluate the
state-specific circumstances that could
support approval.58 It was at EPA’s sole
discretion to perform this analysis in
August 2018 memorandum at 4.
Plan Approval; Iowa; Infrastructure State
Implementation Plan Requirements for the 2015
Ozone National Ambient Air Quality Standard, 85
FR 12232 (March 2, 2020). The Agency received
adverse comment on this proposed approval and
has not taken final action with respect to this
proposal.
support of the state’s submittal, and the
Agency is not obligated to conduct
supplemental analysis to fill the gaps
whenever it believes a state’s analysis is
insufficient. The Agency no longer
intends to undertake supplemental
analysis of SIP submittals with respect
to alternative thresholds at Step 2 for
purposes of the 2015 8-hour ozone
NAAQS.
Furthermore, EPA’s experience since
2018 is that allowing for alternative Step
2 thresholds may be impractical or
otherwise inadvisable for a number of
additional policy reasons. For a regional
air pollutant such as ozone, consistency
in requirements and expectations across
all states is essential. Based on its
review of submittals to-date and after
further consideration of the policy
implications of attempting to recognize
an alternative Step 2 threshold for
certain states, the Agency now believes
the attempted use of different thresholds
at Step 2 with respect to the 2015 8-hour
ozone NAAQS raises substantial policy
consistency and practical
implementation concerns.59 The
availability of different thresholds at
Step 2 has the potential to result in
inconsistent application of good
neighbor obligations based solely on the
strength of a state’s implementation
plan submittal at Step 2 of the 4-step
interstate transport framework. From the
perspective of ensuring effective
regional implementation of good
neighbor obligations, the more
important analysis is the evaluation of
the emissions reductions needed, if any,
to address a state’s significant
contribution after consideration of a
multifactor analysis at Step 3, including
a detailed evaluation that considers air
quality factors and cost. Where
alternative thresholds for purposes of
Step 2 may be ‘‘similar’’ in terms of
capturing the relative amount of upwind
contribution (as described in the August
2018 memorandum), nonetheless, use of
an alternative threshold would allow
certain states to avoid further evaluation
of potential emission controls while
other states must proceed to a Step 3
analysis. This can create significant
equity and consistency problems among
states.
Further, it is not clear that national
ozone transport policy is best served by
allowing for less stringent thresholds at
Step 2. EPA recognized in the August
2018 memorandum that there was some
57 See
58 Air
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59 EPA notes that Congress has placed on EPA a
general obligation to ensure the requirements of the
CAA are implemented consistently across states
and regions. See CAA section 301(a)(2). Where the
management and regulation of interstate pollution
levels spanning many states is at stake, consistency
in application of CAA requirements is paramount.
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similarity in the amount of total upwind
contribution captured (on a nationwide
basis) between 1 percent and 1 ppb.
However, EPA notes that while this may
be true in some sense, that is hardly a
compelling basis to move to a 1 ppb
threshold. Indeed, the 1 ppb threshold
has the disadvantage of losing a certain
amount of total upwind contribution for
further evaluation at Step 3 (e.g.,
roughly 7 percent of total upwind state
contribution was lost according to the
modeling underlying the August 2018
memorandum; 60 in EPA’s updated
modeling, the amount lost is 5 percent).
Considering the core statutory objective
of ensuring elimination of all significant
contribution to nonattainment or
interference of the NAAQS in other
states and the broad, regional nature of
the collective contribution problem with
respect to ozone, there does not appear
to be a compelling policy imperative in
allowing some states to use a 1 ppb
threshold while others rely on a 1
percent of the NAAQS threshold.
Consistency with past interstate
transport actions such as CSAPR, and
the CSAPR Update and Revised CSAPR
Update rulemakings (which used a Step
2 threshold of 1 percent of the NAAQS
for two less stringent ozone NAAQS), is
also important. Continuing to use a 1
percent of NAAQS approach ensures
that as the NAAQS are revised and
made more stringent, an appropriate
increase in stringency at Step 2 occurs,
so as to ensure an appropriately larger
amount of total upwind-state
contribution is captured for purposes of
fully addressing interstate transport. See
76 FR 48208, 48237–38 (August 8,
2011).
Therefore, notwithstanding the
August 2018 memorandum’s
recognition of the potential viability of
alternative Step 2 thresholds, and in
particular, a potentially applicable 1
ppb threshold, EPA’s experience since
the issuance of that memorandum has
revealed substantial programmatic and
policy difficulties in attempting to
implement this approach. Nonetheless,
EPA is not at this time rescinding the
August 2018 memorandum. The basis
for disapproval of Kentucky’s SIP
submission with respect to the Step 2
analysis is, in the Agency’s view,
warranted even under the terms of the
August 2018 memorandum. EPA invites
comment on this broader discussion of
issues associated with alternative
thresholds at Step 2. Depending on
comment and further evaluation of this
issue, EPA may determine to rescind the
August 2018 memorandum in the
future.
60 See
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In summary, EPA’s updated modeling
indicates that emissions from Kentucky
sources are linked to downwind
receptors identified in Table 1, and
application of 1 ppb alternative
threshold is not supported by
Kentucky’s SIP submission. Thus, EPA
preliminarily finds that Kentucky is
linked to downwind nonattainment and
maintenance receptors, and proceeds to
Step 3 of the 4-step framework.
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D. Evaluation of Information Provided
by Kentucky Regarding Step 3
At Step 3 of the 4-step interstate
transport framework, a state’s emissions
are further evaluated, in light of
multiple factors, including air quality
and cost considerations, to determine
what, if any, emissions significantly
contribute to nonattainment or interfere
with maintenance and, thus, must be
eliminated under CAA section
110(a)(2)(D)(i)(I).
To effectively evaluate which
emissions in the state should be deemed
‘‘significant’’ and therefore prohibited,
states generally should prepare an
accounting of sources and other
emissions activity for relevant
pollutants and assess potential,
additional emissions reduction
opportunities and resulting downwind
air quality improvements. EPA has
consistently applied this general
approach (i.e., Step 3 of the 4-step
interstate transport framewor46k) when
identifying emissions contributions that
the Agency has determined to be
‘‘significant’’ (or interfere with
maintenance) in each of its prior
Federal, regional ozone transport
rulemakings, and this interpretation of
the statute has been upheld by the
Supreme Court. See EME Homer City,
572 U.S. 489, 518–520 (2014). While
EPA has not directed states that they
must conduct a Step 3 analysis in
precisely the manner EPA has done in
its prior regional transport rulemakings,
state implementation plans addressing
the obligations in CAA section
110(a)(2)(D)(i)(I) must prohibit ‘‘any
source or other type of emissions
activity within the State’’ from emitting
air pollutants which will contribute
significantly to downwind air quality
problems. Thus, states must complete
something similar to EPA’s analysis (or
an alternative approach to defining
‘‘significance’’ that comports with the
statute’s objectives) to determine
whether and to what degree emissions
from a state should be ‘‘prohibited’’ to
eliminate emissions that will
‘‘contribute significantly to
nonattainment in, or interfere with
maintenance of’’ the NAAQS in any
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other state. Kentucky did not conduct
such an analysis in its SIP submission.
Kentucky did not include a
comprehensive accounting of facilities
in the Commonwealth and did not
include a sufficient analysis of potential
NOX emissions control technologies,
their associated costs, estimated
emissions reductions, and downwind
air quality improvements for the
purpose of identifying what additional
emission controls may be necessary to
eliminate their significant contribution.
Rather, Kentucky’s SIP included air
quality analysis related to downwind
receptors and relied on existing NOX
emission measures in the
Commonwealth without any rationale to
show how or why existing measures
would eliminate the Kentucky’s
downwind contribution. Further, the
Commonwealth provided information
related to programs that it asserted were
responsible for a 10-year decline in
ozone season NOX emissions in
Kentucky, such as regulations and
Federal programs (including the CSAPR
Update), EGU shutdowns, retirements,
and fuel switches. However, Kentucky
did not quantify the NOx emission
reduction potential of on-the-books
regulations or Federal programs or onthe-way measures for 2023, nor does the
submission consider cost-effectiveness
of potential emissions controls, the total
emissions reductions that may be
achieved by requiring these controls, or
an evaluation of the air quality impacts
such emissions reductions would have
on the downwind receptors to which
Kentucky is linked. Identifying a range
of on-the-books emissions control
measures that have been or may be
enacted at the state or local level,
without analysis of the impact of those
measures on the downwind receptors, is
not a sufficient analysis.
Furthermore, the emissions-reducing
effects of on-the-books emissions
control requirements are already
reflected in the air quality results of
EPA’s modeling under Steps 1 and 2 of
the 4-step framework. Kentucky, and
MOG in the materials it submitted to
Kentucky, maintain that there were
additional emission reductions that
have occurred that were not accounted
for in EPA’s 2023 modeling as presented
in the March 2018 memorandum.
Kentucky cites the 2019 retirement of
units 1 and 2 at the E.W. Brown coalfired power plant (see Appendix D,
Response to Comments, at 5), and MOG
claims a variety of unidentified changes
not accounted for in EPA’s emissions
inventory at the time of the modeling in
the March 2018 memorandum, as well
as certain downwind state measures
apparently under consideration but not
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9511
adopted, and certain changes in the
Wisconsin EGU fleet (see Alpine TSD,
Appendix B, at pages B–5, B–6). In
general, any changes in the emissions
inventory and on-the-books controls
relevant to emissions in 2023 have now
been incorporated into EPA’s most
recent modeling of 2023. This includes
changes in Kentucky EGU emissions.
As previously discussed, EPA’s
updated modeling indicates sources in
Kentucky are linked to downwind air
quality problems for the 2015 8-hour
ozone standard. However, Kentucky’s
SIP submittal did not include a
sufficient accounting of emissions
sources or activity in the
Commonwealth, along with an analysis
of potential NOX emissions control
technologies, associated costs, estimated
emissions reductions, and downwind
air quality improvements to eliminate
the Kentucky’s downwind contribution.
EPA therefore propose to find that
Kentucky was required to analyze
emissions from the sources and other
emissions activity from within the
Commonwealth to determine whether
its contributions were significant, and
EPA proposes to disapprove its
submission because Kentucky failed to
do so.
The subsections below contain
additional detail with respect to
arguments made by the Commonwealth
in its SIP submission.61
1. Evaluation of Kentucky’s Reliance on
Existing and Future NOX Emission
Reductions
The Commonwealth’s SIP submission
does not contain a Step 3 analysis
regarding future emissions reduction
opportunities beyond pointing to NOX
emission reductions from expected
retirements, fuel switching, and
shutdowns. While the Commonwealth
claimed there would be an estimated
471 tons of NOX emissions from
potential shutdown of units at the E.W.
Brown Generating Station facility in
Harrodsburg, Kentucky, the
Commonwealth did not clarify how
these planned reductions would resolve
the Commonwealth’s downwind
contribution to the Harford County,
Maryland maintenance-only receptor by
2023. (Nor did the Commonwealth
evaluate whether emissions may
increase at other sources whose
generation would replace that lost at
E. W. Brown.) Further, the E.W. Brown
facility retired coal-fired units 1 and 2
61 These subsections provide brief summaries of
the issues as presented in Kentucky’s SIP as
context; please see section II of this notice for
additional detail on the contents of Kentucky’s SIP.
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in February 2019,62 the units’ retirement
is included in the recently updated
modeling for Steps 1 and 2, and yet
emissions from Kentucky sources
remain linked to one or more downwind
receptors.
While the Commonwealth generally
asserted that on-the-books or on-the-way
regulations and programs may provide
future emissions reductions, Kentucky
did not quantify these reductions in a
meaningful way or demonstrate that the
downwind improvements from these
regulations and programs would be
sufficient to eliminate the
Commonwealth’s significant
contribution or interference with
maintenance. In addition, the SIP
submission did not evaluate or even
attempt to identify additional control
measures for EGUs or non-EGUs, nor
did it include a determination of
emission reduction potential for these
potential additional controls or consider
their cost-effectiveness or downwind air
quality effects. This is not a sufficient
Step 3 analysis.
2. Evaluation of Kentucky’s Reliance on
Prior Transport FIPs
The 10-year emission reductions
discussed by Kentucky relies in part on
the implementation of CAIR, CSAPR,
and the CSAPR Update. Kentucky’s SIP
relied on its EGUs being subject to the
CSAPR Update (which reflected a
stringency at the nominal marginal cost
threshold of $1,400/ton (in 2011 dollars)
for the 2008 8-hour ozone NAAQS) to
argue that it has already implemented
all cost-effective emissions reductions to
support its conclusion that additional
NOX emission reductions are not
necessary from sources in Kentucky.
Kentucky did not conduct a
comprehensive Step 3 analysis or
provide any justification for reliance on
the CSAPR Update beyond identifying
the NOX emission reductions that the
Commonwealth believes are the source
of the 10-year decline in NOX emissions
at EGUs in the Commonwealth and
noting that the actual emissions from
EGUs in the Commonwealth are well
below the CSAPR Update NOX ozone
season trading budget.
EPA disagrees with the
Commonwealth. Reliance on the CSAPR
Update (or the subsequent Revised
CSAPR Update, which fully resolved
Kentucky’s good neighbor obligations
for the 2008 ozone NAAQS, 86 FR
23056–57), is insufficient because those
policies addressed section
110(a)(2)(D)(i)(I) only for the 2008 ozone
62 See Retired Unit exemption forms for E.W.
Brown Generating station in Docket No.: EPA–R04–
OAR–2021–0841.
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NAAQS. Additionally, reliance on an
alleged cost-threshold stringency from
the CSAPR Update is insufficient
without additional Step 3 analysis and
justification. First, the CSAPR Update
did not regulate non-EGUs, and thus
this analysis would have been
incomplete, even with respect to
obligations under the 2008 ozone
NAAQS. See Wisconsin, 938 F.3d at
318–20. Second, relying on the CSAPR
Update’s (or any other CAA program’s)
determination of cost-effectiveness
without further Step 3 analysis is not
approvable. Cost-effectiveness must be
assessed in the context of the specific
CAA program; assessing costeffectiveness in the context of ozone
transport should reflect a more
comprehensive evaluation of the nature
of the interstate transport problem
under the relevant NAAQS, the total
emissions reductions available at
alternative cost thresholds, and the air
quality impacts of the reductions at
downwind receptors. While EPA has
not established a benchmark costeffectiveness value for 2015 8-hour
ozone NAAQS interstate transport
obligations, because the 2015 8-hour
ozone NAAQS is a more stringent and
more protective air quality standard, it
is reasonable to expect control measures
or strategies to address interstate
transport under this NAAQS to reflect
higher marginal control costs. As such,
the marginal cost threshold of $1,400/
ton for the CSAPR Update (which
addresses the 2008 ozone 8-hour
NAAQS and is in 2011 dollars) is not an
appropriate cost threshold and cannot
be approved as a benchmark to use for
interstate transport SIP submissions for
the 2015 8-hour ozone NAAQS.
In addition, the updated EPA
modeling captures all existing CSAPR
trading programs in the baseline, and
that modeling confirms that these
control programs were not sufficient to
eliminate the Kentucky’s linkage at
Steps 1 and 2 under the 2015 8-hour
ozone NAAQS. Kentucky was therefore
obligated at Step 3 to assess additional
control measures using a multifactor
analysis.
Finally, relying on a FIP at Step 3 is
per se not approvable if the state has not
adopted that program into its SIP and
instead continues to rely on the FIP.
States may not rely on non-SIP
measures to meet SIP requirements. See
CAA section 110(a)(2)(D) (‘‘Each such
[SIP] shall . . . contain adequate
provisions. . . .’’). See also CAA
section 110(a)(2)(A); Committee for a
Better Arvin v. U.S. E.P.A., 786 F.3d
1169, 1175–76 (9th Cir. 2015) (holding
that measures relied on by state to meet
CAA requirements must be included in
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the SIP). Kentucky has not adopted the
Group 3 NOX Ozone Season Trading
Program promulgated in the Revised
CSAPR Update into its SIP.
3. Evaluation of Kentucky’s Analysis of
Air Quality and Emission Reductions
Near the Linked Monitors
Kentucky’s SIP also evaluated air
quality in the vicinity of the Fairfield
County, Connecticut (IDs: 090013007
and 090019003) and Harford County,
Maryland (ID: 240251001) monitors for
which the Commonwealth is linked
based on EPA’s modeling in the March
2018 memorandum. Kentucky’s
submission asserts that the primary
cause of nonattainment problems at the
Connecticut and Maryland monitors are
due to local emissions of ozone
precursors (particularly NOX) and
meteorological conditions.
Kentucky’s SIP submittal argues
against control requirements on
Kentucky sources to address the two
nonattainment receptors in Fairfield,
Connecticut (IDs: 090013007,
090019003) and the maintenance-only
monitor in Harford County, Maryland
monitor, claiming that additional
emission reductions from Kentucky
EGUs (the only Kentucky source
category discussed in the submittal) are
not necessary. Kentucky concludes that
local emissions reductions should be
applied before requiring Kentucky to
control its sources, and that the
implementation of local programs to
reduce emissions should be sufficient
for monitors in the area to attain the
2015 8-hour ozone NAAQS.63
With respect to the information
Kentucky provided that is related to
local emissions and the impact on air
quality at the Connecticut and Maryland
receptors, this information is
insufficient to approve Kentucky’s SIP
submission. Regardless of whether local
emissions are the largest contributor to
a specific nonattainment or
maintenance receptor, the good
neighbor provision requires that upwind
states prohibit emissions that contribute
significantly to nonattainment or
interfere with maintenance of the
NAAQS in downwind states. EPA
evaluates a state’s obligations to
eliminate interstate transport emissions
under the interstate transport provision
according to EPA’s 4-step process, and
EPA’s updating modeling at Steps 1 and
63 The Commonwealth’s submission cites to
MOG’s statements regarding controls on local
sources ‘‘When an area is measuring nonattainment
of a NAAQS, as is the case with the areas linked
to Kentucky, the CAA requires that the effects and
benefits of local controls on all source sectors be
considered first, prior to pursuing controls of
sources in upwind states.’’
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2 has identified a linkage between
emission from Kentucky sources and
downwind nonattainment and
maintenance receptors.
Further, EPA disagrees with
Kentucky’s claims that local emissions
reductions from the jurisdiction where
the downwind receptor is located must
first be implemented and accounted for
before imposing obligations on upwind
states under the interstate transport
provision. There is nothing in the CAA
that supports that position, and it does
not provide grounds on which to
approve Kentucky SIP submission. The
D.C. Circuit has held on five different
occasions that the timing framework for
addressing interstate transport
obligations must be consistent with the
downwind areas’ attainment schedule.
In particular, for the ozone NAAQS, the
states and EPA are to address interstate
transport obligations ‘‘as expeditiously
as practicable’’ and no later than the
attainment schedule set in accordance
with CAA section 181(a). See North
Carolina, 531 F.3d at 911–13;
Wisconsin, 938 F.3d at 313–20;
Maryland, 958 F.3d at 1204; New York
v. EPA, 964 F.3d 1214, 1226 (D.C. Cir.
2020); New York v. EPA, 781 Fed. App’x
4, 6–7 (D.C. Cir. 2019). The court in
Wisconsin explained its reasoning in
part by noting that downwind
jurisdictions often may need to heavily
rely on emissions reductions from
upwind states in order to achieve
attainment of the NAAQS, 938 F.3d at
316–17; such states would face
increased regulatory burdens including
the risk of bumping up to a higher
nonattainment classification if
attainment is not reached by the
relevant deadline. Maryland, 958 F.3d at
1204. The statutory framework of the
CAA and these cases establish clearly
that states and EPA must address
interstate transport obligations in line
with the attainment schedule provided
in the Act in order to timely assist
downwind states in attaining and
maintain the NAAQS, and this schedule
is ‘‘central to the regulatory scheme.’’
Wisconsin, 938 F.3d at 316 (quoting
Sierra Club v. EPA, 294 F.3d 155, 161
(D.C. Cir. 2002)).
In addition, Kentucky’s SIP does not
provide a technical justification to
support its conclusion that local
emissions reductions at the receptors
will achieve attainment without upwind
reductions from sources within
Kentucky. Specifically, Kentucky does
not provide any information to support
its claim that the implementation of
local programs alone will address the air
quality problems at the Connecticut and
Maryland monitors. Even with the
consideration of on-the-books control
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measures to reduce mobile source
emissions, EPA’s modeling projects that
the total contribution from upwind
states is a substantial part of the ozone
problem at the nonattainment and
maintenance receptors to which
Kentucky is linked. To illustrate this, at
the four receptors to which Kentucky is
linked in EPA’s latest 2023 modeling,
the total percent of U.S. anthropogenic
emissions from upwind states is 55
percent (Bucks Co., Pennsylvania), 90
percent (New Haven Co., Connecticut),
90 percent (Fairfield Co.—Stratford,
Connecticut), and 94 percent (Fairfield
Co.—Westport, Connecticut) of the total
design values at these receptors. Clearly,
emissions reductions from upwind
states would have an impact on the
design values at the identified
receptors.64
Additionally, the SIP submission does
not assess whether the Commonwealth’s
own emissions contributed to
nonattainment or interfered with
maintenance at the linked receptors, or
rather substantiate that emissions from
the Commonwealth’s sources were not
interacting with these monitors.
Consequently, the application of local
emission reduction measures does not
absolve upwind states and sources from
the responsibility of addressing their
significant contribution. Moreover,
Kentucky still has an obligation under
the Act to address its downwind
contribution to ozone nonattainment or
interference with maintenance
regardless of the emission reduction
potential for local control measures.
Furthermore, given that EPA’s updated
modeling indicates that Kentucky is
linked to nonattainment and
maintenance receptors at Step 2
including the same Fairfield County,
Connecticut nonattainment receptors as
were linked in the modeling released
with the March 2018 memorandum,
EPA disagrees with Kentucky’s claims
regarding the application of local
emission reduction measures with
respect to its downwind linkages in the
most recent modeling.
64 In contrast to the receptors to which Kentucky
is linked, EPA has found that certain receptors are
so heavily impacted by local emissions that they
should not be considered ‘‘transport’’ receptors for
purposes of the ozone NAAQS. Typically, in such
cases, only one state is linked above 1 percent to
that receptor and the total upwind state
contribution is on the order of 2 percent to 4
percent of the receptor’s DV. See, e.g., 81 FR 15200
(March 22, 2016), 81 FR 31513 (May 19, 2016), and
81 FR 36179 (June 6, 2016) (approving Arizona’s
transport SIP on basis that certain California
receptors should not be considered impacted by
interstate ozone transport).
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4. Evaluation of Kentucky’s HYSPLIT
Analysis
Kentucky’s SIP submittal also
included HYSPLIT model back
trajectory analysis, which Kentucky
used to emphasize the local nature of
the ozone precursor emissions at the
two Connecticut receptors, mobile
sources along the I–95 Corridor, and the
proximity of large point sources and
ozone nonattainment areas in New
York, New Jersey, Pennsylvania, and
Maryland. Similarly, Kentucky also
evaluated HYSPLIT back-trajectory for
the Harford County, Maryland monitor
and noted similar localized emissions
impacts with respect to the Maryland
monitor as discussed previously for the
two Fairfield County, Connecticut
monitors.
However, the limited information
provided by Kentucky is not adequate to
support approval of Kentucky’s SIP on
this basis and in the absence of a more
complete Step 3 evaluation. Kentucky’s
SIP submittal did not address that the
HYSPLIT back-trajectories indicate that
ozone precursor emissions sources in
Kentucky are upwind of the linked
nonattainment receptors in Connecticut
(regardless of the existence of other
upwind nonattainment areas that may
also be contributing to those receptors).
Additionally, the HYSPLIT trajectory
information provided by Kentucky was
developed by EPA to inform the 2015
8-hour ozone NAAQS area designations
and was not intended to evaluate longdistance interstate transport.65
Attachment 3 of the 2015 8-hour
ozone Area Designations memorandum
states that the line thickness displayed
on trajectory plots ‘‘does not imply
coverage other than to represent the
centerline of an air parcel’s motion
calculated to arrive at the starting
location at the starting time.
Uncertainties are clearly present in
these results and these uncertainties
change with trajectory time and distance
traveled. One should avoid concluding
a region is not along a trajectory’s path
if the center line of that trajectory
missed the region by a relatively small
distance.’’ 66
65 See Area Designations for the 2015 Ozone
National Ambient Air Quality Standards
memorandum from Janet G. McCabe to EPA
Regional Administrators, February 25, 2016 (2015
ozone Area Designations memorandum).
66 See id. It is important to understand that
HYSPLIT back trajectory analyses use archived
meteorological modeling that includes actual
observed data (surface, upper air, airplane data,
etc.) and modeled meteorological fields to estimate
the most likely route of an air parcel transported to
a receptor at a specified time. The method
essentially follows a parcel of air backward in
hourly steps for a specified length of time. HYSPLIT
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Further, the back trajectories used by
Kentucky were limited to evaluating
transport of air parcels over a relatively
short 24-hour period, which limits their
use for evaluating long-distance
transport of emissions from Kentucky to
the Fairfield, Connecticut receptors and
the Harford, Maryland receptor. In
contrast, EPA’s analysis of transported
emissions as discussed in section III.A
uses updated, photochemical grid
modeling designed to assess ozone
transported to downwind monitors
across the entire region and over
extended timeframes that fully account
for fate and transport of ozoneprecursors over longer distances.
Kentucky’s SIP submission states that
the Fairfield County ozone monitors are
located in the New York Metro Area, in
close proximity to the I–95
transportation artery. The
Commonwealth’s analysis asserts a high
VMT and number of commuters in the
area indicating the presence of mobile
emissions that could be the cause of
violating monitors along the I–95
corridor. Kentucky’s SIP also mentions
two additional coastal monitor sites
(Westport Sherwood and Stratford Point
Lighthouse) located less than three
miles from the I–95 corridor that also
show a pattern of ozone violations.
Kentucky raises similar points regarding
the effect of mobile source emissions
along the I–95 corridor in Maryland
near the Edgewood receptor. Further,
Kentucky asserts that both the
Connecticut and Maryland receptor sites
may be particularly impacted by unique
coastal conditions associated with the
Long Island Sound and the Chesapeake
Bay. While it is true that both of these
monitors are affected by coastal
meteorological conditions such as
complex land-water wind flows and
mixing heights, a large portion of
anthropogenic ozone at these locations
is the result of transport from upwind
states. In addition, as noted above,
EPA’s most recent modeling shows that
Kentucky is linked to a receptor in
Bucks County, Pennsylvania which is
inland and not influenced by coastal
meteorology.
The relevance of the points raised by
Kentucky regarding the HYSPLIT back
trajectories related to the evaluation of
Kentucky’s good neighbor obligations is
estimates the central path in both the vertical and
horizontal planes. The HYSPLIT central path
represents the centerline with the understanding
that there are areas on each side horizontally and
vertically that also contribute to the end point at the
monitor. The horizontal and vertical areas from the
centerline grow wider the further back in time the
trajectory goes. Therefore, a HYSPLIT centerline
does not have to pass directly over emissions
sources or emission source areas but merely
relatively near emission source areas.
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not clear. As already discussed, the
statute and the case law (particularly the
holdings in Wisconsin and Maryland)
make clear that good neighbor
obligations are not merely
supplementary to or deferable until after
local emission reductions are achieved.
Further, all of the receptors to which
Kentucky is linked are heavily impacted
by upwind state emissions in addition
to local sources and conditions. The
Wisconsin decision’s holding regarding
international contribution (discussed in
section III.A) is equally applicable to an
upwind state’s claims that some other
state’s emissions, or local emissions, are
‘‘more to blame’’ than its own
emissions. See 938 F.3d 303 at 323–25
(‘‘an upwind State can ‘contribute’ to
downwind nonattainment even if its
emissions are not the but-for cause’’).
5. Evaluation of Kentucky’s Approach to
Maintenance Receptors
Kentucky’s SIP argues that states
linked only to maintenance receptors
should be held to less stringent
standards of emissions reductions
compared to states linked to a
nonattainment receptor. Thus, as the
Edgewood monitor was identified as a
maintenance receptor in EPA’s March
2018 memorandum modeling, the
Commonwealth asserts that no further
reductions from Kentucky sources other
than on-the-books controls should be
required. Although the Harford monitor
is no longer linked to Kentucky based
on EPA’s updated modeling,67
emissions from the Commonwealth are
linked to the Bucks County,
Pennsylvania (ID: 420170012)
maintenance-only receptor.
Additionally, MOG argues that states
should be absolved from additional
emissions controls to address a
maintenance monitor if the upwind
state can show that either the monitor
is likely to remain in attainment for a
period of 10 years or that the upwind
state’s emissions will not increase for 10
years after the attainment date.68
67 See
Table 1, shown previously in this notice.
68 Kentucky did not rely on MOG’s proposed
approach in its SIP submittal, therefore EPA does
not comprehensively evaluate MOG’s suggestion.
However, EPA’s definition of maintenance
receptors already accounts for, and projects
whether, receptors may have trouble attaining the
NAAQS, through the use of projected maximum
design values in the relevant analytic year. Further,
EPA’s modeling of the relevant analytic year also
already accounts for projected emissions trends of
the upwind state (among others) and may (and often
does) identify a linkage to areas that may struggle
to maintain the NAAQS despite an overall
declining emissions trend. This is not surprising.
First, most maintenance receptors in EPA’s
projections are currently measuring nonattainment,
meaning that, despite projecting improved air
quality in the future analytic year, the receptor
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Under the D.C. Circuit’s decision in
North Carolina, states and EPA are
required to give independent
significance to the ‘‘interference with
maintenance’’ prong of section
110(a)(2)(D)(i)(I). See 531 F.3d at 910.
Since CSAPR, EPA’s nationally
consistent policy framework for
addressing interstate ozone transport
has given meaning to this prong through
a separate definition of maintenance
receptors at Step 1 of the 4-step
interstate transport framework. For
states linked only to those receptors,
EPA has found it appropriate to apply
an emissions control solution that is
uniform with the strategy applied for
states that are linked to nonattainment
receptors. See 76 FR at 48271. EPA’s
approach to addressing interference
with maintenance under prong 2 for
ozone NAAQS has been upheld twice.
See EME Homer City Generation, L.P.,
795 F.3d at 136; Wisconsin, 938 F.3d at
325–27. See also 86 FR at 23054 (April
30, 2021).69
Particularly given this context,
Kentucky’s SIP submission does not
provide information sufficient to
support less stringent standards of
emissions reductions than would result
from EPA’s historical approach of
addressing emissions activities from
upwind states that are linked to
maintenance-only receptors. The
Commonwealth does not explain how
the obligations of upwind states linked
to maintenance-only receptors should
be treated differently than the
obligations of upwind states linked to
nonattainment receptors.
Further, EPA believes it would be
inconsistent with the CAA for EPA to
identify receptors that are at risk of
NAAQS violations given certain
conditions due to transported upwind
emissions and then not prohibit the
emissions that place the receptor at risk.
The Supreme Court held that it was a
permissible interpretation of the statute
to apportion responsibility for states
location is currently, and may continue to be, near
the level of the NAAQS. Second, ozone levels are
influenced by meteorological variability and thus
high ozone levels may persist despite declining
emissions as a result of recurring or worsening
ozone-conducive atmospheric conditions (e.g.,
higher temperatures). It is unclear how MOG’s
approach would account for this variability or
ensure that projected emissions reductions from
linked states are rendered certain and enforceable.
69 In the main text of its SIP submittal conclusion
regarding interstate transport, Kentucky incorrectly
attributes statements regarding the ‘‘interfere with
maintenance’’ prong to the U.S. Supreme Court. See
Submittal at 45–46. A footnote, however, correctly
attributes this language to the D.C. Circuit’s original
opinion in EME Homer City v EPA, 696 F.3d 7 (D.C.
Cir. 2012). This decision was reversed and
remanded by the Supreme Court, and on remand,
the D.C. Circuit affirmed EPA’s approach to
implementing prong 2, see 795 F.3d at 136.
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linked to nonattainment receptors
considering ‘‘both the magnitude of
upwind States’ contributions and the
cost associated with eliminating them.’’
EME Homer City, 134 S. Ct. at 1606. It
is equally reasonable and permissible to
use these factors to apportion
responsibility among upwind states
linked to maintenance receptors because
the goal in both instances is to prohibit
the ‘‘amounts’’ of pollution that will
either significantly contribute to
nonattainment or interfere with
maintenance of the NAAQS downwind.
EPA’s updated modeling indicates that
the Commonwealth is still linked to
downwind nonattainment and
maintenance receptors for the 2015 8hour ozone standard. Consequently,
EPA believes Kentucky’s assertion that
upwind states linked to maintenanceonly receptors should be held to less
stringent standards of emissions
reductions (as compared to states linked
to a nonattainment receptor) is also
inappropriate for new downwind
linkages.
6. Evaluation of Weighted Step 3
Approach
Although Kentucky did not adopt this
approach in its SIP submittal, the MOG
materials Kentucky appended provided
arguments suggesting a ‘‘weighted’’
approach to Step 3 similar to an
approach that stakeholders had
identified to EPA (as listed in
Attachment A to EPA’s March 2018
memorandum). Under this approach,
upwind-state emission reduction
obligations would be allocated in
proportion to the size of their
contribution to downwind
nonattainment. MOG determined the
proportional reduction requirement
associated with the relative significant
contribution from each upwind state to
the Harford County, Maryland monitor
including Kentucky, which resulted in
an additional emission reduction
obligation for Kentucky of 0.02 ppb, as
MOG proposed would be the
appropriate proportion of reductions
necessary for attainment at the Harford
receptor. This approach would have
imposed additional emissions
reductions for Kentucky sources.
Kentucky’s final SIP did not consider
MOG’s proposal, and did not provide an
explanation for why it was rejecting this
approach to allocating upwind emission
reductions, even though it appended
this recommendation to its SIP
submittal.
In summary, EPA has newly available
information that confirms sources in
Kentucky are linked to downwind air
quality problems for the 2015 8-hour
ozone standard. Kentucky’s SIP
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submittal did not include an accounting
of emissions sources and activity in the
Commonwealth along with an analysis
of potential NOX emissions control
technologies, their associated costs,
estimated emissions reductions, and
downwind air quality improvements.
Nor did Kentucky present an alternative
approach to assess which of its
emissions should be deemed
‘‘significant.’’ EPA proposes to find that
Kentucky’s analysis—including reliance
on on-the-books state and Federal
measures (including prior CSAPR
programs) and claimed on-the-way
emission reductions, as well as other air
quality, emissions, and geographic
factors—is insufficient to support the
Commonwealth’s claim that its SIP
adequately prohibits emissions within
Kentucky in a manner sufficient to
address the State’s interstate transport
obligations for the 2015 8-hour ozone.
E. Evaluation of Information Provided
by Kentucky Regarding Step 4
Step 4 of the 4-step interstate
transport framework calls for
development of permanent and
federally enforceable control strategies
to achieve the emissions reductions
determined to be necessary at Step 3 to
eliminate significant contribution to
nonattainment or interference with
maintenance of the NAAQS. Kentucky
indicates that certain upcoming planned
fuel switches or shutdowns at EGUs will
occur before the end of 2023, for which
Kentucky cites a press release and a
closure plan developed by each plant’s
parent company.70 As discussed in
section III.D., Kentucky’s analysis is
insufficient to demonstrate that these
reductions are sufficient to address the
Commonwealth’s interstate transport
obligations; however, the
Commonwealth also did not provide a
separate SIP revision to ensure the
reductions were permanent and
enforceable. As a result, EPA proposes
to disapprove Kentucky’s January 11,
2019, submittal on the separate,
additional basis that the Commonwealth
has not developed permanent and
enforceable emissions reductions
necessary to meet the obligations of
CAA section 110(a)(2)(d)(i)(I).
F. Conclusion
Based on EPA’s evaluation of
Kentucky’s SIP submission, EPA is
70 Pointing to anticipated upcoming emission
reductions, even if they were not included in the
analysis at Steps 1 and 2, is not sufficient as a Step
3 analysis, for the reasons discussed in section III.C.
In this section, EPA explain that to the extent such
anticipated reductions are not included in the SIP
and rendered permanent and enforceable, reliance
on such anticipated reductions is also insufficient
at Step 4.
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9515
proposing to find that the interstate
transport portion of Kentucky’s January
11, 2019, SIP submission addressing
CAA section 110(a)(2)(D)(i)(I) does not
meet the Commonwealth’s interstate
transport obligations because it fails to
contain the necessary provisions to
eliminate emissions that will contribute
significantly to nonattainment or
interfere with maintenance of the 2015
8-hour ozone NAAQS in any other state.
IV. Proposed Action
EPA is proposing to disapprove the
2015 8-hour ozone good neighbor
interstate transport SIP revision from
Kentucky, dated January 11, 2019.
Under CAA section 110(c)(1), if
finalized, this disapproval would
establish a 2-year deadline for EPA to
promulgate a FIP for Kentucky to
address the CAA section
110(a)(2)(D)(i)(I) interstate transport
requirements pertaining to significant
contribution to nonattainment and
interference with maintenance of the
2015 8-hour ozone NAAQS in other
states, unless EPA approves a SIP that
meets these requirements. However,
under the CAA, a good neighbor SIP
disapproval does not start a mandatory
sanctions clock.
V. Statutory and Executive Order
Reviews
A. Executive Order 12866: Regulatory
Planning and Review and Executive
Order 13563: Improving Regulation and
Regulatory Review
This proposed action is not a
significant regulatory action and was
therefore not submitted to the Office of
Management and Budget for review.
B. Paperwork Reduction Act (PRA)
This proposed action does not impose
an information collection burden under
the PRA because it does not contain any
information collection activities.
C. Regulatory Flexibility Act (RFA)
This action merely proposes to
disapprove a SIP submission as not
meeting the CAA for Kentucky. EPA
certifies that this proposed rule will not
have a significant economic impact on
a substantial number of small entities
under the RFA (5 U.S.C. 601 et seq.).
D. Unfunded Mandates Reform Act
(UMRA)
This proposed 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 proposed action
imposes no enforceable duty on any
state, local, or tribal governments or the
private sector.
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E. Executive Order 13132: Federalism
This proposed 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: Consultation
and Coordination With Indian Tribal
Governments
This proposed action does not have
tribal implications as specified in
Executive Order 13175. This proposed
action does not apply on any Indian
reservation land, any other area where
EPA or an Indian tribe has demonstrated
that a tribe has jurisdiction, or nonreservation areas of Indian country.
Thus, Executive Order 13175 does not
apply to this action.
G. Executive Order 13045: Protection of
Children From Environmental Health
Risks and Safety Risks
EPA interprets Executive Order 13045
as applying only to those regulatory
actions that concern environmental
health or safety risks that 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 proposed action
is not subject to Executive Order 13045
because it merely proposes to
disapprove a SIP submission from
Kentucky as not meeting the CAA.
H. Executive Order 13211, Actions That
Significantly Affect Energy Supply,
Distribution or Use
This proposed 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
This proposed rulemaking does not
involve technical standards.
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J. Executive Order 12898: Federal
Actions To Address Environmental
Justice in Minority Populations and
Low-Income Populations
EPA believes the human health or
environmental risk addressed by this
action will not have potential
disproportionately high and adverse
human health or environmental effects
on minority, low-income or indigenous
populations. This action merely
proposes to disapprove a SIP
submission as not meeting the CAA.
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K. CAA Section 307(b)(1)
Section 307(b)(1) of the CAA governs
judicial review of final actions by EPA.
This section provides, in part, that
petitions for review must be filed in the
D.C. Circuit: (i) When the agency action
consists of ‘‘nationally applicable
regulations promulgated, or final actions
taken, by the Administrator,’’ or (ii)
when such action is locally or regionally
applicable, if ‘‘such action is based on
a determination of nationwide scope or
effect and if in taking such action the
Administrator finds and publishes that
such action is based on such a
determination.’’ For locally or regionally
applicable final actions, the CAA
reserves to EPA complete discretion
whether to invoke the exception in
(ii).71
If EPA takes final action on this
proposed rulemaking, the Administrator
intends to exercise the complete
discretion afforded to him under the
CAA to make and publish a finding that
the final action (to the extent a court
finds the action to be locally or
regionally applicable) is based on a
determination of ‘‘nationwide scope or
effect’’ within the meaning of CAA
section 307(b)(1). Through this
rulemaking action (in conjunction with
a series of related actions on other SIP
submissions for the same CAA
obligations), EPA interprets and applies
section 110(a)(2)(d)(i)(I) of the CAA for
the 2015 8-hour ozone NAAQS based on
a common core of nationwide policy
judgments and technical analysis
concerning the interstate transport of
pollutants throughout the continental
U.S. In particular, EPA is applying here
(and in other proposed actions related to
the same obligations) the same,
nationally consistent 4-step framework
for assessing good neighbor obligations
for the 2015 8-hour ozone NAAQS. EPA
relies on a single set of updated, 2016base year photochemical grid modeling
results of the year 2023 as the primary
basis for its assessment of air quality
conditions and contributions at Steps 1
and 2 of that framework. Further, EPA
proposes to determine and apply a set
of nationally consistent policy
judgments to apply the 4-step
framework. EPA has selected a
nationally uniform analytic year (2023)
for this analysis and is applying a
nationally uniform approach to
71 In deciding whether to invoke the exception by
making and publishing a finding that an action is
based on a determination of nationwide scope or
effect, the Administrator takes into account a
number of policy considerations, including his
judgment balancing the benefit of obtaining the D.C.
Circuit’s authoritative centralized review versus
allowing development of the issue in other contexts
and the best use of agency resources.
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nonattainment and maintenance
receptors and a nationally uniform
approach to contribution threshold
analysis.72 For these reasons, the
Administrator intends, if this proposed
action is finalized, to exercise the
complete discretion afforded to him
under the CAA to make and publish a
finding that this action is based on one
or more determinations of nationwide
scope or effect for purposes of CAA
section 307(b)(1).73
List of Subjects in 40 CFR Part 52
Environmental protection, Air
pollution control, Incorporation by
reference, Ozone.
Authority: 42 U.S.C. 7401 et seq.
Dated: February 3, 2022.
Daniel Blackman,
Regional Administrator, Region 4.
[FR Doc. 2022–02947 Filed 2–18–22; 8:45 am]
BILLING CODE 6560–50–P
ENVIRONMENTAL PROTECTION
AGENCY
40 CFR Part 52
EPA–R03–OAR–2021–0873; EPA–HQ–OAR–
2021–0663; FRL–9494–01–R3]
Air Plan Disapproval; West Virginia;
Interstate Transport of Air Pollution for
the 2015 8-Hour Ozone National
Ambient Air Quality Standard
Environmental Protection
Agency (EPA).
ACTION: Proposed rule.
AGENCY:
Pursuant to the Federal Clean
Air Act (CAA or the Act), the
Environmental Protection Agency (EPA)
is proposing to disapprove a State
Implementation Plan (SIP) submittal
from West Virginia intended to address
interstate transport for the 2015 8-hour
ozone national ambient air quality
standards (2015 8-hour ozone NAAQS).
The ‘‘good neighbor’’ or ‘‘interstate
SUMMARY:
72 A finding of nationwide scope or effect is also
appropriate for actions that cover states in multiple
judicial circuits. In the report on the 1977
Amendments that revised section 307(b)(1) of the
CAA, Congress noted that the Administrator’s
determination that the ‘‘nationwide scope or effect’’
exception applies would be appropriate for any
action that has a scope or effect beyond a single
judicial circuit. See H.R. Rep. No. 95–294 at 323,
324, reprinted in 1977 U.S.C.C.A.N. 1402–03.
73 EPA may take a consolidated, single final
action on all of the proposed SIP disapproval
actions with respect to obligations under CAA
section 110(a)(2)(D)(i)(I) for the 2015 8-hour ozone
NAAQS. Should EPA take a single final action on
all such disapprovals, this action would be
nationally applicable, and EPA would also
anticipate, in the alternative, making and
publishing a finding that such final action is based
on a determination of nationwide scope or effect.
E:\FR\FM\22FEP1.SGM
22FEP1
]]>Agencies
[Federal Register Volume 87, Number 35 (Tuesday, February 22, 2022)]
[Proposed Rules]
[Pages 9498-9516]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2022-02947]
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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 52
[EPA-R04-OAR-2021-0841; EPA-HQ-OAR-2021-0663; FRL-9423-01-R4]
Air Plan Disapproval; Kentucky; Interstate Transport Requirements
for the 2015 8-Hour Ozone National Ambient Air Quality Standards
AGENCY: Environmental Protection Agency (EPA).
ACTION: Proposed rule.
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SUMMARY: Pursuant to the Federal Clean Air Act (CAA or the Act), the
Environmental Protection Agency (EPA or Agency) is proposing to
disapprove a State Implementation Plan (SIP) submittal from the
Kentucky Energy and Environment Cabinet, Department of Environmental
Quality (DAQ) (herein after referred to as Kentucky or the
Commonwealth) regarding the interstate transport requirements for the
2015 8-hour ozone national ambient air quality standards (NAAQS or
standard). The ``Good Neighbor'' or ``Interstate Transport'' provision
requires that each state's implementation plan contain adequate
provisions to prohibit emissions from within the state from
significantly contributing to nonattainment or interfering with
maintenance of the NAAQS in other states. This requirement is part of
the broader set of ``infrastructure'' requirements, which are designed
to ensure that the structural components of each state's air quality
management program are adequate to meet the state's responsibilities
under the CAA. This disapproval, if finalized, will establish a 2-year
deadline for EPA to promulgate a Federal Implementation Plan (FIP) to
address the relevant interstate transport requirements, unless EPA
approves a subsequent SIP submittal that meets these requirements.
Disapproval does not start a mandatory sanctions clock.
DATES: Comments must be received on or before April 25, 2022.
Withdrawals: As of February 22, 2022, the proposed rule published
in December 30, 2019, at 84 FR 71854, is withdrawn.
ADDRESSES: You may submit comments, identified by Docket No. EPA-R04-
OAR-2021-0841, through the Federal eRulemaking Portal at https://www.regulations.gov following the online instructions for submitting
comments.
Instructions: All submissions received must include the Docket No.
EPA-R04-OAR-2021-0841 for this rulemaking. Comments received may be
posted without change to https://www.regulations.gov/, including any
personal information provided. For detailed instructions on submitting
comments and additional information on the rulemaking process, see the
``Public Participation'' heading of the SUPPLEMENTARY INFORMATION
section of this document. Out of an abundance of caution for members of
the public and staff, the EPA Docket Center and Reading Room are open
to the public by appointment only to reduce the risk of transmitting
COVID-19. The Docket Center staff also continues to provide remote
customer service via email, phone, and webform. For further information
on EPA Docket Center services and the current status, please visit EPA
online at https://www.epa.gov/dockets.
FOR FURTHER INFORMATION CONTACT: Evan Adams of the Air Regulatory
Management Section, Air Planning and Implementation Branch, Air and
Radiation Division, U.S. Environmental Protection Agency, Region 4, 61
Forsyth Street SW, Atlanta, Georgia 30303-8960. Mr. Adams can be
reached by telephone at (404) 562-9009, or via electronic mail at
[email protected].
SUPPLEMENTARY INFORMATION: Public Participation: Submit your comments,
identified by Docket No. EPA-R04-OAR-2021-0841, at https://www.regulations.gov. Once submitted, comments cannot be edited or
removed from the docket. EPA may publish any comment received to its
public docket. Do not submit to EPA's docket at https://www.regulations.gov any information you consider to be Confidential
Business Information (CBI) or other information whose disclosure is
restricted by statute. Multimedia submissions (audio, video, etc.) 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. 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).
[[Page 9499]]
There are two dockets supporting this action, EPA-R04-OAR-2021-0841
and EPA-HQ-OAR-2021-0663. Docket No. EPA-R04-OAR-2021-0841 contains
information specific to Kentucky, including this notice of proposed
rulemaking. Docket No. EPA-HQ-OAR-2021-0663 contains additional
modeling files, emissions inventory files, technical support documents,
and other relevant supporting documentation regarding interstate
transport of emissions for the 2015 8-hour ozone NAAQS which are being
used to support this action. All comments regarding information in
either of these dockets are to be made in Docket No. EPA-R04-OAR-2021-
0841. 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. Due to public health concerns related to COVID-19, the EPA
Docket Center and Reading Room are open to the public by appointment
only. The Docket Center staff also continues to provide remote customer
service via email, phone, and webform. For further information and
updates on EPA Docket Center services, please visit EPA online at
https://www.epa.gov/dockets.
EPA continues to carefully and continuously monitor information
from the Centers for Disease Control and Prevention (CDC), local area
health departments, and Federal partners so that EPA can respond
rapidly as conditions change regarding COVID-19.
The indices to Docket No. EPA-R04-OAR-2021-0841 and Docket No. EPA-
HQ-OAR-2021-0663 are available electronically at www.regulations.gov.
While all documents in each docket are listed in their respective
index, some information may not be publicly available due to docket
file size restrictions or content (e.g., CBI).
Table of Contents
I. Background
A. Description of Statutory Background
B. Description of EPA's Four Step Interstate Transport
Regulatory Process
C. Background on EPA's Ozone Transport Modeling Information
D. EPA's Approach to Evaluating Interstate Transport SIPs for
the 2015 8-Hour Ozone NAAQS
II. Summary of Kentucky's 2015 8-Hour Ozone Interstate Transport SIP
Submission
A. Information Related to Emission Trends From Kentucky Sources
B. Information Related to Connecticut Monitors Provided by
Kentucky
C. Information Related to the Harford, Maryland Monitor Provided
by Kentucky
D. Summary of Conclusions From Kentucky
E. Summary of Midwest Ozone Group TSD Appended to Kentucky's
Submittal
III. EPA's Evaluation of Kentucky's 2015 8-Hour Ozone Interstate
Transport SIP Submission
A. Results of EPA's Step 1 and Step 2 Modeling and Findings for
Kentucky
B. Evaluation of Information Provided by Kentucky Regarding Step
1
C. Evaluation of Information Provided by Kentucky Regarding Step
2
D. Evaluation of Information Provided by Kentucky Regarding Step
3
E. Evaluation of Information Provided by Kentucky Regarding Step
4
F. Conclusion
IV. Proposed Action
V. Statutory and Executive Order Reviews
I. Background
The following provides background for EPA's proposed action related
to the interstate transport requirements for the 2015 8-hour ozone
NAAQS for the Commonwealth of Kentucky.
A. Description of Statutory Background
On October 1, 2015, EPA promulgated a revision to the ozone NAAQS
(2015 8-hour ozone NAAQS), lowering the level of both the primary and
secondary standards to 0.070 parts per million (ppm).\1\ Section
110(a)(1) of the CAA requires states to submit, within 3 years after
promulgation of a new or revised standard, SIP submissions meeting the
applicable requirements of section 110(a)(2).\2\ One of these
applicable requirements is found in CAA section 110(a)(2)(D)(i)(I),
otherwise known as the ``good neighbor'' or ``interstate transport''
provision, which generally requires SIPs to contain adequate provisions
to prohibit in-state emissions activities from having certain adverse
air quality effects on other states due to interstate transport of
pollution. There are two so-called ``prongs'' within CAA section
110(a)(2)(D)(i)(I). A SIP for a new or revised NAAQS must contain
adequate provisions prohibiting any source or other type of emissions
activity within the state from emitting air pollutants in amounts that
will significantly contribute to nonattainment of the NAAQS in another
state (prong 1) or interfere with maintenance of the NAAQS in another
state (prong 2). EPA and states must give independent significance to
prong 1 and prong 2 when evaluating downwind air quality problems under
CAA section 110(a)(2)(D)(i)(I).\3\
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\1\ National Ambient Air Quality Standards for Ozone, Final
Rule, 80 FR 65292 (October 26, 2015). Although the level of the
standard is specified in the units of ppm, ozone concentrations are
also described in parts per billion (ppb). For example, 0.070 ppm is
equivalent to 70 ppb.
\2\ SIP revisions that are intended to meet the applicable
requirements of section 110(a)(1) and (2) of the CAA are often
referred to as infrastructure SIPs and the applicable elements under
section 110(a)(2) are referred to as infrastructure requirements.
\3\ See North Carolina v. EPA, 531 F.3d 896, 909-11 (D.C. Cir.
2008).
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B. Description of EPA's Four Step Interstate Transport Regulatory
Process
EPA is using the 4-step interstate transport framework (or 4-step
framework) to evaluate the states' implementation plan submittals
addressing the interstate transport provision for the 2015 8-hour ozone
NAAQS. EPA has addressed the interstate transport requirements of CAA
section 110(a)(2)(D)(i)(I) with respect to prior ozone NAAQS in several
regional regulatory actions, including the Cross-State Air Pollution
Rule (CSAPR), which addressed interstate transport with respect to the
1997 ozone NAAQS as well as the 1997 and 2006 fine particulate matter
standards,\4\ the Cross-State Air Pollution Rule Update (CSAPR Update)
\5\ and the Revised CSAPR Update, both of which addressed the 2008
ozone NAAQS.\6\
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\4\ See Federal Implementation Plans: Interstate Transport of
Fine Particulate Matter and Ozone and Correction of SIP Approvals,
76 FR 48208 (August 8, 2011).
\5\ Cross-State Air Pollution Rule Update for the 2008 Ozone
NAAQS, 81 FR 74504 (October 26, 2016).
\6\ In 2019, the United States Court of Appeals for the District
of Columbia Circuit (D.C. Circuit) remanded the CSAPR Update to the
extent it failed to require upwind states to eliminate their
significant contribution by the next applicable attainment date by
which downwind states must come into compliance with the NAAQS, as
established under CAA section 181(a). Wisconsin v. EPA, 938 F.3d
303, 313 (D.C. Cir. 2019). The Revised CSAPR Update for the 2008
Ozone NAAQS, 86 FR 23054 (April 30, 2021), responded to the remand
of the CSAPR Update in Wisconsin and the vacatur of a separate rule,
the ``CSAPR Close-Out,'' 83 FR 65878 (December 21, 2018), in New
York v. EPA, 781 F. App'x. 4 (D.C. Cir. 2019).
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Through the development and implementation of the CSAPR rulemakings
and prior regional rulemakings pursuant to the interstate transport
provision,\7\ EPA, working in partnership with states, developed the
following 4-step interstate transport framework to evaluate a state's
obligations to eliminate interstate transport emissions under the
interstate transport provision for the ozone NAAQS: (1) Identify
monitoring sites that are projected to have problems attaining and/or
maintaining the NAAQS (i.e., nonattainment and/or maintenance
receptors); (2) identify
[[Page 9500]]
states that impact those air quality problems in other (i.e., downwind)
states sufficiently such that the states are considered ``linked'' and
therefore warrant further review and analysis; (3) identify the
emissions reductions necessary (if any), applying a multifactor
analysis, to eliminate each linked upwind state's significant
contribution to nonattainment or interference with maintenance of the
NAAQS at the locations identified in Step 1; and (4) adopt permanent
and enforceable measures needed to achieve those emissions reductions.
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\7\ In addition to CSAPR rulemakings, other regional rulemakings
addressing ozone transport include the ``NOX SIP Call,''
63 FR 57356 (October 27, 1998), and the ``Clean Air Interstate
Rule'' (CAIR), 70 FR 25162 (May 12, 2005).
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C. Background on EPA's Ozone Transport Modeling Information
In general, EPA has performed nationwide air quality modeling to
project ozone design values which are used in combination with measured
data to identify nonattainment and maintenance receptors. To quantify
the contribution of emissions from specific upwind states on 2023 ozone
design values for the identified downwind nonattainment and maintenance
receptors, EPA performed nationwide, state-level ozone source
apportionment modeling for 2023. The source apportionment modeling
provided contributions to ozone at receptors from precursor emissions
of anthropogenic nitrogen oxides (NOX) and volatile organic
compounds (VOCs) in individual upwind states.
EPA has released several documents containing projected design
values, contributions, and information relevant to evaluating
interstate transport with respect to the 2015 8-hour ozone NAAQS.
First, on January 6, 2017, EPA published a notice of data availability
(NODA) in which the Agency requested comment on preliminary interstate
ozone transport data including projected ozone design values and
interstate contributions for 2023 using a 2011 base year platform.\8\
In the NODA, EPA used the year 2023 as the analytic year for this
preliminary modeling because that year aligns with the expected
attainment year for Moderate ozone nonattainment areas for the 2015 8-
hour ozone NAAQS.\9\ On October 27, 2017, EPA released a memorandum
(October 2017 memorandum) containing updated modeling data for 2023,
which incorporated changes made in response to comments on the NODA,
and noted that the modeling may be useful for states developing SIPs to
address interstate transport obligations for the 2008 ozone NAAQS.\10\
On March 27, 2018, EPA issued a memorandum (March 2018 memorandum)
noting that the same 2023 modeling data released in the October 2017
memorandum could also be useful for identifying potential downwind air
quality problems with respect to the 2015 8-hour ozone NAAQS at Step 1
of the 4-step interstate transport framework.\11\ The March 2018
memorandum also included the then newly available contribution modeling
data for 2023 to assist states in evaluating their impact on potential
downwind air quality problems for the 2015 8-hour ozone NAAQS under
Step 2 of the 4-step interstate transport framework.\12\ EPA
subsequently issued two more memoranda in August and October 2018,
providing additional information to states developing interstate
transport SIP submissions for the 2015 8-hour ozone NAAQS concerning,
respectively, potential contribution thresholds that may be appropriate
to apply in Step 2 of the 4-step interstate transport framework, and
considerations for identifying downwind areas that may have problems
maintaining the standard at Step 1 of the 4-step interstate transport
framework.\13\
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\8\ See Notice of Availability of the Environmental Protection
Agency's Preliminary Interstate Ozone Transport Modeling Data for
the 2015 8-hour Ozone National Ambient Air Quality Standard (NAAQS),
82 FR 1733 (January 6, 2017).
\9\ See 82 FR 1733, 1735 (January 6, 2017).
\10\ See Information on the Interstate Transport State
Implementation Plan Submissions for the 2008 Ozone National Ambient
Air Quality Standards under Clean Air Act Section
110(a)(2)(D)(i)(I), October 27, 2017 (``October 2017 memorandum''),
available in Docket No. EPA-HQ-OAR-2021-0663 or at https://www.epa.gov/interstate-air-pollution-transport/interstate-air-pollution-transport-memos-and-notices.
\11\ See Information on the Interstate Transport State
Implementation Plan Submissions for the 2015 Ozone National Ambient
Air Quality Standards under Clean Air Act Section
110(a)(2)(D)(i)(I), March 27, 2018 (``March 2018 memorandum''),
available in Docket No. EPA-HQ-OAR-2021-0663 or at https://www.epa.gov/interstate-air-pollution-transport/interstate-air-pollution-transport-memos-and-notices.
\12\ The March 2018 memorandum, however, provided, ``While the
information in this memorandum and the associated air quality
analysis data could be used to inform the development of these SIPs,
the information is not a final determination regarding states'
obligations under the good neighbor provision. Any such
determination would be made through notice-and-comment rulemaking.''
\13\ See Analysis of Contribution Thresholds for Use in Clean
Air Act Section 110(a)(2)(D)(i)(I) Interstate Transport State
Implementation Plan Submissions for the 2015 Ozone National Ambient
Air Quality Standards, August 31, 2018) (``August 2018
memorandum''), and Considerations for Identifying Maintenance
Receptors for Use in Clean Air Act Section 110(a)(2)(D)(i)(I)
Interstate Transport State Implementation Plan Submissions for the
2015 Ozone National Ambient Air Quality Standards, October 19, 2018
(``October 2018 memorandum''), available in Docket No. EPA-HQ-OAR-
2021-0663 for this action or at https://www.epa.gov/airmarkets/memo-and-supplemental-information-regarding-interstate-transport-sips-2015-ozone-naaqs.
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Since the release of the modeling data shared in the March 2018
memorandum, EPA performed updated modeling using a 2016-based emissions
modeling platform (i.e., 2016v1). This emissions platform was developed
under the EPA/Multi-Jurisdictional Organization (MJO)/state
collaborative project.\14\ This collaborative project was a multi-year
joint effort by EPA, MJOs, and states to develop a new, more recent
emissions platform for use by EPA and states in regulatory modeling as
an improvement over the dated 2011-based platform that EPA had used to
project ozone design values and contribution data provided in the 2017
and 2018 memoranda. EPA used the 2016v1 emissions to project ozone
design values and contributions for 2023. On October 30, 2020, in the
Notice of Proposed Rulemaking for the Revised CSAPR Update, EPA
released and accepted public comment on 2023 modeling that used the
2016v1 emissions platform.\15\ Although the Revised CSAPR Update
addressed transport for the 2008 ozone NAAQS, the projected design
values and contributions from the 2016v1 platform are also useful for
identifying downwind ozone problems and linkages with respect to the
2015 8-hour ozone NAAQS.\16\
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\14\ The results of this modeling, as well as the underlying
modeling files, are included in Docket No. EPA-HQ-OAR-2021-0663.
\15\ See 85 FR 68964, 68981 (October 30, 2020).
\16\ See the Air Quality Modeling Technical Support Document for
the Final Revised Cross-State Air Pollution Rule Update, included in
Docket No. EPA-HQ-OAR-2021-0663.
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Following the Revised CSAPR Update final rule, EPA made further
updates to the 2016 emissions platform to include mobile emissions from
EPA's Motor Vehicle Emission Simulator (MOVES) model \17\ and updated
emissions projections for electric generating units (EGUs) that reflect
the emissions reductions from the Revised CSAPR Update, recent
information on plant closures, and other sector trends. The construct
of the updated emissions platform, 2016v2, is described in the
Preparation of Emissions Inventories for the 2016v2 North American
Emissions Modeling Platform technical support document (TSD) for this
proposed rule and is included in Docket No. EPA-HQ-OAR-2021-0663. EPA
performed air quality modeling of the 2016v2 emissions using the most
recent public release version of the Comprehensive Air Quality Modeling
with Extensions (CAMx) photochemical modeling,
[[Page 9501]]
version 7.10.\18\ EPA proposes to primarily rely on modeling based on
the updated and newly available 2016v2 emissions platform in evaluating
these submissions with respect to Steps 1 and 2 of the 4-step
interstate transport framework. By using the updated modeling results,
EPA is using the most current and technically appropriate information
for this proposed rulemaking. Section III of this notice and the Air
Quality Modeling TSD included in Docket No. EPA-HQ-OAR-2021-0663 for
this proposal contain additional detail on the modeling performed using
the 2016v2 emissions modeling.
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\17\ Additional details and documentation related to the MOVES3
model can be found at https://www.epa.gov/moves/latest-version-motor-vehicle-emission-simulator-moves.
\18\ Ramboll Environment and Health, January 2021, www.camx.com.
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In this notice, EPA is accepting public comment on this updated
2023 modeling, which uses the 2016v2 emissions platform. Details on the
air quality modeling and the methods for projecting design values and
determining contributions in 2023 are described in the Air Quality
Modeling TSD for 2015 8-hour Ozone NAAQS Transport SIP Proposed
Actions. Comments on EPA's air quality modeling should be submitted in
Docket No. EPA-R04-OAR-2021-0841. Comments are not being accepted in
Docket No. EPA-HQ-OAR-2021-0663.
States may have chosen to rely on the results of EPA modeling and/
or alternative modeling performed by states or Multi-Jurisdictional
Organizations (MJOs) to evaluate downwind air quality problems and
contributions as part of their submissions. In section III, EPA
evaluates how Kentucky used air quality modeling information in its
submission.
D. EPA's Approach to Evaluating Interstate Transport SIPs for the 2015
8-Hour Ozone NAAQS
EPA proposes to apply a consistent set of policy judgments across
all states for purposes of evaluating interstate transport obligations
and the approvability of interstate transport SIP submittals for the
2015 8-hour ozone NAAQS. These policy judgments reflect consistency
with relevant case law and past Agency practice as reflected in CSAPR
and related rulemakings. Nationwide consistency in approach is
particularly important in the context of interstate ozone transport,
which is a regional-scale pollution problem involving many smaller
contributors. Effective policy solutions to the problem of interstate
ozone transport going back to the NOX SIP Call have
necessitated the application of a uniform framework of policy judgments
in order to ensure an ``efficient and equitable'' approach. See EME
Homer City Generation, LP v. EPA, 572 U.S. 489, 519 (2014).
In the March, August, and October 2018 memoranda, EPA recognized
that states may be able to establish alternative approaches to
addressing their interstate transport obligations for the 2015 8-hour
ozone NAAQS that vary from a nationally uniform framework. EPA
emphasized in these memoranda, however, that such alternative
approaches must be technically justified and appropriate in light of
the facts and circumstances of each particular state's submittal. In
general, EPA continues to believe that deviation from a nationally
consistent approach to ozone transport must be substantially justified
and have a well-documented technical basis that is consistent with
relevant case law. Where states submitted SIPs that rely on any such
potential concepts as may have been identified or suggested in the
past, EPA will evaluate whether the state adequately justified the
technical and legal basis for doing so.
EPA notes that certain potential concepts included in an attachment
to the March 2018 memorandum require unique consideration, and these
ideas do not constitute Agency guidance with respect to transport
obligations for the 2015 8-hour ozone NAAQS. Attachment A to the March
2018 memorandum identified a ``Preliminary List of Potential
Flexibilities'' that could potentially inform SIP development.\19\
However, EPA made clear in that attachment that the list of ideas were
not suggestions endorsed by the Agency but rather ``comments provided
in various forums'' on which EPA sought ``feedback from interested
stakeholders.'' \20\ Further, Attachment A stated, ``EPA is not at this
time making any determination that the ideas discussed below are
consistent with the requirements of the CAA, nor [is EPA] specifically
recommending that states use these approaches.'' \21\ Attachment A to
the March 2018 memorandum, therefore, does not constitute agency
guidance, but was intended to generate further discussion around
potential approaches to addressing ozone transport among interested
stakeholders. To the extent states sought to develop or rely on these
ideas in support of their SIP submittals, EPA will thoroughly review
the technical and legal justifications for doing so.
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\19\ March 2018 memorandum, Attachment A.
\20\ Id. at A-1.
\21\ Id.
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The remainder of this section describes EPA's proposed framework
with respect to analytic year, definition of nonattainment and
maintenance receptors, selection of contribution threshold, and
multifactor control strategy assessment.
1. Selection of Analytic Year
In general, the states and EPA must implement the interstate
transport provision in a manner ``consistent with the provisions of
[title I of the CAA].'' See CAA section 110(a)(2)(D)(i). This requires,
among other things, that these obligations are addressed consistently
with the timeframes for downwind areas to meet their CAA obligations.
With respect to ozone NAAQS, under CAA section 181(a), this means
obligations must be addressed ``as expeditiously as practicable'' and
no later than the schedule of attainment dates provided in CAA section
181(a)(1).\22\ Several D.C. Circuit court decisions address the issue
of the relevant analytic year for the purposes of evaluating ozone
transport air-quality problems. On September 13, 2019, the D.C. Circuit
issued a decision in Wisconsin v. EPA, remanding the CSAPR Update to
the extent that it failed to require upwind states to eliminate their
significant contribution by the next applicable attainment date by
which downwind states must come into compliance with the NAAQS, as
established under CAA section 181(a). See 938 F.3d 303, 313.
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\22\ For attainment dates for the 2015 8-hour ozone NAAQS, refer
to CAA section 181(a), 40 CFR 51.1303, and Additional Air Quality
Designations for the 2015 Ozone National Ambient Air Quality
Standards, 83 FR 25776 (June 4, 2018, effective August 3, 2018).
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On May 19, 2020, the D.C. Circuit issued a decision in Maryland v.
EPA that cited the Wisconsin decision in holding that EPA must assess
the impact of interstate transport on air quality at the next downwind
attainment date, including Marginal area attainment dates, in
evaluating the basis for EPA's denial of a petition under CAA section
126(b). Maryland v. EPA, 958 F.3d 1185, 1203-04 (D.C. Cir. 2020). The
court noted that ``section 126(b) incorporates the Good Neighbor
Provision,'' and, therefore, ``EPA must find a violation [of section
126] if an upwind source will significantly contribute to downwind
nonattainment at the next downwind attainment deadline. Therefore, the
agency must evaluate downwind air quality at that deadline, not at some
later date.'' Id. at 1204 (emphasis added). EPA interprets the court's
holding in Maryland as requiring the states and the Agency, under the
good neighbor provision, to assess downwind air quality as
expeditiously as practicable and no later than the next
[[Page 9502]]
applicable attainment date,\23\ which is now the Moderate area
attainment date under CAA section 181 for ozone nonattainment. The
Moderate area attainment date for the 2015 8-hour ozone NAAQS is August
3, 2024.\24\ EPA believes that 2023 is now the appropriate year for
analysis of interstate transport obligations for the 2015 8-hour ozone
NAAQS, because the 2023 ozone season is the last relevant ozone season
during which achieved emissions reductions in linked upwind states
could assist downwind states with meeting the August 3, 2024, Moderate
area attainment date for the 2015 8-hour ozone NAAQS.
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\23\ EPA notes that the court in Maryland did not have occasion
to evaluate circumstances in which EPA may determine that an upwind
linkage to a downwind air quality problem exists at Steps 1 and 2 of
the interstate transport framework by a particular attainment date,
but for reasons of impossibility or profound uncertainty the Agency
is unable to mandate upwind pollution controls by that date. See
Wisconsin, 938 F.3d at 320. The D.C. Circuit noted in Wisconsin that
upon a sufficient showing, these circumstances may warrant
flexibility in effectuating the purpose of the interstate transport
provision.
\24\ See CAA section 181(a); 40 CFR 51.1303; Additional Air
Quality Designations for the 2015 Ozone National Ambient Air Quality
Standards, 83 FR 25776 (June 4, 2018, effective August 3, 2018).
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EPA recognizes that the attainment date for nonattainment areas
classified as Marginal for the 2015 8-hour ozone NAAQS was August 3,
2021. Under the Maryland holding, any necessary emissions reductions to
satisfy interstate transport obligations should have been implemented
by no later than this date. At the time of the statutory deadline to
submit interstate transport SIPs (October 1, 2018), many states relied
upon EPA modeling of the year 2023, and no state provided an
alternative analysis using a 2021 analytic year (or the prior 2020
ozone season). However, EPA must act on SIP submittals using the
information available at the time it takes such action. In this
circumstance, EPA does not believe it would be appropriate to evaluate
states' obligations under CAA section 110(a)(2)(D)(i)(I) as of an
attainment date that is wholly in the past, because the Agency
interprets the interstate transport provision as forward looking. See
86 FR 23054, 23074; see also Wisconsin, 938 F.3d at 322. Consequently,
in this proposal EPA will use the analytical year of 2023 to evaluate
each state's CAA section 110(a)(2)(D)(i)(I) SIP submission with respect
to the 2015 8-hour ozone NAAQS.
2. Step 1 of the 4-Step Interstate Transport Framework
In Step 1, EPA identifies monitoring sites that are projected to
have problems attaining and/or maintaining the NAAQS in the 2023
analytic year. Where EPA's analysis shows that a site does not fall
under the definition of a nonattainment or maintenance receptor, that
site is excluded from further analysis under EPA's 4-step interstate
transport framework. For sites that are identified as a nonattainment
or maintenance receptor in 2023, EPA proceeds to the next step of the
4-step interstate transport framework by identifying the upwind state's
contribution to those receptors.
EPA's approach to identifying ozone nonattainment and maintenance
receptors in this action is consistent with the approach used in
previous transport rulemakings. EPA's approach gives independent
consideration to both the ``contribute significantly to nonattainment''
and the ``interfere with maintenance'' prongs of CAA section
110(a)(2)(D)(i)(I), consistent with the D.C. Circuit's direction in
North Carolina v. EPA.\25\
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\25\ See North Carolina v. EPA, 531 F.3d 896, 910-11 (D.C. Cir.
2008) (holding that EPA must give ``independent significance'' to
each prong of CAA section 110(a)(2)(D)(i)(I)).
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For the purpose of this proposal, EPA identifies nonattainment
receptors as those monitoring sites that are projected to have average
design values that exceed the NAAQS and that are also measuring
nonattainment based on the most recent monitored design values. This
approach is consistent with prior transport rulemakings, such as the
CSAPR Update, where EPA defined nonattainment receptors as those areas
that both currently measure nonattainment and that EPA projects will be
in nonattainment in the future analytic year (i.e., 2023).\26\
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\26\ See 81 FR 74504 (October 26, 2016). This same concept,
relying on both current monitoring data and modeling to define
nonattainment receptor, was also applied in CAIR. See 70 FR at
25241, 25249 (January 14, 2005); see also North Carolina, 531 F.3d
at 913-14 (affirming as reasonable EPA's approach to defining
nonattainment in CAIR).
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In addition, in this proposal, EPA identifies a receptor to be a
``maintenance'' receptor for purposes of defining interference with
maintenance, consistent with the method used in CSAPR and upheld by the
D.C. Circuit in EME Homer City Generation, L.P. v. EPA, 795 F.3d 118,
136 (D.C. Cir. 2015).\27\ Specifically, EPA identified maintenance
receptors as those receptors that would have difficulty maintaining the
relevant NAAQS in a scenario that takes into account historical
variability in air quality at that receptor. The variability in air
quality was determined by evaluating the ``maximum'' future design
value at each receptor based on a projection of the maximum measured
design value over the relevant period. EPA interprets the projected
maximum future design value to be a potential future air quality
outcome consistent with the meteorology that yielded maximum measured
concentrations in the ambient data set analyzed for that receptor
(i.e., ozone conducive meteorology). EPA also recognizes that
previously experienced meteorological conditions (e.g., dominant wind
direction, temperatures, air mass patterns) promoting ozone formation
that led to maximum concentrations in the measured data may reoccur in
the future. The maximum design value gives a reasonable projection of
future air quality at the receptor under a scenario in which such
conditions do, in fact, reoccur. The projected maximum design value is
used to identify upwind emissions that, under those circumstances,
could interfere with the downwind area's ability to maintain the NAAQS.
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\27\ See 76 FR 48208 (August 8, 2011). The CSAPR Update and
Revised CSAPR Update also used this approach. See 81 FR 74504
(October 26, 2016) and 86 FR 23054 (April 30, 2021).
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Recognizing that nonattainment receptors are also, by definition,
maintenance receptors, EPA often uses the term ``maintenance-only'' to
refer to those receptors that are not nonattainment receptors.
Consistent with the concepts for maintenance receptors, as described
above, EPA identifies ``maintenance-only'' receptors as those
monitoring sites that have projected average design values above the
level of the applicable NAAQS, but that are not currently measuring
nonattainment based on the most recent official design values. In
addition, those monitoring sites with projected average design values
below the NAAQS, but with projected maximum design values above the
NAAQS are also identified as ``maintenance-only'' receptors, even if
they are currently measuring nonattainment based on the most recent
official design values.
3. Step 2 of the 4-Step Interstate Transport Framework
In Step 2, EPA quantifies the contribution of each upwind state to
each receptor in the 2023 analytic year. The contribution metric used
in Step 2 is defined as the average impact from each state to each
receptor on the days with the highest ozone concentrations at the
receptor based on the 2023 modeling. If a state's contribution value
does not equal or exceed the threshold of 1 percent of the NAAQS (i.e.,
0.70 ppb for the 2015 8-hour ozone NAAQS), the upwind state is not
``linked'' to a
[[Page 9503]]
downwind air quality problem, and EPA, therefore, concludes that the
state does not significantly contribute to nonattainment or interfere
with maintenance of the NAAQS in the downwind states. However, if a
state's contribution equals or exceeds the 1 percent threshold, the
state's emissions are further evaluated in Step 3, considering both air
quality and cost as part of a multi-factor analysis, to determine what,
if any, emissions might be deemed ``significant'' and, thus, must be
eliminated under CAA section 110(a)(2)(D)(i)(I).
EPA is proposing to rely in the first instance on the 1 percent
threshold for the purpose of evaluating a state's contribution to
nonattainment or maintenance of the 2015 8-hour ozone NAAQS (i.e., 0.70
ppb) at downwind receptors. This is consistent with the Step 2 approach
that EPA applied in CSAPR for the 1997 ozone NAAQS, which has
subsequently been applied in the CSAPR Update when evaluating
interstate transport obligations for the 2008 ozone NAAQS. EPA
continues to find 1 percent to be an appropriate threshold. For ozone,
as EPA found in the CAIR, CSAPR, and the CSAPR Update, a portion of the
nonattainment problems from anthropogenic sources in the U.S. result
from the combined impact of relatively small contributions from many
upwind states, along with contributions from in-state sources and, in
some cases, substantially larger contributions from a subset of
particular upwind states. EPA's analysis shows that much of the ozone
transport problem being analyzed in this proposed rule is still the
result of the collective impacts of contributions from many upwind
states. Therefore, application of a consistent contribution threshold
is necessary to identify those upwind states that should have
responsibility for addressing their contribution to the downwind
nonattainment and maintenance problems to which they collectively
contribute. Continuing to use 1 percent of the NAAQS as the screening
metric to evaluate collective contribution from many upwind states also
allows EPA (and states) to apply a consistent framework to evaluate
interstate emissions transport under the interstate transport provision
from one NAAQS to the next. See 81 FR at 74518 (August 8, 2011); see
also 86 FR at 23085 (April 30, 2021) (reviewing and explaining
rationale from CSAPR, 76 FR at 48237-38 (August 8, 2011), for selection
of 1 percent threshold).
EPA's August 2018 memorandum recognized that in certain
circumstances, a state may be able to establish that an alternative
contribution threshold of 1 ppb is justifiable. Where a state relies on
this alternative threshold, and where that state determined that it was
not linked at Step 2 using the alternative threshold, EPA will evaluate
whether the state provided a technically sound assessment of the
appropriateness of using this alternative threshold based on the facts
and circumstances underlying its application in the particular SIP
submission.
4. Step 3 of the 4-Step Interstate Transport Framework
Consistent with EPA's longstanding approach to eliminating
significant contribution or interference with maintenance, at Step 3,
states linked at Steps 1 and 2 are generally expected to prepare a
multifactor assessment of potential emissions controls. EPA's analysis
at Step 3 in prior Federal actions addressing interstate transport
requirements has primarily focused on an evaluation of cost-
effectiveness of potential emissions controls (on a marginal cost-per-
ton basis), the total emissions reductions that may be achieved by
requiring such controls (if applied across all linked upwind states),
and an evaluation of the air quality impacts such emissions reductions
would have on the downwind receptors to which a state is linked; other
factors may potentially be relevant if adequately supported. In
general, where EPA's or alternative air quality and contribution
modeling establishes that a state is linked at Steps 1 and 2, it will
be insufficient at Step 3 for a state merely to point to its existing
rules requiring control measures as a basis for approval. In general,
the emissions-reducing effects of all existing emissions control
requirements are already reflected in the air quality results of the
modeling for Steps 1 and 2. If the state is shown to still be linked to
one or more downwind receptor(s), states must provide a well-documented
evaluation determining whether their emissions constitute significant
contribution or interference with maintenance by evaluating additional
available control opportunities by preparing a multifactor assessment.
While EPA has not prescribed a particular method for this assessment,
EPA expects states at a minimum to present a sufficient technical
evaluation. This would typically include information on emissions
sources, applicable control technologies, emissions reductions, costs,
cost effectiveness, and downwind air quality impacts of the estimated
reductions, before concluding that no additional emissions controls
should be required.\28\
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\28\ As examples of general approaches for how such an analysis
could be conducted for their sources, states could look to the CSAPR
Update, 81 FR 74504, 74539-51; CSAPR, 76 FR 48208, 48246-63; CAIR,
70 FR 25162, 25195-229; or the NOX SIP Call, 63 FR 57356,
57399-405. See also Revised CSAPR Update, 86 FR 23054, 23086-23116.
Consistently across these rulemakings, EPA has developed emissions
inventories, analyzed different levels of control stringency at
different cost thresholds, and assessed resulting downwind air
quality improvements.
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5. Step 4 of the 4-Step Interstate Transport Framework
At Step 4, states (or EPA) develop permanent and federally
enforceable control strategies to achieve the emissions reductions
determined to be necessary at Step 3 to eliminate significant
contribution to nonattainment or interference with maintenance of the
NAAQS. For a state linked at Steps 1 and 2 to rely on an emissions
control measure at Step 3 to address its interstate transport
obligations, that measure must be included in the state's
implementation plan so that it is permanent and federally enforceable.
See CAA section 110(a)(2)(D) (``Each such [SIP] shall . . . contain
adequate provisions. . . .''). See also CAA section 110(a)(2)(A);
Committee for a Better Arvin v. EPA, 786 F.3d 1169, 1175-76 (9th Cir.
2015) (holding that measures relied on by a state to meet CAA
requirements must be included in the SIP).
II. Summary of Kentucky's 2015 8-Hour Ozone Interstate Transport SIP
Submission
On January 11, 2019, Kentucky submitted a SIP revision, a portion
of which addressed the CAA section 110(a)(2)(D)(i)(I) interstate
transport requirements for the 2015 8-hour ozone NAAQS. The
Commonwealth's SIP submission provided Kentucky's analysis of its
impact to downwind states and concluded that the Commonwealth had met
the requirements of CAA section l10(a)(2)(D)(i)(I) (i.e., prongs 1 and
2) because Kentucky's SIP contains adequate provisions to prevent
sources and other types of emissions activities within the Commonwealth
from significantly contributing to nonattainment, or interfering with
the maintenance, of downwind states with respect to the 2015 8-hour
ozone NAAQS.
The Commonwealth's submission relied on the results of EPA's
modeling of the year 2023, contained in the March 2018 memorandum, to
identify downwind nonattainment and
[[Page 9504]]
maintenance receptors that may be ``linked'' to emissions from sources
in Kentucky (which correlates to Step 1 of the 4-step framework).\29\
The March 2018 modeling indicates that the Commonwealth was linked to
four nonattainment receptors and one maintenance monitor above 1% of
the NAAQS. The largest impact from Kentucky sources on any downwind
nonattainment receptor in the East was projected to be 0.89 ppb at the
Fairfield County, Connecticut (ID: 90013007) site. The other
nonattainment receptors to which Kentucky was linked are: a second site
in Fairfield County (ID: 90019003); Milwaukee, Wisconsin (ID:
550790085); and Sheboygan, Wisconsin (ID: 551170006). The impact from
Kentucky sources on the one downwind maintenance-only receptor to which
it was linked in that modeling was 1.52 ppb at the Harford County,
Maryland monitor (ID: 240251001).
---------------------------------------------------------------------------
\29\ EPA notes that Kentucky's SIP submission is not organized
around EPA's 4-step framework for assessing good neighbor
obligations, but EPA summarizes the submission using that framework
for clarity here.
---------------------------------------------------------------------------
The Commonwealth reviewed EPA's August 2018 memorandum as it
related to the use of a potential alternative contribution threshold of
1 ppb and agreed that use of a 1 ppb contribution threshold is
comparable to the amount of collective contribution captured using a
threshold equivalent to 1 percent of the NAAQS. Based on the March 2018
modeling and application of a 1 ppb alternative contribution threshold,
the Commonwealth found that it would not be linked as a significant
contributor to the four nonattainment receptors in Connecticut and
Wisconsin (which correlates to EPA's Step 2), and therefore concluded
that no further controls were required to address its contribution to
those four receptors. Thus, the Commonwealth concluded that Kentucky's
SIP contains adequate provisions to prevent sources and other types of
emissions activities within the Commonwealth from contributing
significantly to nonattainment in any other state (i.e., ``prong 1'' of
CAA section l10(a)(2)(D)(i)(I)) for the 2015 8-hour ozone NAAQS.
After application of the 1 ppb contribution threshold, Kentucky
remained linked to the downwind maintenance-only receptor at Harford
County, Maryland (ID: 240251001) because the Commonwealth's
contribution of 1.52 ppb to this receptor was greater than the 1 ppb
alternative threshold. Kentucky's SIP submission asserted that the
amount of NOX emission reductions required for an upwind
state should not be the same for a monitor that is already attaining
the NAAQS as they are for a nonattainment monitor. The Commonwealth
further asserted that local controls should be implemented before
requiring upwind states to control their sources. Thus, Kentucky
concluded that no further reductions other than on-the-books and on-
the-way measures are required to address the Commonwealth's interstate
transport obligation to eliminate its contribution to the Harford
County, Maryland maintenance receptor.
In addition, Kentucky provided information intended to demonstrate
that Kentucky's SIP contains adequate provisions to prevent sources and
other types of emissions activities within the Commonwealth from
significantly contributing to nonattainment, or interfering with the
maintenance, of downwind states with respect to the 2015 8-hour ozone
NAAQS, and thus, no additional emissions reductions from Kentucky are
necessary. Specifically, Kentucky listed existing state, SIP-approved
regulations and Federal programs for sources in the Commonwealth that
it concluded address the requirements of CAA 110(a)(2)(D)(i)(I) for the
2015 8-hour ozone NAAQS.\30\ Kentucky provided more detailed analyses
related to several specific topics, which are summarized in sections
below.
---------------------------------------------------------------------------
\30\ See Kentucky's January 11, 2019, SIP submission, at pages
20 through 30 for the list of state, SIP-approved regulations and
Federal programs identified by Kentucky.
---------------------------------------------------------------------------
The Commonwealth also included documents attached as appendices to
its submittal. The March 2018 memorandum and the August 2018 memorandum
were attached at appendices A and B, respectively.\31\ As Appendix C,
the Commonwealth appended several documents developed and/or submitted
by the Midwest Ozone Group (a consortium of upwind industries with
emitting facilities).\32\ This included a modeling analysis developed
by Alpine Geophysics titled ``Good Neighbor Modeling Technical Support
Document for the 8-hour Ozone State Implementation Plans,'' dated June
2018 (Alpine TSD). The Alpine TSD contains alternative modeling of 2023
performed by Alpine Geophysics sponsored by MOG, as well as additional
policy suggestions that MOG suggested states could consider in
developing good neighbor SIP submissions (see section 9 of the Alpine
TSD).\33\ The Alpine TSD also appended a separate set of MOG comments
on EPA's March 2018 memorandum.\34\ These comments and Alpine's
modeling analysis were further summarized in a Microsoft PowerPoint
Presentation titled ``MOG's Preview of 2015 Ozone NAAQS Good Neighbor
SIPs.'' EPA also summarizes the materials developed by MOG that the
Commonwealth included as Appendix C to its submittal, although it is
unclear that Kentucky intended to rely on all aspects of these
materials.
---------------------------------------------------------------------------
\31\ See the following Appendices to Kentucky's January 11,
2019, submission: Appendix A--Information on the Interstate
Transport State Implementation Plan Submissions for the 2015 Ozone
National Ambient Air Quality Standards under Clean Air Act Section
110(a)(2)(D)(i)(I), March 27, 2018 (``March 2018 memorandum'');
Appendix B--Analysis of Contribution Thresholds for Use in Clean Air
Act Section 110(a)(2)(D)(i)(I) Interstate Transport State
Implementation Plan Submissions for the 2015 Ozone National Ambient
Air Quality Standards, August 31, 2018; and Appendix D--Public
Hearing & Statement of Consideration.
\32\ See Appendix C to Kentucky's January 11, 2019, submission--
Midwest Ozone Group Technical Support Document: ``Good Neighbor
Modeling Technical Support Document for 8-Hour Ozone Implementation
Plans.''
\33\ It is unclear whether Kentucky intends to rely on all of
the data and policy approaches in Appendix C as included in its
submittal, or if these documents were appended solely to support
specific policy and technical arguments relied on by Kentucky in its
submittal.
\34\ See the following Appendices to Appendix C--Midwest Ozone
Group Technical Support Document: ``Good Neighbor Modeling Technical
Support Document for 8-Hour Ozone Implementation Plans of Kentucky's
January 11, 2019: Appendix A--4km Modeling Results for Mid-Atlantic
and Lake Michigan Domains Compared to EPA 12 km ``No Water'' Design
Value Calculations from March 2018 Memorandum; Appendix B--Midwest
Ozone Group Comments on EPA's March 27, 2018 Memorandum Entitled
``Information on the Interstate Transport State Implementation Plan
Submissions for the 2015 Ozone National Ambient Air Quality
Standards under Clean Air Act Section 110(a)(2)(D)(i)(I); Appendix
C--Presentation--Midwest Ozone Group Preview of 2015 Ozone NAAQS
Good Neighbor SIPs.
---------------------------------------------------------------------------
A. Information Related to Emission Trends From Kentucky Sources
With respect to ozone precursors emitted from Kentucky sources,
Kentucky focused its analysis on NOX emissions, as it found
that ozone is far more sensitive to NOX emissions than VOC
emissions in the Southeastern United States and that controlling
NOX emissions is a more effective strategy in reducing
ozone. Kentucky reviewed NOX emissions trends in the
Commonwealth, comparing annual NOX emissions from 2008 to
2016, finding that NOX emissions in Kentucky have
significantly decreased since 2008. The Commonwealth asserted that it
has significantly lowered NOX emissions between 2008 and
2017 \35\ and contended that planned shutdowns and
[[Page 9505]]
conversion to natural gas, along with the implementation of Federal and
State programs, ensure Kentucky's emissions will continue to decrease.
Based on the 2014 national emission inventory (NEI), Kentucky indicated
that the major contributor of NOX emissions in the
Commonwealth are point sources, mainly comprised of electric generating
units (EGUs).
---------------------------------------------------------------------------
\35\ Table 2 in Kentucky's SIP provides historic annual
NOX emissions data for point sources in the state from
2008 through 2016, however, the associated graph at Chart 1
indicates annual NOX emissions from 2008 through 2017.
---------------------------------------------------------------------------
Kentucky asserted that NOX emissions from EGUs in the
Commonwealth have decreased and would continue to decrease based, in
part, on the implementation of CAIR, CSAPR, and the CSAPR Update, as
well as retirements of several EGUs in the Commonwealth. The
Commonwealth compared Kentucky's NOX ozone season
allocations to actual EGU emissions in the Commonwealth, concluding
that Kentucky's NOX ozone season budgets have decreased
since the implementation of CSAPR and the CSAPR Update and actual ozone
season NOX emissions are significantly lower than the
trading program budgets.\36\ The SIP submission summarized coal-fired
unit retirements, shutdowns, and repowering from 2015 through 2017 as
well as on-the-way reductions from natural gas conversions and
retirements from 2017 through 2023.\37\ Kentucky stated that it
expected emissions will continue to decline in the future due to
continued implementation of CSAPR, the CSAPR Update, and scheduled
shutdowns, fuel switches, and retirements of facilities in the
Commonwealth.
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\36\ Kentucky's SIP acknowledged that the CSAPR trading program
does not address interstate transport for the 2015 standard but
nonetheless provides NOX emission reductions.
\37\ See Kentucky's January 11, 2019, submittal located in
Docket No. EPA-R04-OAR-2021-0841, at pages 32-33 for discussion on
implementation of CSAPR, the CSAPR Update, EGU retirements, and EGU
fuel switches.
---------------------------------------------------------------------------
B. Information Related to Connecticut Monitors Provided by Kentucky
EPA's March 2018 modeling showed Kentucky linked to the two
receptors located in Fairfield County, Connecticut, which is part of
the New York-Northern New Jersey-Long Island, NY-NJ-CT (New York Metro
Area) core based statistical area (CBSA).\38\ Kentucky applied an
alternative contribution threshold of 1 ppb, and thus determined that
Kentucky was no longer linked to the Connecticut receptors. In
addition, Kentucky provided information intended to demonstrate that
emissions from local sources in the area surrounding the monitors
contribute significantly to the continued nonattainment issues, and
thus, that local controls should be implemented before requesting
upwind states to control facilities.
---------------------------------------------------------------------------
\38\ EPA's designations for the 2015 8-hour ozone standard
divided the state into two areas, Greater Connecticut, CT, with a
marginal classification, and New York-Northern New Jersey-Long
Island, NY-NJ-CT (New York Metro Area), with a moderate
classification. See https://www.epa.gov/ozone-designations/additional-designations-2015-ozone-standards.
---------------------------------------------------------------------------
In particular, Kentucky's SIP submission claims that the Westport
Sherwood, Fairfield, Connecticut (ID: 90019003) and Stratford Point
Lighthouse, Fairfield County (ID: 90013007) monitors are located less
than three miles from the I-95 interstate highway corridor and over 500
miles from Kentucky. Kentucky asserted these monitors have a consistent
pattern of violating the 2015 8-hour ozone NAAQS from 2007 to 2016.
Kentucky also pointed out that it is not linked in the modeling to two
other nonattainment receptors (the Greenwich Point Park and Criscuolo
Park monitoring sites) that are in relatively close proximity to the
Westport and Stratford monitors. Kentucky compared the distances
between these sites with the distances of the sites to Kentucky's
nearest border.
Kentucky's SIP submission also provided information related to the
New York Metro Area, citing the 2014 NEI to state that the on-road
source sector contributed the highest amount of NOX
emissions and that the nonpoint source sector contributed the highest
amount of VOC emissions in that area. The Commonwealth further provided
information about high vehicle miles traveled (VMT) and commuting
patterns in the New York Metro Area, as well as information regarding
violating monitors along the I-95 corridor and outlying monitors that
show attainment.
Additionally, Kentucky's SIP submission includes Hybrid Single
Particle Lagrangian Integrated Trajectory (HYSPLIT) model back
trajectory analysis to the two Connecticut receptors,\39\ asserting
that the HYSPLIT analysis indicates that the monitors are downwind of
nonattainment areas in New York, New Jersey, Pennsylvania, and
Maryland. The Commonwealth also asserted there is a consistent pattern
of violating monitors located along the I-95 corridor. In addition,
Kentucky asserted that pollutants are trapped in the marine boundary
layer and then transported inland to coastal Connecticut receptors due
to conditions on Long Island Sound.
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\39\ According to Kentucky, the HYSPLIT analysis were generated
using EPA's 2015 Ozone Designation Mapping Tool, available at
https://www.epa.gov/ozone-designations/ozone-designations-guidance-
and-
data#:~:text=The%20ozone%20designations%20mapping%20tool,for%20the%20
2015%20Ozone%20NAAQS.
---------------------------------------------------------------------------
The Commonwealth's SIP submission also discussed point sources in
the New York Metro Area, providing information regarding the largest
point sources in that area. In addition, Kentucky provided
NOX and VOC emission information for 13 counties in the New
York Metro Area that have NOX and VOC emission totals above
10,000 tpy, finding that three counties that surround Fairfield County
(Suffolk, Queens, and Nassau Counties) had the highest NOX
emissions.
Kentucky further evaluated high electric demand days in New York,
discussing a New York Department of Environmental Conservation (NYDEC)
determination that peaking units operating on peak electricity demand
days are a major contributor of NOX (particularly units
installed before 1987), and that such units can contribute 4.8 ppb of
ozone on high ozone days.\40\ Kentucky concluded NOX
emission reductions from these EGUs point sources would have a
significant impact on ozone levels in the New York Metro Area.
---------------------------------------------------------------------------
\40\ Kentucky references NYDEC emission analysis entitled
``Background, High Electric Demand Day (HEDD) Initiative'', New York
Department of Environmental Conservation.
---------------------------------------------------------------------------
C. Information Related to the Harford, Maryland Monitor Provided by
Kentucky
Kentucky acknowledged that EPA's March 27, 2018 modeling shows the
potential for Kentucky emissions to significantly contribute to the
Edgewood, Harford County, Maryland (ID: 240251001) maintenance-only
monitor (Edgewood monitor) in 2023. However, Kentucky provided air
quality data designed to demonstrate that emissions from local sources
in the area surrounding the monitors contribute significantly to the
continued air quality issues and concluded that there are local
controls that should be implemented before requesting upwind states to
control facilities.
Kentucky provided additional information with respect to the
Edgewood Monitor, which is located 3 miles from the I-95 corridor and
approximately 350 miles from Kentucky. Kentucky provided data to show
that the Edgewood monitor consistently violated the 2015 8-hour ozone
standard from 2007 to 2016. Kentucky also provided information related
to other nonattainment monitors located in Baltimore County and Harford
County.
The Commonwealth's SIP submission provided data related to the
Baltimore-
[[Page 9506]]
Columbia-Towson, MD CBSA (Baltimore Area), citing to the 2014 NEI to
state that the on-road source sector contributed the highest amount of
NOX emissions and that the nonpoint source sector
contributed the highest amount of VOC emissions in that area. Kentucky
further provided information about VMTs and commuting patterns in the
Baltimore Area, as well as information regarding violating monitors
along the I-95 corridor and outlying monitors that show attainment. The
SIP submission asserted that local mobile emissions are a key
contributor to the Edgewood monitor, which is also located in close
proximity to the 1-95 corridor. Kentucky further cited to a
presentation and remarks by Maryland officials, discussing programs to
reduce emissions from local sources, specifically focusing on mobile
source NOX reduction programs.
Kentucky cited a 2010 case study in the Chesapeake Bay that
suggests the transport of pollution from nearby urban areas accumulates
over the Bay and becomes stagnant, creating a bay breeze which is
pushed by southerly winds northward towards the Edgewood monitor.
Additionally, Kentucky's SIP submission also provided HYSPLIT model
back trajectory analysis to the Edgewood receptor,\41\ asserting that
the HYSPLIT indicates that the monitors are downwind of nonattainment
areas in Baltimore County, Baltimore City, Arlington County, and the
District of Columbia. Kentucky also asserted that higher altitude
particles from the northwest of Baltimore combine with lower-level
particles from the south and southeast.
---------------------------------------------------------------------------
\41\ According to Kentucky, the HYSPLIT analysis were generated
using EPA's 2015 Ozone Designation Mapping Tool, available at
https://www.epa.gov/ozone-designations/ozone-designations-guidance-
and-
data#:~:text=The%20ozone%20designations%20mapping%20tool,for%20the%20
2015%20Ozone%20NAAQS.
---------------------------------------------------------------------------
Kentucky's submission used information on local mobile emissions
along the I-95 corridor and coastal air pollution formation and
accumulation along the Maryland coast to support its conclusion that
local air quality problems are the source of ozone violations at these
monitors.
Additionally, Kentucky asserted that the implementation of local
programs to reduce emissions should be sufficient for monitors in the
Maryland area to attain the 2015 8-hour ozone NAAQS. Kentucky cited
claims by MOG (appended to the submittal in Appendix C) that the
modeling in EPA's March 2018 memorandum does not account for additional
retirements, conversions, and modifications or emission control
programs expected to be implemented before 2023. Kentucky concluded
that because the Edgewood monitor is a maintenance receptor, the
Commonwealth believes that no further reductions from Kentucky sources
other than on-the-books controls should be required because maintenance
receptors should be treated differently than nonattainment receptors in
terms of upwind requirements. The Commonwealth also asserted that
states linked to maintenance receptors should be held to less stringent
standards of emissions reductions as compared to states linked to a
nonattainment receptor.
The Commonwealth also asserted that local emission controls should
be implemented before upwind states are required to control their
facilities, which is based on Kentucky's concurrence with statements
from MOG. The Commonwealth cited MOG's comments on local controls
stating: ``When an area is measuring nonattainment of a NAAQS, as is
the case with the areas linked to Kentucky, the CAA requires that the
effects and benefits of local controls on all source sectors be
considered first, prior to pursuing controls of sources in upwind
states.'' \42\ The Commonwealth concluded that the emissions reductions
resulting from on-the-books and on-the-way measures are adequate to
prohibit emissions within Kentucky from interfering with the
maintenance of downwind states with respect to the 2015 8-hour ozone
NAAQS.
---------------------------------------------------------------------------
\42\ Kentucky's SIP references MOG's comments that cite CAA
sections 107(a) and 110(a)(1).
---------------------------------------------------------------------------
D. Summary of Conclusions From Kentucky
In summary, based on Kentucky's reliance on the modeling results in
EPA's March 2018 memorandum, the Commonwealth found that emissions from
Kentucky sources were potentially linked to four nonattainment monitors
in Connecticut and Wisconsin and one maintenance receptor in Harford
County, Maryland. However, after utilizing a 1 ppb alternative
contribution threshold, the Commonwealth concluded that it was no
longer linked to the four nonattainment monitors, and thus, that the
Kentucky SIP contains adequate provisions to prevent sources and other
types of emissions activities within the State from contributing
significantly to nonattainment in any other state (i.e., ``prong 1'' of
CAA section 110(a)(2)(D)(i)(I)) for the 2015 8-hour ozone NAAQS.
Although modeling results indicated that Kentucky remained linked to
the maintenance-only receptor in Harford County, Maryland, even after
the application of the 1 ppb alternative threshold, Kentucky asserted
that states should not be required to apply the same degree of
reductions for maintenance receptors as nonattainment areas, and
determined that additional NOX emission reductions other
than those that are on-the-books or on-the-way are not required to
address its downwind contribution to that receptor. Kentucky further
provided an assessment of local sources in the vicinity of the
Connecticut and Maryland monitors and concluded that local
(particularly mobile) emissions, high VMTs and commuting patterns, and
weather patterns are the primary cause of violating monitors in these
areas. Therefore, Kentucky concluded that its SIP has adequate
provisions to prohibit emissions from interfering with maintenance in
another state (i.e., ``prong 2'' of CAA section 110(a)(2)(D)(i)(I))
with respect to the 2015 8-hour ozone NAAQS.
E. Summary of Midwest Ozone Group TSD Appended to Kentucky's Submittal
Kentucky attached several materials developed by MOG to its
submittal as Appendix C, which included a document titled `` `Good
Neighbor' Modeling Technical Support Document for 8-Hour Ozone State
Implementation Plans'' prepared by Alpine Geophysics.\43\ The Alpine
Geophysics document also attached the following documents: 4 kilometer
(km) modeling results for mid-Atlantic and Lake Michigan domains
compared to EPA 12 km ``No Water'' Design Value Calculations from March
2018 memorandum (Appendix A); MOG comments on EPA's March 2018
memorandum (Appendix B); and a Microsoft PowerPoint presentation from
MOG previewing 2015 8-hour ozone NAAQS good neighbor SIPs (Appendix C).
EPA notes a number of modeling results and technical and policy
arguments provided in the MOG attachments are not explicitly discussed
in Kentucky's SIP submission narrative. Therefore, it is unclear
whether Kentucky intended to rely on Alpine's modeling or MOG's policy
argument to support the Commonwealth's overall transport SIP
conclusions. To ensure review of all potentially relevant technical and
policy issues identified in Kentucky's SIP package, this section
summarizes key arguments presented in
[[Page 9507]]
Appendix C. However, in EPA's evaluation of the SIP submittal in
section III, EPA will differentiate between those positions clearly
adopted by the Commonwealth and those where it is unclear and therefore
a position espoused by MOG cannot be attributed to Kentucky.
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\43\ See Appendix C of Kentucky's January 11, 2019, transport
SIP submission.
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Appendix C included modeling results performed by Alpine Geophysics
as presented in the Alpine TSD. The Alpine modeling results identified
the Harford, Maryland receptor as a nonattainment receptor, with
Kentucky emissions contributing 2.07 ppb. In addition, the Alpine
modeling results identified Kentucky linkages above 1 percent to the
following maintenance-only receptors: Gloucester, New Jersey (ID:
340150002), with a Kentucky contribution of 1.69 ppb; Richmond, New
York (ID: 360850067), with a Kentucky contribution of 0.93; and
Philadelphia, Pennsylvania (ID: 421010024), with a Kentucky
contribution of 1.53. (While MOG asserts in separate comments that
emission reductions not accounted for in EPA's modeling suggests there
will be no receptors by 2023, this is not consistent with Alpine's
modeling.)
The Alpine TSD also evaluated additional approaches and
flexibilities that states could apply in SIP revisions, based on the
potential concepts provided in Appendix A of EPA's March 2018
memorandum.\44\ These included reliance on alterative modeling data,
evaluation of international contributions (both anthropogenic
contribution and as an additional percentage of boundary conditions),
alternate contribution thresholds, proportional control of upwind
emissions by level of upwind state contribution, and addressing
interference with maintenance obligations through use of 10-year
projections.
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\44\ See Section 9.0--Selected SIP Revision Approaches in
Appendix C--MOG's TSD of Kentucky's January 11, 2019 transport SIP
submission.
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MOG suggested states should be allowed to select multiple sources
of modeling data rather than a single modeling simulation if such
information is considered equally credible when making policy decisions
related to the development of good neighbor SIPs.
With respect to international emissions, MOG cited to an attachment
to EPA's 2018 memorandum and asserts that EPA's and Alpine's
contribution modeling tracks and reports the relative impact
contributions of anthropogenic emissions located within the 36 km
modeling domain. Considering this information, MOG concluded that
states seeking to avoid overcontrol may wish to consider removing that
portion of the projected design value that is explicitly attributed to
international anthropogenic contribution, which may be enough to
demonstrate attainment with the 2008 or 2015 8-hour ozone NAAQS at
multiple monitors in the U.S.
With respect to potential use of alternative contribution
thresholds, MOG pointed to states raising concerns that the 1 percent
threshold is more stringent than the 2016 EPA Significant Impact level
(SIL) guidance of 1 ppb, which is designed as an individual source or
group of sources' contribution limit (in the context of prevention of
significant deterioration (PSD) permitting).\45\ MOG suggested that
states could submit SIP revisions citing the SIL of 1 ppb as an
acceptable total state anthropogenic contribution threshold under Step
2 of the 4-step process, and request relief from the 1 percent
threshold in lieu of using an alternate value.
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\45\ MOG cited to the Georgia Environmental Protection
Division's comment on EPA's March 2018 Memorandum to support this
claim. See Section 9.0--Selected SIP Revision Approaches in Appendix
C--MOG's TSD of Kentucky's January 11, 2019 transport SIP
submission, citing Boylan, J. W. (May 4, 2018). Georgia EPD Comments
on EPA's March 27, 2018 Interstate Transport Memo [Memorandum].
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MOG presented an alternative approach to how upwind-state emission
reduction obligations could be allocated. Specifically, MOG proposed
that upwind reductions could be allocated in proportion to the size of
their contribution to downwind nonattainment. To illustrate this
approach, MOG determined a proportional reduction requirement
associated with the relative contribution from each upwind state to the
Harford County, Maryland monitor. Under this analysis, MOG's approach
indicated that Kentucky would be responsible for a 0.02 ppb reduction
at the monitor and ``would then need to craft a [good neighbor SIP]
revision to generate reductions associated with this proportional
amount.''
With respect to ``interference with maintenance'' obligations, MOG
suggested that an upwind state could choose to indicate that no
additional controls would be needed to address a maintenance monitor if
the upwind state can show that either the monitor is likely to remain
in attainment for a period of 10 years or that the upwind state's
emissions will not increase for 10 years after the attainment date.
III. EPA's Evaluation of Kentucky's 2015 8-Hour Ozone Interstate
Transport SIP Submission
EPA is proposing to find that Kentucky's January 11, 2019, SIP
submission does not meet the Commonwealth's obligations with respect to
prohibiting emissions that contribute significantly to nonattainment or
interfere with maintenance of the 2015 8-hour ozone NAAQS in any other
state based on EPA's evaluation of the SIP submission using the 4-step
interstate transport framework, and therefore EPA is proposing to
disapprove Kentucky's SIP submission.
A. Results of EPA's Step 1 and Step 2 Modeling and Findings for
Kentucky
As described in section I, EPA performed updated air quality
modeling to project design values and contributions for 2023. These
data were examined to determine if Kentucky contributes at or above the
threshold of 1 percent of the 2015 8-hour ozone NAAQS (0.70 ppb) to any
downwind nonattainment or maintenance receptor. As shown in Table 1,
the data \46\ indicate that in 2023, emissions from Kentucky contribute
greater than 1 percent of the standard to nonattainment or maintenance-
only receptors in Bucks County, Pennsylvania (ID: 420170012), New Haven
County, Connecticut (ID: 90099002), and Fairfield County, Connecticut
(ID: 90019003 and 90013007).\47\
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\46\ The ozone design values and contributions at individual
monitoring sites nationwide are provided in the file
``2016v2_DVs_state_contributions.xlsx'' which is included in Docket
No. EPA-HQ-OAR-2021-0663.
\47\ These modeling results are consistent with the results of a
prior round of 2023 modeling using the 2016v1 emissions platform
which became available to the public in the fall of 2020 in the
Revised CSAPR Update, as noted in section I. That modeling showed
that Kentucky had a maximum contribution greater than 0.70 ppb to at
least one nonattainment or maintenance-only receptor in 2023. These
modeling results are included in the file ``Ozone Design Values And
Contributions Revised CSAPR Update.xlsx'' in Docket No. EPA-HQ-OAR-
2021-0663.
[[Page 9508]]
Table 1--Kentucky Linkage Results Based on EPA Updated 2023 Modeling
--------------------------------------------------------------------------------------------------------------------------------------------------------
2023 average 2023 maximum Kentucky
Receptor ID Location County Nonattainment/ design value design value contribution
maintenance (ppb) (ppb) (ppb)
--------------------------------------------------------------------------------------------------------------------------------------------------------
420170012.......................... Pennsylvania......... Bucks................ Maintenance.......... 70.7 72.2 0.88
90099002........................... Connecticut.......... New Haven............ Nonattainment........ 71.8 73.9 0.83
90019003........................... Connecticut.......... Fairfield............ Nonattainment........ 76.1 76.4 0.82
90013007........................... Connecticut.......... Fairfield............ Nonattainment........ 74.2 75.1 0.77
--------------------------------------------------------------------------------------------------------------------------------------------------------
B. Evaluation of Information Provided by Kentucky Regarding Step 1
At Step 1 of the 4-step interstate transport framework, Kentucky
relied on EPA modeling released in the March 2018 memorandum to
identify nonattainment and maintenance receptors in 2023 and also
included results from modeling performed by Alpine. As described
previously in this notice, EPA has recently updated its 2023 modeling
using the most current and technically appropriate information. EPA
proposes to rely on EPA's most recent modeling to identify
nonattainment and maintenance receptors in 2023. However, even using
EPA modeling available to Kentucky at the time of its SIP submittal,
three nonattainment receptors and one maintenance-only receptor were
projected in 2023 to which Kentucky was linked above 1 percent of the
NAAQS. In addition, the Alpine modeling that Kentucky appended to its
submittal also indicated that Kentucky was linked to several receptors
in 2023.\48\ Kentucky appended comments from MOG arguing that states
should be allowed to select multiple sources of modeling data rather
than a single modeling simulation if such information is considered
equally credible when making policy decisions related to the
development of good neighbor SIPs. Whether EPA's most recent 2023
modeling is relied on, or whether it is considered in conjunction with
its older 2023 modeling and/or the Alpine modeling, the results
consistently identify several nonattainment or maintenance receptors to
which Kentucky is linked above 1 percent of the 2015 8-hour ozone
NAAQS.
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\48\ The Alpine modeling results identified the Harford,
Maryland receptor as a nonattainment receptor, with Kentucky
emissions contributing 2.07 ppb. In addition, the Alpine modeling
results identified Kentucky linkages above 1 percent to the
following maintenance-only receptors: Gloucester, New Jersey (ID:
340150002), with a Kentucky contribution of 1.69 ppb; Richmond, New
York (ID: 360850067), with a Kentucky contribution of 0.93; and
Philadelphia, Pennsylvania (ID: 421010024), with a Kentucky
contribution of 1.53.
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As discussed in section II.E, Kentucky attached documents from MOG
that discussed international transport of emissions and their
contribution to U.S. ozone monitors, and argued that states could
remove that portion of the projected design value explicitly attributed
to international anthropogenic contribution. MOG asserted that
excluding the international anthropogenic contributions could result in
attainment with the 2008 or 2015 8-hour ozone NAAQS at ozone monitors
in the United States, thus potentially eliminating 2023 receptors.
Kentucky did not explicitly discuss in its SIP submittal MOG's
arguments regarding contributions from international emissions and
therefore it is unclear if the Commonwealth intended to rely on this
argument to support their conclusion, however, EPA is providing its
analysis related to these arguments.
EPA disagrees that excluding international contribution (whether
from North American international anthropogenic, boundary conditions,
or other international sources) from the projected design value of
receptors is acceptable under the CAA.\49\ The good neighbor provision
requires states and EPA to address interstate transport of air
pollution that contributes to downwind states' ability to attain and
maintain NAAQS. Whether emissions from other states or other countries
also contribute to the same downwind air quality issue is irrelevant in
assessing whether a downwind state has an air quality problem, or
whether an upwind state is significantly contributing to that problem.
States are not obligated under CAA section 110(a)(2)(D)(i)(I) to reduce
emissions sufficient on their own to resolve downwind receptors'
nonattainment or maintenance problems. Rather, states are obligated to
eliminate their own ``significant contribution'' or ``interference''
with the ability of other states to attain or maintain the NAAQS.
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\49\ To the extent that MOG cited Attachment A to EPA's March
2018 memorandum as suggesting support for this approach, this is
incorrect. As discussed in section I.D, the attachment summarized
ideas from outside stakeholders, and EPA did not endorse such
approaches as technically or legally appropriate. Further, nothing
in Attachment A suggested that international contribution could
simply be subtracted from a downwind receptor's projected design
value.
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Indeed, the D.C. Circuit in Wisconsin specifically rejected
petitioner arguments suggesting that upwind states should be excused
from good neighbor obligations on the basis that some other source of
emissions (whether international or another upwind state) could be
considered the ``but-for'' cause of downwind air quality problem. See
938 F.3d at 323-324. The court viewed petitioners' arguments as
essentially an argument ``that an upwind State `contributes
significantly' to downwind nonattainment only when its emissions are
the sole cause of downwind nonattainment.'' See 938 F.3d at 324. The
court explained that ``an upwind State can `contribute' to downwind
nonattainment even if its emissions are not the but-for cause.'' Id. at
324-325. See also Catawba County v. EPA, 571 F.3d 20, 39 (D.C. Cir.
2009) (rejecting the argument ``that `significantly contribute'
unambiguously means `strictly cause' '' because there is ``no reason
why the statute precludes EPA from determining that [an] addition of
[pollutant] into the atmosphere is significant even though a nearby
county's nonattainment problem would still persist in its absence'');
Miss. Comm'n on Envtl. Quality v. EPA, 790 F.3d 138, 163 n.12 (D.C.
Cir. 2015) (observing that the argument that ``there likely would have
been no violation at all . . . if it were not for the emissions
resulting from [another source]'' is ``merely a rephrasing of the but-
for causation rule that we rejected in Catawba County.''). Therefore, a
state is not excused from eliminating its significant contribution on
the basis that international emissions also contribute some amount of
pollution to the same receptors to which the state is linked.
C. Evaluation of Information Provided by Kentucky Regarding Step 2
At Step 2 of the 4-step interstate transport framework, Kentucky
relied on EPA modeling released in the March 2018 memorandum to
identify upwind state linkages to nonattainment and maintenance
receptors in 2023 and included results from modeling run by
[[Page 9509]]
Alpine. Both EPA's modeling released in the March 2018 memorandum as
well as Alpine's modeling indicate that Kentucky is linked to downwind
monitors.\50\ As Kentucky attached Alpine's modeling without discussing
it in the narrative of the submittal, it is unclear whether Kentucky
intended to rely on Alpine's modeling in its submittal.
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\50\ Although the various modeling runs (EPA's March 2018
modeling, Alpine's modeling and EPA's updated modeling) indicate
that Kentucky is linked to different receptors and with differing
amounts of contribution, all three sets of modeling are consistent
in that each indicates linkages between Kentucky and downwind
receptors.
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As described in section I.C of this notice, EPA has recently
updated modeling to identify upwind state contributions to
nonattainment and/or maintenance receptors in 2023. In this notice, EPA
proposes to rely on the Agency's most recently available modeling to
identify upwind contributions and ``linkages'' to downwind air quality
problems in 2023 using a threshold of 1 percent of the NAAQS. See
section I.D for a general explanation of the use of 1 percent of the
NAAQS.
As shown in Table 1, updated EPA modeling identifies Kentucky's
maximum contribution to a downwind nonattainment or maintenance
receptor is greater than 1 percent of the standard (i.e., 0.70 ppb).
Kentucky, however, argued in its SIP submittal for the use of an
alternative 1 ppb contribution threshold at Step 2 to attempt to
demonstrate that it was no longer ``linked'' to projected downwind
nonattainment receptors. Specifically, Kentucky cited EPA's August 2018
memorandum as supporting the use of a 1 ppb alternative contribution
threshold at Step 2 to assert that the Commonwealth was no longer
``linked'' to projected downwind nonattainment receptors, while
conceding that even under this alternative threshold, it was linked
above 1 ppb to the projected Harford, Maryland maintenance-only
receptor. EPA's most recent modeling of 2023 no longer identifies the
Harford, Maryland monitoring site as either a maintenance or
nonattainment receptor. Nonetheless, Kentucky is linked above 1 percent
of the NAAQS but less than 1 ppb to the four receptors in EPA's most
recent modeling. Therefore, whether Kentucky's use of an alternative 1
ppb contribution threshold is approvable is potentially a dispositive
question in EPA's evaluation.
EPA proposes to find that Kentucky's reliance on an alternative
contribution threshold of 1 ppb at Step 2 is not approvable. EPA
acknowledges that the August 2018 memorandum generally recognized that
a 1 ppb threshold may be appropriate for states to use, but also made
clear that this guidance would be applied under the facts and
circumstances of each particular SIP submittal.\51\ However, Kentucky
did not provide a technical analysis to sufficiently justify use of an
alternative 1 ppb threshold at the linked, downwind monitors.
Kentucky's SIP submission simply stated that the Commonwealth agrees
with EPA's rationale set out in the August 2018 memorandum that the
amount of upwind collective contribution captured with the 1 percent
and 1 ppb thresholds was generally comparable. But the guidance
anticipated that states would evaluate whether the alternative
threshold was appropriate under their specific facts and circumstances,
not that the use of the alternative threshold would be automatically
approvable.\52\ With respect to the assertion that 1 ppb was generally
comparable to 1 percent, Kentucky did not provide discussion or
analysis containing information specific to Kentucky or a receptor
analysis for the affected monitors, as anticipated in the 2018
memorandum, to evaluate whether the alternative threshold was
appropriate to apply with respect to the monitors to which Kentucky was
linked. Such state-specific information is necessary to thoroughly
evaluate the state-specific circumstances that could support approval.
Given the absence of technical analysis to support the use of a 1 ppb
threshold under the facts and circumstances relevant to Kentucky and
its linked receptors, EPA proposes that the use of 1 ppb as a
contribution threshold is not approvable.\53\ (As discussed in section
III.C.1 below, EPA no longer intends to dedicate resources to
supplement state submittals with insufficient analysis in this regard,
and also has identified other policy and programmatic concerns with
attempting to recognize alternative thresholds at Step 2 or otherwise
deviating from its historical, consistent practice since CSAPR of
applying a threshold of 1 percent of the NAAQS at Step 2.)
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\51\ See August 2018 memorandum at 1.
\52\ As an example of the type of analysis that EPA anticipated
states might conduct under the guidance, in one instance, EPA itself
attempted to conduct a state- and receptor-specific analysis that
could support approval of the use of a 1 ppb threshold. See Air Plan
Approval; Iowa; Infrastructure State Implementation Plan
Requirements for the 2015 Ozone National Ambient Air Quality
Standard, 85 FR 12232 (March 2, 2020). The Agency received adverse
comment on this proposed approval and has not taken final action
with respect to this proposal.
\53\ Kentucky applied the 1 ppb contribution threshold to the
Connecticut, Wisconsin, and Maryland receptors, as the Commonwealth
found that Kentucky was linked to these receptors based on the
modeling released with the March 2018 memorandum. Under EPA's
updated modeling, Kentucky is no longer linked to the Wisconsin and
Maryland receptors and is linked to receptors in Pennsylvania and
New Haven, Connecticut. See Table 1. However, as Kentucky did not
provide any state-specific information, the rationale is also
applicable to the Pennsylvania and New Haven, Connecticut linkages.
---------------------------------------------------------------------------
The MOG materials appended to Kentucky's submission argued that a
2016 EPA SIL guidance could be cited as acceptable to support a 1 ppb
contribution threshold. As an initial matter, Kentucky appears not to
have relied on this rationale. In EPA's comments on Kentucky's draft
SIP submittal, EPA stated, ``EPA has not made a determination that the
SIL, developed for source-specific (PSD) purposes, could be considered
an appropriate threshold to use when assessing contribution from an
entire state.'' \54\ Kentucky stated in response that it ``concurs with
the comment'' and had adjusted its SIP submittal accordingly.\55\
Further, even if the State had attempted to rely on the SIL as support
for a 1 ppb threshold, the basis supplied by MOG is inadequate. The SIL
is an analytical metric used in the context of PSD permitting, a part
of the CAA's ``prevention of significant deterioration'' program, which
generally is applicable in areas that designated attainment \56\ or
unclassifiable for the NAAQS. Good neighbor analysis for the ozone
NAAQS, by contrast, addresses the degree of significant contribution to
nonattainment and interference with maintenance of the NAAQS resulting
at downwind receptors from the collective contribution of many upwind
sources. Further, it is not correct to conflate the
[[Page 9510]]
use of the term ``significance'' as used in the SIL guidance, with the
term ``contribution,'' which is the appliable statutory term that EPA
applies at Step 2 of the 4-step interstate transport framework.
(``Significance'' within the 4-step framework is evaluated at Step 3
through a multifactor analysis, for those states that are determined to
``contribute'' to downwind receptors at Steps 1 and 2. See section
I.D.4.) Given the fundamentally different statutory objectives and
context, EPA disagrees with MOG's contention that the SIL guidance is
applicable in the good neighbor context.
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\54\ See Kentucky's January 11, 2019, submission, Appendix D,
Summary of Comments and Responses, at 6-7.
\55\ Id. at 7. EPA directed Kentucky instead to the August 2018
memorandum if it wished to rely on a 1 ppb threshold; however, EPA's
comments noted that this memorandum was only a ``part'' of the
rationale the Commonwealth should develop. Id. at 6.
\56\ Pursuant to section 107(d) of the CAA, EPA must designate
areas as either ``nonattainment,'' ``attainment,'' or
``unclassifiable.'' Historically for ozone, the EPA has designated
most areas that do not meet the definition of nonattainment as
``unclassifiable/attainment.'' This category includes areas that
have air quality monitoring data meeting the NAAQS and areas that do
not have monitors but for which the EPA has no evidence that the
areas may be violating the NAAQS or contributing to a nearby
violation. In the designations for the 2015 ozone NAAQS, the EPA
reversed the order of the label to be ``attainment/unclassifiable''
to better convey the definition of the designation category and so
that the category is more easily distinguished from the separate
unclassifiable category. An ``attainment'' designation is reserved
for a previous nonattainment area that has been redesignated to
attainment as a result of the EPA's approval of a CAA section 175A
maintenance plan submitted by the state air agency.
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1. EPA's Experience With Alternative Step 2 Thresholds
EPA here shares further evaluation of its experience since the
issuance of the August 2018 memorandum regarding use of alternative
thresholds at Step 2. This experience leads the Agency to now believe
it may not be appropriate to continue to attempt to recognize
alternative contribution thresholds at Step 2. The August 2018
memorandum stated that ``it may be reasonable and appropriate'' for
states to rely on an alternative threshold of 1 ppb threshold at Step
2.\57\ (The memorandum also indicated that any higher alternative
threshold, such as 2 ppb, would likely not be appropriate.) However,
EPA also provided that ``air agencies should consider whether the
recommendations in this guidance are appropriate for each situation.''
Following receipt and review of 49 good neighbor SIP submittals for the
2015 8-hour ozone NAAQS, EPA's experience has been that nearly every
state that attempted to rely on a 1 ppb threshold did not provide
sufficient information and analysis to support a determination that an
alternative threshold was reasonable or appropriate for that state.
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\57\ See August 2018 memorandum at 4.
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For instance, in nearly all submittals, the states did not provide
EPA with analysis specific to their state or the receptors to which its
emissions are potentially linked. In one case, the proposed approval of
Iowa's SIP submittal, EPA expended its own resources to attempt to
supplement the information submitted by the state, in order to more
thoroughly evaluate the state-specific circumstances that could support
approval.\58\ It was at EPA's sole discretion to perform this analysis
in support of the state's submittal, and the Agency is not obligated to
conduct supplemental analysis to fill the gaps whenever it believes a
state's analysis is insufficient. The Agency no longer intends to
undertake supplemental analysis of SIP submittals with respect to
alternative thresholds at Step 2 for purposes of the 2015 8-hour ozone
NAAQS.
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\58\ Air Plan Approval; Iowa; Infrastructure State
Implementation Plan Requirements for the 2015 Ozone National Ambient
Air Quality Standard, 85 FR 12232 (March 2, 2020). The Agency
received adverse comment on this proposed approval and has not taken
final action with respect to this proposal.
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Furthermore, EPA's experience since 2018 is that allowing for
alternative Step 2 thresholds may be impractical or otherwise
inadvisable for a number of additional policy reasons. For a regional
air pollutant such as ozone, consistency in requirements and
expectations across all states is essential. Based on its review of
submittals to-date and after further consideration of the policy
implications of attempting to recognize an alternative Step 2 threshold
for certain states, the Agency now believes the attempted use of
different thresholds at Step 2 with respect to the 2015 8-hour ozone
NAAQS raises substantial policy consistency and practical
implementation concerns.\59\ The availability of different thresholds
at Step 2 has the potential to result in inconsistent application of
good neighbor obligations based solely on the strength of a state's
implementation plan submittal at Step 2 of the 4-step interstate
transport framework. From the perspective of ensuring effective
regional implementation of good neighbor obligations, the more
important analysis is the evaluation of the emissions reductions
needed, if any, to address a state's significant contribution after
consideration of a multifactor analysis at Step 3, including a detailed
evaluation that considers air quality factors and cost. Where
alternative thresholds for purposes of Step 2 may be ``similar'' in
terms of capturing the relative amount of upwind contribution (as
described in the August 2018 memorandum), nonetheless, use of an
alternative threshold would allow certain states to avoid further
evaluation of potential emission controls while other states must
proceed to a Step 3 analysis. This can create significant equity and
consistency problems among states.
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\59\ EPA notes that Congress has placed on EPA a general
obligation to ensure the requirements of the CAA are implemented
consistently across states and regions. See CAA section 301(a)(2).
Where the management and regulation of interstate pollution levels
spanning many states is at stake, consistency in application of CAA
requirements is paramount.
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Further, it is not clear that national ozone transport policy is
best served by allowing for less stringent thresholds at Step 2. EPA
recognized in the August 2018 memorandum that there was some similarity
in the amount of total upwind contribution captured (on a nationwide
basis) between 1 percent and 1 ppb. However, EPA notes that while this
may be true in some sense, that is hardly a compelling basis to move to
a 1 ppb threshold. Indeed, the 1 ppb threshold has the disadvantage of
losing a certain amount of total upwind contribution for further
evaluation at Step 3 (e.g., roughly 7 percent of total upwind state
contribution was lost according to the modeling underlying the August
2018 memorandum; \60\ in EPA's updated modeling, the amount lost is 5
percent). Considering the core statutory objective of ensuring
elimination of all significant contribution to nonattainment or
interference of the NAAQS in other states and the broad, regional
nature of the collective contribution problem with respect to ozone,
there does not appear to be a compelling policy imperative in allowing
some states to use a 1 ppb threshold while others rely on a 1 percent
of the NAAQS threshold.
---------------------------------------------------------------------------
\60\ See August 2018 memorandum at 4.
---------------------------------------------------------------------------
Consistency with past interstate transport actions such as CSAPR,
and the CSAPR Update and Revised CSAPR Update rulemakings (which used a
Step 2 threshold of 1 percent of the NAAQS for two less stringent ozone
NAAQS), is also important. Continuing to use a 1 percent of NAAQS
approach ensures that as the NAAQS are revised and made more stringent,
an appropriate increase in stringency at Step 2 occurs, so as to ensure
an appropriately larger amount of total upwind-state contribution is
captured for purposes of fully addressing interstate transport. See 76
FR 48208, 48237-38 (August 8, 2011).
Therefore, notwithstanding the August 2018 memorandum's recognition
of the potential viability of alternative Step 2 thresholds, and in
particular, a potentially applicable 1 ppb threshold, EPA's experience
since the issuance of that memorandum has revealed substantial
programmatic and policy difficulties in attempting to implement this
approach. Nonetheless, EPA is not at this time rescinding the August
2018 memorandum. The basis for disapproval of Kentucky's SIP submission
with respect to the Step 2 analysis is, in the Agency's view, warranted
even under the terms of the August 2018 memorandum. EPA invites comment
on this broader discussion of issues associated with alternative
thresholds at Step 2. Depending on comment and further evaluation of
this issue, EPA may determine to rescind the August 2018 memorandum in
the future.
[[Page 9511]]
In summary, EPA's updated modeling indicates that emissions from
Kentucky sources are linked to downwind receptors identified in Table
1, and application of 1 ppb alternative threshold is not supported by
Kentucky's SIP submission. Thus, EPA preliminarily finds that Kentucky
is linked to downwind nonattainment and maintenance receptors, and
proceeds to Step 3 of the 4-step framework.
D. Evaluation of Information Provided by Kentucky Regarding Step 3
At Step 3 of the 4-step interstate transport framework, a state's
emissions are further evaluated, in light of multiple factors,
including air quality and cost considerations, to determine what, if
any, emissions significantly contribute to nonattainment or interfere
with maintenance and, thus, must be eliminated under CAA section
110(a)(2)(D)(i)(I).
To effectively evaluate which emissions in the state should be
deemed ``significant'' and therefore prohibited, states generally
should prepare an accounting of sources and other emissions activity
for relevant pollutants and assess potential, additional emissions
reduction opportunities and resulting downwind air quality
improvements. EPA has consistently applied this general approach (i.e.,
Step 3 of the 4-step interstate transport framewor46k) when identifying
emissions contributions that the Agency has determined to be
``significant'' (or interfere with maintenance) in each of its prior
Federal, regional ozone transport rulemakings, and this interpretation
of the statute has been upheld by the Supreme Court. See EME Homer
City, 572 U.S. 489, 518-520 (2014). While EPA has not directed states
that they must conduct a Step 3 analysis in precisely the manner EPA
has done in its prior regional transport rulemakings, state
implementation plans addressing the obligations in CAA section
110(a)(2)(D)(i)(I) must prohibit ``any source or other type of
emissions activity within the State'' from emitting air pollutants
which will contribute significantly to downwind air quality problems.
Thus, states must complete something similar to EPA's analysis (or an
alternative approach to defining ``significance'' that comports with
the statute's objectives) to determine whether and to what degree
emissions from a state should be ``prohibited'' to eliminate emissions
that will ``contribute significantly to nonattainment in, or interfere
with maintenance of'' the NAAQS in any other state. Kentucky did not
conduct such an analysis in its SIP submission.
Kentucky did not include a comprehensive accounting of facilities
in the Commonwealth and did not include a sufficient analysis of
potential NOX emissions control technologies, their
associated costs, estimated emissions reductions, and downwind air
quality improvements for the purpose of identifying what additional
emission controls may be necessary to eliminate their significant
contribution. Rather, Kentucky's SIP included air quality analysis
related to downwind receptors and relied on existing NOX
emission measures in the Commonwealth without any rationale to show how
or why existing measures would eliminate the Kentucky's downwind
contribution. Further, the Commonwealth provided information related to
programs that it asserted were responsible for a 10-year decline in
ozone season NOX emissions in Kentucky, such as regulations
and Federal programs (including the CSAPR Update), EGU shutdowns,
retirements, and fuel switches. However, Kentucky did not quantify the
NOx emission reduction potential of on-the-books regulations or Federal
programs or on-the-way measures for 2023, nor does the submission
consider cost-effectiveness of potential emissions controls, the total
emissions reductions that may be achieved by requiring these controls,
or an evaluation of the air quality impacts such emissions reductions
would have on the downwind receptors to which Kentucky is linked.
Identifying a range of on-the-books emissions control measures that
have been or may be enacted at the state or local level, without
analysis of the impact of those measures on the downwind receptors, is
not a sufficient analysis.
Furthermore, the emissions-reducing effects of on-the-books
emissions control requirements are already reflected in the air quality
results of EPA's modeling under Steps 1 and 2 of the 4-step framework.
Kentucky, and MOG in the materials it submitted to Kentucky, maintain
that there were additional emission reductions that have occurred that
were not accounted for in EPA's 2023 modeling as presented in the March
2018 memorandum. Kentucky cites the 2019 retirement of units 1 and 2 at
the E.W. Brown coal-fired power plant (see Appendix D, Response to
Comments, at 5), and MOG claims a variety of unidentified changes not
accounted for in EPA's emissions inventory at the time of the modeling
in the March 2018 memorandum, as well as certain downwind state
measures apparently under consideration but not adopted, and certain
changes in the Wisconsin EGU fleet (see Alpine TSD, Appendix B, at
pages B-5, B-6). In general, any changes in the emissions inventory and
on-the-books controls relevant to emissions in 2023 have now been
incorporated into EPA's most recent modeling of 2023. This includes
changes in Kentucky EGU emissions.
As previously discussed, EPA's updated modeling indicates sources
in Kentucky are linked to downwind air quality problems for the 2015 8-
hour ozone standard. However, Kentucky's SIP submittal did not include
a sufficient accounting of emissions sources or activity in the
Commonwealth, along with an analysis of potential NOX
emissions control technologies, associated costs, estimated emissions
reductions, and downwind air quality improvements to eliminate the
Kentucky's downwind contribution.
EPA therefore propose to find that Kentucky was required to analyze
emissions from the sources and other emissions activity from within the
Commonwealth to determine whether its contributions were significant,
and EPA proposes to disapprove its submission because Kentucky failed
to do so.
The subsections below contain additional detail with respect to
arguments made by the Commonwealth in its SIP submission.\61\
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\61\ These subsections provide brief summaries of the issues as
presented in Kentucky's SIP as context; please see section II of
this notice for additional detail on the contents of Kentucky's SIP.
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1. Evaluation of Kentucky's Reliance on Existing and Future
NOX Emission Reductions
The Commonwealth's SIP submission does not contain a Step 3
analysis regarding future emissions reduction opportunities beyond
pointing to NOX emission reductions from expected
retirements, fuel switching, and shutdowns. While the Commonwealth
claimed there would be an estimated 471 tons of NOX
emissions from potential shutdown of units at the E.W. Brown Generating
Station facility in Harrodsburg, Kentucky, the Commonwealth did not
clarify how these planned reductions would resolve the Commonwealth's
downwind contribution to the Harford County, Maryland maintenance-only
receptor by 2023. (Nor did the Commonwealth evaluate whether emissions
may increase at other sources whose generation would replace that lost
at E. W. Brown.) Further, the E.W. Brown facility retired coal-fired
units 1 and 2
[[Page 9512]]
in February 2019,\62\ the units' retirement is included in the recently
updated modeling for Steps 1 and 2, and yet emissions from Kentucky
sources remain linked to one or more downwind receptors.
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\62\ See Retired Unit exemption forms for E.W. Brown Generating
station in Docket No.: EPA-R04-OAR-2021-0841.
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While the Commonwealth generally asserted that on-the-books or on-
the-way regulations and programs may provide future emissions
reductions, Kentucky did not quantify these reductions in a meaningful
way or demonstrate that the downwind improvements from these
regulations and programs would be sufficient to eliminate the
Commonwealth's significant contribution or interference with
maintenance. In addition, the SIP submission did not evaluate or even
attempt to identify additional control measures for EGUs or non-EGUs,
nor did it include a determination of emission reduction potential for
these potential additional controls or consider their cost-
effectiveness or downwind air quality effects. This is not a sufficient
Step 3 analysis.
2. Evaluation of Kentucky's Reliance on Prior Transport FIPs
The 10-year emission reductions discussed by Kentucky relies in
part on the implementation of CAIR, CSAPR, and the CSAPR Update.
Kentucky's SIP relied on its EGUs being subject to the CSAPR Update
(which reflected a stringency at the nominal marginal cost threshold of
$1,400/ton (in 2011 dollars) for the 2008 8-hour ozone NAAQS) to argue
that it has already implemented all cost-effective emissions reductions
to support its conclusion that additional NOX emission
reductions are not necessary from sources in Kentucky. Kentucky did not
conduct a comprehensive Step 3 analysis or provide any justification
for reliance on the CSAPR Update beyond identifying the NOX
emission reductions that the Commonwealth believes are the source of
the 10-year decline in NOX emissions at EGUs in the
Commonwealth and noting that the actual emissions from EGUs in the
Commonwealth are well below the CSAPR Update NOX ozone
season trading budget.
EPA disagrees with the Commonwealth. Reliance on the CSAPR Update
(or the subsequent Revised CSAPR Update, which fully resolved
Kentucky's good neighbor obligations for the 2008 ozone NAAQS, 86 FR
23056-57), is insufficient because those policies addressed section
110(a)(2)(D)(i)(I) only for the 2008 ozone NAAQS. Additionally,
reliance on an alleged cost-threshold stringency from the CSAPR Update
is insufficient without additional Step 3 analysis and justification.
First, the CSAPR Update did not regulate non-EGUs, and thus this
analysis would have been incomplete, even with respect to obligations
under the 2008 ozone NAAQS. See Wisconsin, 938 F.3d at 318-20. Second,
relying on the CSAPR Update's (or any other CAA program's)
determination of cost-effectiveness without further Step 3 analysis is
not approvable. Cost-effectiveness must be assessed in the context of
the specific CAA program; assessing cost-effectiveness in the context
of ozone transport should reflect a more comprehensive evaluation of
the nature of the interstate transport problem under the relevant
NAAQS, the total emissions reductions available at alternative cost
thresholds, and the air quality impacts of the reductions at downwind
receptors. While EPA has not established a benchmark cost-effectiveness
value for 2015 8-hour ozone NAAQS interstate transport obligations,
because the 2015 8-hour ozone NAAQS is a more stringent and more
protective air quality standard, it is reasonable to expect control
measures or strategies to address interstate transport under this NAAQS
to reflect higher marginal control costs. As such, the marginal cost
threshold of $1,400/ton for the CSAPR Update (which addresses the 2008
ozone 8-hour NAAQS and is in 2011 dollars) is not an appropriate cost
threshold and cannot be approved as a benchmark to use for interstate
transport SIP submissions for the 2015 8-hour ozone NAAQS.
In addition, the updated EPA modeling captures all existing CSAPR
trading programs in the baseline, and that modeling confirms that these
control programs were not sufficient to eliminate the Kentucky's
linkage at Steps 1 and 2 under the 2015 8-hour ozone NAAQS. Kentucky
was therefore obligated at Step 3 to assess additional control measures
using a multifactor analysis.
Finally, relying on a FIP at Step 3 is per se not approvable if the
state has not adopted that program into its SIP and instead continues
to rely on the FIP. States may not rely on non-SIP measures to meet SIP
requirements. See CAA section 110(a)(2)(D) (``Each such [SIP] shall . .
. contain adequate provisions. . . .''). See also CAA section
110(a)(2)(A); Committee for a Better Arvin v. U.S. E.P.A., 786 F.3d
1169, 1175-76 (9th Cir. 2015) (holding that measures relied on by state
to meet CAA requirements must be included in the SIP). Kentucky has not
adopted the Group 3 NOX Ozone Season Trading Program
promulgated in the Revised CSAPR Update into its SIP.
3. Evaluation of Kentucky's Analysis of Air Quality and Emission
Reductions Near the Linked Monitors
Kentucky's SIP also evaluated air quality in the vicinity of the
Fairfield County, Connecticut (IDs: 090013007 and 090019003) and
Harford County, Maryland (ID: 240251001) monitors for which the
Commonwealth is linked based on EPA's modeling in the March 2018
memorandum. Kentucky's submission asserts that the primary cause of
nonattainment problems at the Connecticut and Maryland monitors are due
to local emissions of ozone precursors (particularly NOX)
and meteorological conditions.
Kentucky's SIP submittal argues against control requirements on
Kentucky sources to address the two nonattainment receptors in
Fairfield, Connecticut (IDs: 090013007, 090019003) and the maintenance-
only monitor in Harford County, Maryland monitor, claiming that
additional emission reductions from Kentucky EGUs (the only Kentucky
source category discussed in the submittal) are not necessary. Kentucky
concludes that local emissions reductions should be applied before
requiring Kentucky to control its sources, and that the implementation
of local programs to reduce emissions should be sufficient for monitors
in the area to attain the 2015 8-hour ozone NAAQS.\63\
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\63\ The Commonwealth's submission cites to MOG's statements
regarding controls on local sources ``When an area is measuring
nonattainment of a NAAQS, as is the case with the areas linked to
Kentucky, the CAA requires that the effects and benefits of local
controls on all source sectors be considered first, prior to
pursuing controls of sources in upwind states.''
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With respect to the information Kentucky provided that is related
to local emissions and the impact on air quality at the Connecticut and
Maryland receptors, this information is insufficient to approve
Kentucky's SIP submission. Regardless of whether local emissions are
the largest contributor to a specific nonattainment or maintenance
receptor, the good neighbor provision requires that upwind states
prohibit emissions that contribute significantly to nonattainment or
interfere with maintenance of the NAAQS in downwind states. EPA
evaluates a state's obligations to eliminate interstate transport
emissions under the interstate transport provision according to EPA's
4-step process, and EPA's updating modeling at Steps 1 and
[[Page 9513]]
2 has identified a linkage between emission from Kentucky sources and
downwind nonattainment and maintenance receptors.
Further, EPA disagrees with Kentucky's claims that local emissions
reductions from the jurisdiction where the downwind receptor is located
must first be implemented and accounted for before imposing obligations
on upwind states under the interstate transport provision. There is
nothing in the CAA that supports that position, and it does not provide
grounds on which to approve Kentucky SIP submission. The D.C. Circuit
has held on five different occasions that the timing framework for
addressing interstate transport obligations must be consistent with the
downwind areas' attainment schedule. In particular, for the ozone
NAAQS, the states and EPA are to address interstate transport
obligations ``as expeditiously as practicable'' and no later than the
attainment schedule set in accordance with CAA section 181(a). See
North Carolina, 531 F.3d at 911-13; Wisconsin, 938 F.3d at 313-20;
Maryland, 958 F.3d at 1204; New York v. EPA, 964 F.3d 1214, 1226 (D.C.
Cir. 2020); New York v. EPA, 781 Fed. App'x 4, 6-7 (D.C. Cir. 2019).
The court in Wisconsin explained its reasoning in part by noting that
downwind jurisdictions often may need to heavily rely on emissions
reductions from upwind states in order to achieve attainment of the
NAAQS, 938 F.3d at 316-17; such states would face increased regulatory
burdens including the risk of bumping up to a higher nonattainment
classification if attainment is not reached by the relevant deadline.
Maryland, 958 F.3d at 1204. The statutory framework of the CAA and
these cases establish clearly that states and EPA must address
interstate transport obligations in line with the attainment schedule
provided in the Act in order to timely assist downwind states in
attaining and maintain the NAAQS, and this schedule is ``central to the
regulatory scheme.'' Wisconsin, 938 F.3d at 316 (quoting Sierra Club v.
EPA, 294 F.3d 155, 161 (D.C. Cir. 2002)).
In addition, Kentucky's SIP does not provide a technical
justification to support its conclusion that local emissions reductions
at the receptors will achieve attainment without upwind reductions from
sources within Kentucky. Specifically, Kentucky does not provide any
information to support its claim that the implementation of local
programs alone will address the air quality problems at the Connecticut
and Maryland monitors. Even with the consideration of on-the-books
control measures to reduce mobile source emissions, EPA's modeling
projects that the total contribution from upwind states is a
substantial part of the ozone problem at the nonattainment and
maintenance receptors to which Kentucky is linked. To illustrate this,
at the four receptors to which Kentucky is linked in EPA's latest 2023
modeling, the total percent of U.S. anthropogenic emissions from upwind
states is 55 percent (Bucks Co., Pennsylvania), 90 percent (New Haven
Co., Connecticut), 90 percent (Fairfield Co.--Stratford, Connecticut),
and 94 percent (Fairfield Co.--Westport, Connecticut) of the total
design values at these receptors. Clearly, emissions reductions from
upwind states would have an impact on the design values at the
identified receptors.\64\
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\64\ In contrast to the receptors to which Kentucky is linked,
EPA has found that certain receptors are so heavily impacted by
local emissions that they should not be considered ``transport''
receptors for purposes of the ozone NAAQS. Typically, in such cases,
only one state is linked above 1 percent to that receptor and the
total upwind state contribution is on the order of 2 percent to 4
percent of the receptor's DV. See, e.g., 81 FR 15200 (March 22,
2016), 81 FR 31513 (May 19, 2016), and 81 FR 36179 (June 6, 2016)
(approving Arizona's transport SIP on basis that certain California
receptors should not be considered impacted by interstate ozone
transport).
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Additionally, the SIP submission does not assess whether the
Commonwealth's own emissions contributed to nonattainment or interfered
with maintenance at the linked receptors, or rather substantiate that
emissions from the Commonwealth's sources were not interacting with
these monitors. Consequently, the application of local emission
reduction measures does not absolve upwind states and sources from the
responsibility of addressing their significant contribution. Moreover,
Kentucky still has an obligation under the Act to address its downwind
contribution to ozone nonattainment or interference with maintenance
regardless of the emission reduction potential for local control
measures. Furthermore, given that EPA's updated modeling indicates that
Kentucky is linked to nonattainment and maintenance receptors at Step 2
including the same Fairfield County, Connecticut nonattainment
receptors as were linked in the modeling released with the March 2018
memorandum, EPA disagrees with Kentucky's claims regarding the
application of local emission reduction measures with respect to its
downwind linkages in the most recent modeling.
4. Evaluation of Kentucky's HYSPLIT Analysis
Kentucky's SIP submittal also included HYSPLIT model back
trajectory analysis, which Kentucky used to emphasize the local nature
of the ozone precursor emissions at the two Connecticut receptors,
mobile sources along the I-95 Corridor, and the proximity of large
point sources and ozone nonattainment areas in New York, New Jersey,
Pennsylvania, and Maryland. Similarly, Kentucky also evaluated HYSPLIT
back-trajectory for the Harford County, Maryland monitor and noted
similar localized emissions impacts with respect to the Maryland
monitor as discussed previously for the two Fairfield County,
Connecticut monitors.
However, the limited information provided by Kentucky is not
adequate to support approval of Kentucky's SIP on this basis and in the
absence of a more complete Step 3 evaluation. Kentucky's SIP submittal
did not address that the HYSPLIT back-trajectories indicate that ozone
precursor emissions sources in Kentucky are upwind of the linked
nonattainment receptors in Connecticut (regardless of the existence of
other upwind nonattainment areas that may also be contributing to those
receptors). Additionally, the HYSPLIT trajectory information provided
by Kentucky was developed by EPA to inform the 2015 8-hour ozone NAAQS
area designations and was not intended to evaluate long-distance
interstate transport.\65\
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\65\ See Area Designations for the 2015 Ozone National Ambient
Air Quality Standards memorandum from Janet G. McCabe to EPA
Regional Administrators, February 25, 2016 (2015 ozone Area
Designations memorandum).
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Attachment 3 of the 2015 8-hour ozone Area Designations memorandum
states that the line thickness displayed on trajectory plots ``does not
imply coverage other than to represent the centerline of an air
parcel's motion calculated to arrive at the starting location at the
starting time. Uncertainties are clearly present in these results and
these uncertainties change with trajectory time and distance traveled.
One should avoid concluding a region is not along a trajectory's path
if the center line of that trajectory missed the region by a relatively
small distance.'' \66\
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\66\ See id. It is important to understand that HYSPLIT back
trajectory analyses use archived meteorological modeling that
includes actual observed data (surface, upper air, airplane data,
etc.) and modeled meteorological fields to estimate the most likely
route of an air parcel transported to a receptor at a specified
time. The method essentially follows a parcel of air backward in
hourly steps for a specified length of time. HYSPLIT estimates the
central path in both the vertical and horizontal planes. The HYSPLIT
central path represents the centerline with the understanding that
there are areas on each side horizontally and vertically that also
contribute to the end point at the monitor. The horizontal and
vertical areas from the centerline grow wider the further back in
time the trajectory goes. Therefore, a HYSPLIT centerline does not
have to pass directly over emissions sources or emission source
areas but merely relatively near emission source areas.
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[[Page 9514]]
Further, the back trajectories used by Kentucky were limited to
evaluating transport of air parcels over a relatively short 24-hour
period, which limits their use for evaluating long-distance transport
of emissions from Kentucky to the Fairfield, Connecticut receptors and
the Harford, Maryland receptor. In contrast, EPA's analysis of
transported emissions as discussed in section III.A uses updated,
photochemical grid modeling designed to assess ozone transported to
downwind monitors across the entire region and over extended timeframes
that fully account for fate and transport of ozone-precursors over
longer distances.
Kentucky's SIP submission states that the Fairfield County ozone
monitors are located in the New York Metro Area, in close proximity to
the I-95 transportation artery. The Commonwealth's analysis asserts a
high VMT and number of commuters in the area indicating the presence of
mobile emissions that could be the cause of violating monitors along
the I-95 corridor. Kentucky's SIP also mentions two additional coastal
monitor sites (Westport Sherwood and Stratford Point Lighthouse)
located less than three miles from the I-95 corridor that also show a
pattern of ozone violations. Kentucky raises similar points regarding
the effect of mobile source emissions along the I-95 corridor in
Maryland near the Edgewood receptor. Further, Kentucky asserts that
both the Connecticut and Maryland receptor sites may be particularly
impacted by unique coastal conditions associated with the Long Island
Sound and the Chesapeake Bay. While it is true that both of these
monitors are affected by coastal meteorological conditions such as
complex land-water wind flows and mixing heights, a large portion of
anthropogenic ozone at these locations is the result of transport from
upwind states. In addition, as noted above, EPA's most recent modeling
shows that Kentucky is linked to a receptor in Bucks County,
Pennsylvania which is inland and not influenced by coastal meteorology.
The relevance of the points raised by Kentucky regarding the
HYSPLIT back trajectories related to the evaluation of Kentucky's good
neighbor obligations is not clear. As already discussed, the statute
and the case law (particularly the holdings in Wisconsin and Maryland)
make clear that good neighbor obligations are not merely supplementary
to or deferable until after local emission reductions are achieved.
Further, all of the receptors to which Kentucky is linked are heavily
impacted by upwind state emissions in addition to local sources and
conditions. The Wisconsin decision's holding regarding international
contribution (discussed in section III.A) is equally applicable to an
upwind state's claims that some other state's emissions, or local
emissions, are ``more to blame'' than its own emissions. See 938 F.3d
303 at 323-25 (``an upwind State can `contribute' to downwind
nonattainment even if its emissions are not the but-for cause'').
5. Evaluation of Kentucky's Approach to Maintenance Receptors
Kentucky's SIP argues that states linked only to maintenance
receptors should be held to less stringent standards of emissions
reductions compared to states linked to a nonattainment receptor. Thus,
as the Edgewood monitor was identified as a maintenance receptor in
EPA's March 2018 memorandum modeling, the Commonwealth asserts that no
further reductions from Kentucky sources other than on-the-books
controls should be required. Although the Harford monitor is no longer
linked to Kentucky based on EPA's updated modeling,\67\ emissions from
the Commonwealth are linked to the Bucks County, Pennsylvania (ID:
420170012) maintenance-only receptor. Additionally, MOG argues that
states should be absolved from additional emissions controls to address
a maintenance monitor if the upwind state can show that either the
monitor is likely to remain in attainment for a period of 10 years or
that the upwind state's emissions will not increase for 10 years after
the attainment date.\68\
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\67\ See Table 1, shown previously in this notice.
\68\ Kentucky did not rely on MOG's proposed approach in its SIP
submittal, therefore EPA does not comprehensively evaluate MOG's
suggestion. However, EPA's definition of maintenance receptors
already accounts for, and projects whether, receptors may have
trouble attaining the NAAQS, through the use of projected maximum
design values in the relevant analytic year. Further, EPA's modeling
of the relevant analytic year also already accounts for projected
emissions trends of the upwind state (among others) and may (and
often does) identify a linkage to areas that may struggle to
maintain the NAAQS despite an overall declining emissions trend.
This is not surprising. First, most maintenance receptors in EPA's
projections are currently measuring nonattainment, meaning that,
despite projecting improved air quality in the future analytic year,
the receptor location is currently, and may continue to be, near the
level of the NAAQS. Second, ozone levels are influenced by
meteorological variability and thus high ozone levels may persist
despite declining emissions as a result of recurring or worsening
ozone-conducive atmospheric conditions (e.g., higher temperatures).
It is unclear how MOG's approach would account for this variability
or ensure that projected emissions reductions from linked states are
rendered certain and enforceable.
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Under the D.C. Circuit's decision in North Carolina, states and EPA
are required to give independent significance to the ``interference
with maintenance'' prong of section 110(a)(2)(D)(i)(I). See 531 F.3d at
910. Since CSAPR, EPA's nationally consistent policy framework for
addressing interstate ozone transport has given meaning to this prong
through a separate definition of maintenance receptors at Step 1 of the
4-step interstate transport framework. For states linked only to those
receptors, EPA has found it appropriate to apply an emissions control
solution that is uniform with the strategy applied for states that are
linked to nonattainment receptors. See 76 FR at 48271. EPA's approach
to addressing interference with maintenance under prong 2 for ozone
NAAQS has been upheld twice. See EME Homer City Generation, L.P., 795
F.3d at 136; Wisconsin, 938 F.3d at 325-27. See also 86 FR at 23054
(April 30, 2021).\69\
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\69\ In the main text of its SIP submittal conclusion regarding
interstate transport, Kentucky incorrectly attributes statements
regarding the ``interfere with maintenance'' prong to the U.S.
Supreme Court. See Submittal at 45-46. A footnote, however,
correctly attributes this language to the D.C. Circuit's original
opinion in EME Homer City v EPA, 696 F.3d 7 (D.C. Cir. 2012). This
decision was reversed and remanded by the Supreme Court, and on
remand, the D.C. Circuit affirmed EPA's approach to implementing
prong 2, see 795 F.3d at 136.
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Particularly given this context, Kentucky's SIP submission does not
provide information sufficient to support less stringent standards of
emissions reductions than would result from EPA's historical approach
of addressing emissions activities from upwind states that are linked
to maintenance-only receptors. The Commonwealth does not explain how
the obligations of upwind states linked to maintenance-only receptors
should be treated differently than the obligations of upwind states
linked to nonattainment receptors.
Further, EPA believes it would be inconsistent with the CAA for EPA
to identify receptors that are at risk of NAAQS violations given
certain conditions due to transported upwind emissions and then not
prohibit the emissions that place the receptor at risk. The Supreme
Court held that it was a permissible interpretation of the statute to
apportion responsibility for states
[[Page 9515]]
linked to nonattainment receptors considering ``both the magnitude of
upwind States' contributions and the cost associated with eliminating
them.'' EME Homer City, 134 S. Ct. at 1606. It is equally reasonable
and permissible to use these factors to apportion responsibility among
upwind states linked to maintenance receptors because the goal in both
instances is to prohibit the ``amounts'' of pollution that will either
significantly contribute to nonattainment or interfere with maintenance
of the NAAQS downwind. EPA's updated modeling indicates that the
Commonwealth is still linked to downwind nonattainment and maintenance
receptors for the 2015 8-hour ozone standard. Consequently, EPA
believes Kentucky's assertion that upwind states linked to maintenance-
only receptors should be held to less stringent standards of emissions
reductions (as compared to states linked to a nonattainment receptor)
is also inappropriate for new downwind linkages.
6. Evaluation of Weighted Step 3 Approach
Although Kentucky did not adopt this approach in its SIP submittal,
the MOG materials Kentucky appended provided arguments suggesting a
``weighted'' approach to Step 3 similar to an approach that
stakeholders had identified to EPA (as listed in Attachment A to EPA's
March 2018 memorandum). Under this approach, upwind-state emission
reduction obligations would be allocated in proportion to the size of
their contribution to downwind nonattainment. MOG determined the
proportional reduction requirement associated with the relative
significant contribution from each upwind state to the Harford County,
Maryland monitor including Kentucky, which resulted in an additional
emission reduction obligation for Kentucky of 0.02 ppb, as MOG proposed
would be the appropriate proportion of reductions necessary for
attainment at the Harford receptor. This approach would have imposed
additional emissions reductions for Kentucky sources. Kentucky's final
SIP did not consider MOG's proposal, and did not provide an explanation
for why it was rejecting this approach to allocating upwind emission
reductions, even though it appended this recommendation to its SIP
submittal.
In summary, EPA has newly available information that confirms
sources in Kentucky are linked to downwind air quality problems for the
2015 8-hour ozone standard. Kentucky's SIP submittal did not include an
accounting of emissions sources and activity in the Commonwealth along
with an analysis of potential NOX emissions control
technologies, their associated costs, estimated emissions reductions,
and downwind air quality improvements. Nor did Kentucky present an
alternative approach to assess which of its emissions should be deemed
``significant.'' EPA proposes to find that Kentucky's analysis--
including reliance on on-the-books state and Federal measures
(including prior CSAPR programs) and claimed on-the-way emission
reductions, as well as other air quality, emissions, and geographic
factors--is insufficient to support the Commonwealth's claim that its
SIP adequately prohibits emissions within Kentucky in a manner
sufficient to address the State's interstate transport obligations for
the 2015 8-hour ozone.
E. Evaluation of Information Provided by Kentucky Regarding Step 4
Step 4 of the 4-step interstate transport framework calls for
development of permanent and federally enforceable control strategies
to achieve the emissions reductions determined to be necessary at Step
3 to eliminate significant contribution to nonattainment or
interference with maintenance of the NAAQS. Kentucky indicates that
certain upcoming planned fuel switches or shutdowns at EGUs will occur
before the end of 2023, for which Kentucky cites a press release and a
closure plan developed by each plant's parent company.\70\ As discussed
in section III.D., Kentucky's analysis is insufficient to demonstrate
that these reductions are sufficient to address the Commonwealth's
interstate transport obligations; however, the Commonwealth also did
not provide a separate SIP revision to ensure the reductions were
permanent and enforceable. As a result, EPA proposes to disapprove
Kentucky's January 11, 2019, submittal on the separate, additional
basis that the Commonwealth has not developed permanent and enforceable
emissions reductions necessary to meet the obligations of CAA section
110(a)(2)(d)(i)(I).
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\70\ Pointing to anticipated upcoming emission reductions, even
if they were not included in the analysis at Steps 1 and 2, is not
sufficient as a Step 3 analysis, for the reasons discussed in
section III.C. In this section, EPA explain that to the extent such
anticipated reductions are not included in the SIP and rendered
permanent and enforceable, reliance on such anticipated reductions
is also insufficient at Step 4.
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F. Conclusion
Based on EPA's evaluation of Kentucky's SIP submission, EPA is
proposing to find that the interstate transport portion of Kentucky's
January 11, 2019, SIP submission addressing CAA section
110(a)(2)(D)(i)(I) does not meet the Commonwealth's interstate
transport obligations because it fails to contain the necessary
provisions to eliminate emissions that will contribute significantly to
nonattainment or interfere with maintenance of the 2015 8-hour ozone
NAAQS in any other state.
IV. Proposed Action
EPA is proposing to disapprove the 2015 8-hour ozone good neighbor
interstate transport SIP revision from Kentucky, dated January 11,
2019. Under CAA section 110(c)(1), if finalized, this disapproval would
establish a 2-year deadline for EPA to promulgate a FIP for Kentucky to
address the CAA section 110(a)(2)(D)(i)(I) interstate transport
requirements pertaining to significant contribution to nonattainment
and interference with maintenance of the 2015 8-hour ozone NAAQS in
other states, unless EPA approves a SIP that meets these requirements.
However, under the CAA, a good neighbor SIP disapproval does not start
a mandatory sanctions clock.
V. Statutory and Executive Order Reviews
A. Executive Order 12866: Regulatory Planning and Review and Executive
Order 13563: Improving Regulation and Regulatory Review
This proposed action is not a significant regulatory action and was
therefore not submitted to the Office of Management and Budget for
review.
B. Paperwork Reduction Act (PRA)
This proposed action does not impose an information collection
burden under the PRA because it does not contain any information
collection activities.
C. Regulatory Flexibility Act (RFA)
This action merely proposes to disapprove a SIP submission as not
meeting the CAA for Kentucky. EPA certifies that this proposed rule
will not have a significant economic impact on a substantial number of
small entities under the RFA (5 U.S.C. 601 et seq.).
D. Unfunded Mandates Reform Act (UMRA)
This proposed 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 proposed action imposes no
enforceable duty on any state, local, or tribal governments or the
private sector.
[[Page 9516]]
E. Executive Order 13132: Federalism
This proposed 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: Consultation and Coordination With Indian
Tribal Governments
This proposed action does not have tribal implications as specified
in Executive Order 13175. This proposed action does not apply on any
Indian reservation land, any other area where EPA or an Indian tribe
has demonstrated that a tribe has jurisdiction, or non-reservation
areas of Indian country. Thus, Executive Order 13175 does not apply to
this action.
G. Executive Order 13045: Protection of Children From Environmental
Health Risks and Safety Risks
EPA interprets Executive Order 13045 as applying only to those
regulatory actions that concern environmental health or safety risks
that 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 proposed action is not subject to Executive
Order 13045 because it merely proposes to disapprove a SIP submission
from Kentucky as not meeting the CAA.
H. Executive Order 13211, Actions That Significantly Affect Energy
Supply, Distribution or Use
This proposed 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
This proposed rulemaking does not involve technical standards.
J. Executive Order 12898: Federal Actions To Address Environmental
Justice in Minority Populations and Low-Income Populations
EPA believes the human health or environmental risk addressed by
this action will not have potential disproportionately high and adverse
human health or environmental effects on minority, low-income or
indigenous populations. This action merely proposes to disapprove a SIP
submission as not meeting the CAA.
K. CAA Section 307(b)(1)
Section 307(b)(1) of the CAA governs judicial review of final
actions by EPA. This section provides, in part, that petitions for
review must be filed in the D.C. Circuit: (i) When the agency action
consists of ``nationally applicable regulations promulgated, or final
actions taken, by the Administrator,'' or (ii) when such action is
locally or regionally applicable, if ``such action is based on a
determination of nationwide scope or effect and if in taking such
action the Administrator finds and publishes that such action is based
on such a determination.'' For locally or regionally applicable final
actions, the CAA reserves to EPA complete discretion whether to invoke
the exception in (ii).\71\
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\71\ In deciding whether to invoke the exception by making and
publishing a finding that an action is based on a determination of
nationwide scope or effect, the Administrator takes into account a
number of policy considerations, including his judgment balancing
the benefit of obtaining the D.C. Circuit's authoritative
centralized review versus allowing development of the issue in other
contexts and the best use of agency resources.
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If EPA takes final action on this proposed rulemaking, the
Administrator intends to exercise the complete discretion afforded to
him under the CAA to make and publish a finding that the final action
(to the extent a court finds the action to be locally or regionally
applicable) is based on a determination of ``nationwide scope or
effect'' within the meaning of CAA section 307(b)(1). Through this
rulemaking action (in conjunction with a series of related actions on
other SIP submissions for the same CAA obligations), EPA interprets and
applies section 110(a)(2)(d)(i)(I) of the CAA for the 2015 8-hour ozone
NAAQS based on a common core of nationwide policy judgments and
technical analysis concerning the interstate transport of pollutants
throughout the continental U.S. In particular, EPA is applying here
(and in other proposed actions related to the same obligations) the
same, nationally consistent 4-step framework for assessing good
neighbor obligations for the 2015 8-hour ozone NAAQS. EPA relies on a
single set of updated, 2016-base year photochemical grid modeling
results of the year 2023 as the primary basis for its assessment of air
quality conditions and contributions at Steps 1 and 2 of that
framework. Further, EPA proposes to determine and apply a set of
nationally consistent policy judgments to apply the 4-step framework.
EPA has selected a nationally uniform analytic year (2023) for this
analysis and is applying a nationally uniform approach to nonattainment
and maintenance receptors and a nationally uniform approach to
contribution threshold analysis.\72\ For these reasons, the
Administrator intends, if this proposed action is finalized, to
exercise the complete discretion afforded to him under the CAA to make
and publish a finding that this action is based on one or more
determinations of nationwide scope or effect for purposes of CAA
section 307(b)(1).\73\
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\72\ A finding of nationwide scope or effect is also appropriate
for actions that cover states in multiple judicial circuits. In the
report on the 1977 Amendments that revised section 307(b)(1) of the
CAA, Congress noted that the Administrator's determination that the
``nationwide scope or effect'' exception applies would be
appropriate for any action that has a scope or effect beyond a
single judicial circuit. See H.R. Rep. No. 95-294 at 323, 324,
reprinted in 1977 U.S.C.C.A.N. 1402-03.
\73\ EPA may take a consolidated, single final action on all of
the proposed SIP disapproval actions with respect to obligations
under CAA section 110(a)(2)(D)(i)(I) for the 2015 8-hour ozone
NAAQS. Should EPA take a single final action on all such
disapprovals, this action would be nationally applicable, and EPA
would also anticipate, in the alternative, making and publishing a
finding that such final action is based on a determination of
nationwide scope or effect.
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List of Subjects in 40 CFR Part 52
Environmental protection, Air pollution control, Incorporation by
reference, Ozone.
Authority: 42 U.S.C. 7401 et seq.
Dated: February 3, 2022.
Daniel Blackman,
Regional Administrator, Region 4.
[FR Doc. 2022-02947 Filed 2-18-22; 8:45 am]
BILLING CODE 6560-50-P
