Air Plan Approval; Alabama; Birmingham Limited Maintenance Plan for the 2006 24-Hour PM2.5 NAAQS, 86303-86312 [2023-27297]

Agencies

• ENVIRONMENTAL PROTECTION AGENCY

[Federal Register Volume 88, Number 238 (Wednesday, December 13, 2023)]
[Proposed Rules]
[Pages 86303-86312]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-27297]


=======================================================================
-----------------------------------------------------------------------

ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[EPA-R04-OAR-2021-0367; FRL-11573-01-R4]


Air Plan Approval; Alabama; Birmingham Limited Maintenance Plan 
for the 2006 24-Hour PM2.5 NAAQS

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

-----------------------------------------------------------------------

SUMMARY: The Environmental Protection Agency (EPA) is proposing to 
approve a State implementation plan (SIP) revision submitted by the 
State of Alabama, through the Alabama Department of Environmental 
Management (ADEM), via a letter dated February 2, 2021. The SIP 
revision includes the 2006 24-hour fine particulate matter 
(PM2.5) national

[[Page 86304]]

ambient air quality standards (NAAQS) Limited Maintenance Plan (LMP) 
for the Birmingham, Alabama maintenance area (Birmingham Area or Area). 
The Birmingham 2006 24-hour PM2.5 maintenance area is 
comprised of Jefferson County, Shelby County, and a portion of Walker 
County. EPA is proposing to approve the Birmingham Area LMP because it 
provides for the maintenance of the 2006 24-hour PM2.5 NAAQS 
within the Birmingham Area through the end of the second 10-year 
portion of the maintenance period in 2034. The effect of this action 
would be to incorporate into the Alabama SIP certain commitments 
related to maintenance of the 2006 24-hour PM2.5 NAAQS in 
the Birmingham Area, making them federally enforceable. EPA is also 
starting the adequacy process, consistent with requirements in the 
transportation conformity rule, for this LMP.

DATES: Comments must be received on or before January 12, 2024.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R04-
OAR-2021-0367 at https://www.regulations.gov. Follow the online 
instructions for submitting comments. Once submitted, comments cannot 
be edited or removed from Regulations.gov. EPA may publish any comment 
received to its public docket. Do not submit electronically any 
information you consider to be Confidential Business Information (CBI) 
or other information whose disclosure is restricted by statute. 
Multimedia submissions (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). For additional submission methods, the full EPA public comment 
policy, information about CBI or multimedia submissions, and general 
guidance on making effective comments, please visit https://www2.epa.gov/dockets/commenting-epa-dockets.

FOR FURTHER INFORMATION CONTACT: Dianna Myers, 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. The telephone number is 
(404) 562-9207. Ms. Myers can also be reached via electronic mail at 
[email protected].

SUPPLEMENTARY INFORMATION:

Table of Contents

I. Summary of EPA's Action
II. Background
III. Alabama's SIP Submittal
IV. EPA's Evaluation of Alabama's SIP Submittal
    A. Attainment Emissions Inventory
    B. Maintenance Demonstration
    1. Evaluation of PM2.5 Air Quality Levels
    2. Stability of PM2.5 Levels
    C. Monitoring Network and Verification of Continued Attainment
    D. Contingency Plan
    E. Conclusion
V. Transportation Conformity
VI. General Conformity
VII. Proposed Action
VIII. Statutory and Executive Order Reviews

I. Summary of EPA's Action

    In accordance with the Clean Air Act (CAA or Act), EPA is proposing 
to approve the Birmingham Area LMP for the 2006 24-hour 
PM2.5 NAAQS, adopted by ADEM on February 2, 2021, and 
submitted by ADEM as a revision to the Alabama SIP under a cover letter 
with the same date.\1\ The Birmingham Area LMP is designed to maintain 
the 2006 24-hour PM2.5 NAAQS within the Birmingham Area 
through the end of the second 10-year portion of the maintenance period 
beyond redesignation. EPA is proposing to approve the plan because it 
meets all applicable requirements under CAA sections 110 and 175A. As a 
general matter, the Birmingham Area LMP relies on the same control 
measures and similar contingency measures to maintain the 2006 24-hour 
PM2.5 NAAQS during the second 10-year portion of the 
maintenance period as the maintenance plan submitted by ADEM for the 
first 10-year period, which is not a limited maintenance plan.
---------------------------------------------------------------------------

    \1\ EPA notes the Agency received the submittal on February 17, 
2021.
---------------------------------------------------------------------------

II. Background

    Fine particulate matter, particulate matter with an aerodynamic 
diameter of 2.5 microns or less, can be emitted directly into the 
atmosphere as a solid or liquid particle (``primary PM2.5'' 
or ``direct PM2.5'') or can be formed in the atmosphere as a 
result of various chemical reactions among precursor pollutants such as 
nitrogen oxides (NOX), sulfur oxides, volatile organic 
compounds (VOC), and ammonia (NH3) (``secondary 
PM2.5'').\2\ Epidemiological studies have shown 
statistically significant correlations between elevated levels of 
PM2.5 and premature mortality. Other important health 
effects associated with PM2.5 exposure include aggravation 
of respiratory and cardiovascular disease, changes in lung function, 
and increased respiratory complications, contributing to premature 
mortality and increased hospital admissions and emergency room visits. 
Individuals particularly sensitive to PM2.5 exposure include 
older adults, people with heart and lung disease, and children.\3\
---------------------------------------------------------------------------

    \2\ See 78 FR 3086 at 3090, 3121 (January 15, 2013).
    \3\ See id.; ``Fact Sheet Final Revisions to the National 
Ambient Air Quality Standards for Particle Pollution (Particulate 
Matter),'' September 21, 2006, accessible at: https://www.epa.gov/sites/production/files/2016-04/documents/20060921_standards_factsheet.pdf; 71 FR 61144, 61145 (October 17, 
2006).
---------------------------------------------------------------------------

    On July 18, 1997, EPA promulgated the first air quality standards 
for PM2.5. See 62 FR 38652. EPA promulgated a 24-hour 
standard of 65 [mu]g/m\3\, based on a 3-year average of the 98th 
percentile of 24-hour concentrations.\4\ On October 17, 2006, EPA 
revised the 24-hour NAAQS to 35 [mu]g/m\3\, based again on the 3-year 
average of the 98th percentile of 24-hour concentrations. See 71 FR 
61144.\5\ Under EPA regulations at 40 CFR part 50, the primary and 
secondary 2006 24-hour PM2.5 NAAQS are attained when the 3-
year average of the 98th percentile of 24-hour concentration, as 
determined in accordance with 40 CFR part 50, Appendix N, is less than 
or equal to 35 [mu]g/m\3\ at all relevant monitoring sites in the 
subject area over a 3-year period.
---------------------------------------------------------------------------

    \4\ In the same rulemaking, EPA promulgated an annual standard 
at a level of 15.0 micrograms per cubic meter ([mu]g/m\3\), based on 
a 3-year average of annual mean PM2.5 concentrations. See 
62 FR 38652.
    \5\ On January 15, 2013, and December 18, 2020, EPA retained the 
24-hour primary and secondary PM2.5 NAAQS at the 2006 
level of 35 [mu]g/m\3\. See 78 FR 3086 and 85 FR 82684.
---------------------------------------------------------------------------

    Following promulgation of a new revised NAAQS, EPA is required by 
the CAA to designate areas throughout the nation as attaining or not 
attaining the NAAQS. On November 13, 2009, EPA promulgated designations 
for the 2006 24-hour PM2.5 NAAQS, designating the Birmingham 
Area, which includes Jefferson County, Shelby County, and a portion of 
Walker County, as nonattainment for the 2006 24-hour PM2.5 
NAAQS based upon air quality data for calendar years 2006 through 2008. 
See 74 FR 58688. Under the CAA, States are also required to adopt and 
submit SIPs to implement, maintain, and enforce the NAAQS in designated 
nonattainment areas and throughout the State.
    A State may submit a request to redesignate a nonattainment area 
that is attaining the NAAQS, and, if the area has met the required 
criteria described in section 107(d)(3)(E) of the CAA, EPA may approve 
the redesignation to

[[Page 86305]]

attainment for the area.\6\ One of the criteria for redesignation is to 
have an approved maintenance plan under CAA section 175A. The 
maintenance plan must demonstrate that the area will continue to 
maintain the NAAQS for the period extending 10 years after 
redesignation, and it must contain such additional measures as 
necessary to ensure maintenance and such contingency provisions as 
necessary to assure that violations of the NAAQS will be promptly 
corrected. Eight years after the effective date of redesignation, the 
State must also submit a second maintenance plan to ensure ongoing 
maintenance of the NAAQS for an additional ten years pursuant to CAA 
section 175A(b) (i.e., ensuring maintenance for 20 years after 
redesignation).
---------------------------------------------------------------------------

    \6\ Section 107(d)(3)(E) of the CAA sets out the requirements 
for redesignating a nonattainment area to attainment. They include 
attainment of the NAAQS, full approval of the applicable SIP 
pursuant to CAA section 110(k), determination that improvement in 
air quality is a result of permanent and enforceable reductions in 
emissions, demonstration that the state has met all applicable 
section 110 and part D requirements, and a fully approved 
maintenance plan under CAA section 175A.
---------------------------------------------------------------------------

    In 2009, the Birmingham Area was designated as nonattainment for 
the 2006 24-hour PM2.5 NAAQS. On June 17, 2010, ADEM 
submitted to EPA a request to redesignate the Birmingham Area to 
attainment for the 2006 24-hour PM2.5 NAAQS. This submittal 
included a plan to provide for maintenance of the 2006 24-hour 
PM2.5 NAAQS in the Birmingham Area through 2024 as a 
revision to the Alabama SIP. On September 20, 2010, EPA issued a clean 
data determination under the Agency's Clean Data Policy based upon 
complete, quality assured, quality controlled, and certified ambient 
air monitoring data for the years 2007-2009 showing that the Birmingham 
Area had monitored attainment of the 2006 24-hour PM2.5 
NAAQS. See 75 FR 57186. Subsequently, on January 25, 2013, EPA approved 
the Birmingham Area's maintenance plan and the State's request to 
redesignate the Birmingham Area to attainment for the 2006 24-hour 
PM2.5 NAAQS. See 78 FR 5306.
    EPA has published long-standing guidance for States on developing 
maintenance plans.\7\ The Calcagni Memo provides that States may 
generally demonstrate maintenance by either performing air quality 
modeling to show that the future mix of sources and emission rates will 
not cause a violation of the NAAQS or by showing that projected future 
emissions of a pollutant and its precursors will not exceed the level 
of emissions during a year when the area was attaining the NAAQS (i.e., 
attainment year inventory). See Calcagni Memo at 9. EPA clarified in 
subsequent guidance memos that certain areas could meet the CAA section 
175A requirement to provide for maintenance by showing that the area 
was unlikely to violate the NAAQS in the future, using information such 
as the area's design value \8\ being significantly below the standard 
and the area having a historically stable design value.\9\ EPA refers 
to a maintenance plan containing this streamlined demonstration as an 
LMP, and in guidance, EPA has discussed certain criteria that it 
intends to evaluate, including consistency with EPA regulations along 
with other information as is relevant, in determining if this option is 
appropriate for an area.
---------------------------------------------------------------------------

    \7\ See Memorandum from John Calcagni, Director, Air Quality 
Management Division, EPA Office of Air Quality Planning and 
Standards, ``Procedures for Processing Requests to Redesignate Areas 
to Attainment,'' September 4, 1992 (Calcagni Memo). A copy of this 
guidance is available in the docket for this proposed rulemaking.
    \8\ The 24-hour PM2.5 design value for a monitoring 
site is the 3-year average of the annual 98th-percentile 24-hour 
average PM2.5 concentrations. The design value for a 
PM2.5 nonattainment area is the highest design value of 
any monitoring site in the area.
    \9\ See ``Limited Maintenance Plan Option for Nonclassifiable 
Ozone Nonattainment Areas,'' from Sally L. Shaver, Office of Air 
Quality Planning and Standards (OAQPS), dated November 16, 1994; 
``Limited Maintenance Plan Option for Nonclassifiable CO 
Nonattainment Areas,'' from Joseph Paisie, OAQPS, dated October 6, 
1995; ``Limited Maintenance Plan Option for Moderate PM10 
Nonattainment Areas,'' from Lydia Wegman, OAQPS, dated August 9, 
2001 (2001 PM10 LMP Guidance); and Guidance on the 
Limited Maintenance Plan Option for Moderate PM2.5 
Nonattainment Areas and PM2.5 Maintenance Areas (2022 
PM2.5 LMP Guidance). Copies of these guidance memoranda 
can be found in the docket for this proposed rulemaking.
---------------------------------------------------------------------------

    EPA has interpreted CAA section 175A as permitting the LMP option 
because section 175A of the Act does not define how areas may provide 
for maintenance, and in EPA's experience implementing the various 
NAAQS, areas that qualify for an LMP and have approved LMPs have 
rarely, if ever, experienced subsequent violations of the NAAQS. As 
noted in EPA's LMP guidance, States seeking an LMP must still submit 
the other maintenance plan elements outlined in the Calcagni Memo, 
including: an attainment emissions inventory, provisions for the 
continued operation of the ambient air quality monitoring network, 
verification of continued attainment, and a contingency plan in the 
event of a future violation of the NAAQS. Moreover, a State seeking an 
LMP as its section 175A maintenance plan must submit it as a revision 
to its SIP, with all attendant notice and comment procedures. While the 
LMP guidance memoranda were originally written with respect to certain 
NAAQS,\10\ EPA has extended the LMP interpretation of section 175A to 
certain other NAAQS and pollutants not specifically covered by the 
previous guidance memos.\11\
---------------------------------------------------------------------------

    \10\ Prior memos addressed unclassifiable areas under the 1-hour 
ozone NAAQS, nonattainment areas for the PM10 
(particulate matter with an aerodynamic diameter less than 10 
microns) NAAQS, and nonattainment areas for the carbon monoxide (CO) 
NAAQS.
    \11\ See, e.g., 79 FR 41900 (July 18, 2014) (approval of second 
ten-year LMP for Grant County 1971 sulfur dioxide (SO2) 
maintenance area).
---------------------------------------------------------------------------

    At the time ADEM was developing its February 2, 2021, SIP revision, 
EPA had not developed specific LMP guidance for PM2.5, and 
ADEM consulted with the Agency in extending the rationale from the 2001 
PM10 LMP Guidance, which was written for particulate matter 
with an aerodynamic diameter of 10 microns or less (PM10), 
to the PM2.5 maintenance plan.\12\ Accordingly, ADEM 
prepared its second maintenance plan submission in accordance with the 
2001 PM10 LMP Guidance. Since the time of the February 2, 
2021, submittal, EPA has released LMP guidance for PM2.5. 
Specifically, on October 27, 2022, EPA published clarifying guidance 
that focuses on the distinctions that are relevant specifically for 
PM2.5 LMPs for Moderate PM2.5 Nonattainment and 
PM2.5 Maintenance Areas.\13\ The 2022 PM2.5 LMP 
Guidance applies the 2001 Limited Maintenance Plan Option for Moderate 
PM10 Nonattainment Areas guidance for PM2.5 LMP 
submissions, except for the specific topics where the 2001 guidance is 
superseded. Therefore, EPA has evaluated the February 2, 2021, 
submittal in light of the criteria discussed in the 2022 
PM2.5 LMP Guidance, as well as the relevant statutory and 
regulatory requirements.
---------------------------------------------------------------------------

    \12\ As discussed further below, ADEM prepared its second 
maintenance plan submission following the 2001 PM10 LMP 
Guidance.
    \13\ A copy is available in the docket for this proposed action 
and also available via https://www.epa.gov/system/files/documents/2023-03/PM%202.5%20Limited%20Maintenance%20Plan%20Guidance.pdf.
---------------------------------------------------------------------------

    EPA is proposing to approve the Birmingham Area LMP because the 
State has made a showing, consistent with EPA's current 
PM2.5 LMP guidance, that the Birmingham Area's 
PM2.5 concentrations are well below the 2006 24-hour 
PM2.5 NAAQS and have been historically stable, and that it 
has met the other maintenance plan requirements. EPA's evaluation of 
the Birmingham Area LMP is presented in Section IV of this notice of 
proposed rulemaking (NPRM).

[[Page 86306]]

III. Alabama's SIP Submittal

    Under CAA section 175A(b), States must submit a revision to the 
first maintenance plan eight years after redesignation to provide for 
maintenance of the NAAQS for ten additional years following the end of 
the first 10-year period. Accordingly, on February 2, 2021, Alabama 
submitted a second maintenance plan for the Birmingham Area that shows 
that the Area is expected to remain in attainment of the 2006 24-hour 
PM2.5 NAAQS through 2034, i.e., through the end of the full 
20-year maintenance period.
    In recognition of the continuing record of air quality monitoring 
data showing ambient 24-hour PM2.5 concentrations in the 
Birmingham Area well below the 2006 24-hour PM2.5 NAAQS, 
ADEM chose the LMP option for the development of a second 2006 24-hour 
PM2.5 NAAQS maintenance plan. On February 2, 2021, ADEM 
adopted the second 10-year maintenance plan for the 2006 24-hour 
PM2.5 NAAQS and submitted the Birmingham Area LMP to EPA as 
a revision to the Alabama SIP.
    The February 2, 2021, submittal includes the LMP, air quality data 
and other information demonstrating qualification for the LMP, 
emissions inventory information, and appendices, as well as 
certification of adoption of the plan by ADEM. Appendices to the plan 
include a copy of the 2001 PM10 LMP Guidance, supplemental 
information on ADEM's mobile source emissions analysis, emissions 
inventory development data, and qualifying calculations in accordance 
with the 2001 PM10 LMP Guidance. The submittal also includes 
documentation of notice, hearing, and public participation prior to 
adoption of the plan by ADEM on February 2, 2021. The Birmingham Area 
LMP relies on the same emission reduction strategy and other already-
implemented measures as the Area's first 10-year maintenance plan, 
which provides for the maintenance of the 2006 24-hour PM2.5 
NAAQS through 2024. Specifically, the Birmingham Area LMP relies on the 
following measures: the continuation of programs such as the local 
Jefferson County and Shelby County burn bans, prioritizing funding for 
diesel emissions reduction projects within the Birmingham Area, 
continued implementation of Federal measures (for example, Tier 3 Motor 
Vehicle Emission and Fuel Standards,\14\ and interstate transport rules 
\15\), and emission reductions achieved and documented for the first 
CAA section 175A maintenance plan.\16\ Since Alabama submitted its 
maintenance plan for the first 10-year portion of the maintenance 
period, other changes that have decreased PM2.5 and 
precursor emissions in the Area have taken place, as noted in the 
February 2, 2021, submittal. Examples include the permanent shutdown of 
Units 1-5 at the Tennessee Valley Authority's Colbert Plant, the 
permanent shutdown of Alabama Power Company's Plant Gorgas, the 
installation of a baghouse with an electrostatic precipitator at 
Alabama Power Company's Plant Gaston, and the conversion of the coal-
fired units to natural gas at Alabama Power Company's Greene County 
Steam Plant.\17\
---------------------------------------------------------------------------

    \14\ See 79 FR 23414 (April 28, 2014). The February 17, 2021, 
submittal lists this as ``Tier IV,'' which is an error, as only Tier 
3 standards have been set for on-road mobile source emissions 
standards. EPA understands this to be in reference to the latest 
emissions standards, referred to as ``Tier 3.''
    \15\ See, e.g., 63 FR 57355 (October 27, 1998).
    \16\ See also 78 FR 5306 (January 25, 2013), 76 FR 70091 
(November 10, 2011), and the submittal at docket ID EPA-R04-OAR-
2011-0043.
    \17\ See also EPA docket EPA-HQ-OAR-2017-0003 and item EPA-HQ-
OAR-2017-0003-0213 supporting EPA's air quality designations for the 
2010 1-hour SO2 NAAQS.
---------------------------------------------------------------------------

IV. EPA's Evaluation of Alabama's SIP Submittal

    EPA has reviewed the Birmingham Area LMP, which is designed to 
maintain the 2006 24-hour PM2.5 NAAQS within the Birmingham 
Area through the end of the 20-year period beyond redesignation, as 
required under CAA section 175A(b). The following is a summary of EPA's 
interpretation of the section 175A requirements \18\ and EPA's 
evaluation of how each requirement is met.
---------------------------------------------------------------------------

    \18\ See Calcagni Memo.
---------------------------------------------------------------------------

A. Attainment Emissions Inventory

    For maintenance plans, a State should develop a comprehensive, 
accurate inventory of actual emissions for an attainment year to 
identify the level of emissions which is sufficient to maintain the 
NAAQS. A State should develop this inventory consistent with EPA's most 
recent guidance on emissions inventory development. For the 24-hour 
PM2.5 NAAQS, the inventory should be based on representative 
daily emissions of direct PM2.5 and precursor emissions, 
including SO2, NOX, VOC, and NH3. The 
Birmingham Area LMP includes a PM2.5 attainment inventory 
for the Birmingham Area with emissions from 2017. Table 1 presents a 
summary of the inventory for 2017 contained in the LMP for 
PM2.5 and precursor emissions.

                                      Table 1--2017 SO2, NOX, PM2.5, VOC, and NH3 Emissions for the Birmingham Area
                                                                       [Tons/day]
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                             Non-point        On-road         Nonroad
                                                           Point  source      source       mobile source   mobile source       Event           Total
--------------------------------------------------------------------------------------------------------------------------------------------------------
SO2.....................................................           52.95             0.5            0.27            0.02            0.14           53.88
NOX.....................................................           73.06           10.02           27.96            9.44            0.32           120.8
PM2.5...................................................             9.0           13.94            0.80            1.07            1.17           25.98
VOC.....................................................             9.4          171.17           12.91            7.75            2.99          204.22
NH3.....................................................            0.40            1.77            0.95            0.02            0.16            3.30
--------------------------------------------------------------------------------------------------------------------------------------------------------

    The Attainment Emissions Inventory section of the Birmingham Area 
LMP describes the methods, models, and assumptions used to develop the 
attainment inventory. As described in the Attainment Emissions 
Inventory section of the LMP, ADEM relied on the 2017 National 
Emissions Inventory (NEI) for point source, non-point (or area source), 
and event emissions (which typically consist of activities such as 
wildfires), except as described below.\19\
---------------------------------------------------------------------------

    \19\ Documentation and data for the 2017 NEI can be accessed via 
the following website: https://www.epa.gov/air-emissions-inventories/2017-national-emissions-inventory-nei-data.
---------------------------------------------------------------------------

    Nonroad mobile source emissions were, in part, estimated using the 
latest version of the EPA's motor vehicle emissions model, MOVES3 
(which provides the ability to estimate nonroad emissions from 
agricultural, commercial, mining, industrial, and

[[Page 86307]]

recreational equipment, and commercial and residential lawn and garden 
equipment, among others). Locomotives, aircraft, and marine nonroad 
sources are not included in MOVES, and ADEM relied on EPA-generated 
emissions for these sectors.\20\ ADEM estimated on-road mobile source 
emissions using MOVES3 and local data such as vehicle type, activity, 
and vehicle speeds from the Birmingham metropolitan planning 
organization (MPO) to estimate vehicular emissions for 2017. ADEM's 
estimates for vehicles reflect emissions inventories and ancillary data 
files used for emissions modeling, as well as the meteorological, 
initial condition, and boundary condition files needed to run the air 
quality model.
---------------------------------------------------------------------------

    \20\ EPA developed emissions for these sectors based on AP-42 
emissions factors, and information supplied by the Eastern Regional 
Technical Advisory Committee for locomotives and Federal Aviation 
Administration's Aviation Environmental Design Tool. See 2017 
National Emissions Inventory: January 2021 Updated Release, 
Technical Support Document available via the following website: 
https://www.epa.gov/air-emissions-inventories/2017-national-emissions-inventory-nei-technical-support-document-tsd.
---------------------------------------------------------------------------

    Based on EPA's review of the methods, models, and assumptions used 
by Alabama to develop the inventory, as well as EPA's review of the 
2017 daily emissions data, EPA proposes to find that the Birmingham 
Area LMP includes a comprehensive, accurate inventory of actual 
PM2.5 and precursor emissions in attainment year 2017 and 
proposes to conclude that this is acceptable for the purposes of a 
maintenance plan under CAA section 175A(b).

B. Maintenance Demonstration

    The maintenance demonstration requirement is considered to be 
satisfied in an LMP if the State can provide sufficient weight of 
evidence indicating that air quality in the area is well below the 
level of the NAAQS, that past air quality trends have been shown to be 
stable, and that the probability of the area experiencing a violation 
during the second 10-year maintenance period is low.\21\ These criteria 
are evaluated below with regard to the Birmingham Area. As noted in 
Section II of this NPRM, EPA has evaluated ADEM's submittal and, 
considering the submittal's contents and EPA's conclusions based 
thereon, finds the LMP to be consistent with EPA's current LMP guidance 
for PM2.5 Maintenance Areas. Although ADEM developed the 
Birmingham Area LMP in accordance with the 2001 PM10 LMP 
Guidance, the LMP is nonetheless consistent with the portions of the 
2022 PM2.5 LMP Guidance that superseded the 2001 
PM10 LMP Guidance.
---------------------------------------------------------------------------

    \21\ See 2022 PM2.5 LMP Guidance; see also 2001 
p.m.10 LMP Guidance; ``Limited Maintenance Plan Option 
for Nonclassifiable Ozone Nonattainment Areas'' from Sally L. 
Shaver, Office of Air Quality Planning and Standards (OAQPS), dated 
November 16, 1994; and ``Limited Maintenance Plan Option for 
Nonclassifiable CO Nonattainment Areas'' from Joseph Paisie, OAQPS, 
dated October 6, 1995.
---------------------------------------------------------------------------

1. Evaluation of PM2.5 Air Quality Levels
    To attain the 2006 24-hour PM2.5 NAAQS, the three-year 
average of the 98th percentile 24-hour average PM2.5 
concentrations (design value) at each monitor within an area must not 
exceed 35 [mu]g/m\3\. Table 2 includes the Area-wide monitor design 
values for the 2006 24-hour PM2.5 NAAQS from EPA's Air 
Quality System (AQS) for the period 2015-2019, which covers the overall 
period from 2013-2019.\22\
---------------------------------------------------------------------------

    \22\ 40 CFR 58.11(e) requires agencies to assess data from Class 
III PM2.5 Federal equivalent methods (FEMs) operating in 
their network alongside collocated Federal reference methods (FRMs) 
in accordance with table C-4 to subpart C of 40 CFR part 53. The 
Jefferson County Department of Health (JCDH) submitted a 
demonstration on November 28, 2022, showing that the FEM operating 
at AQS site 01-073-0023 did not meet these performance criteria and 
therefore should not be used for comparison to the NAAQS. EPA 
approved this demonstration on February 2, 2023. As stated in EPA's 
approval (which is included in the docket for this proposed 
rulemaking), JCDH included its demonstration and EPA's approval 
thereof in the 2023 network plan that was posted for public comment. 
See the docket for this proposed rulemaking for more information.

          Table 2--2015-2019 Design Values (DV) ([mu]g/m\3\) for the 2006 24-Hour PM2.5 NAAQS at Monitoring Sites in the Birmingham Area a b c
--------------------------------------------------------------------------------------------------------------------------------------------------------
                AQS site ID                           Location               2013-2015       2014-2016       2015-2017       2016-2018       2017-2019
--------------------------------------------------------------------------------------------------------------------------------------------------------
01-073-0023...............................  North Birmingham............              23              23              22              21          \d\ 20
01-073-1005...............................  McAdory.....................          \e\ 20          \e\ 18              18              17              18
01-073-1010...............................  Leeds.......................              20              19              17              18              18
01-073-2003...............................  Wylam.......................              20              19              18              18              17
--------------------------------------------------------------------------------------------------------------------------------------------------------
\a\ The Metropolitan Statistical Area (MSA) is required to have a minimum of three PM2.5 monitoring sites. The MSA still maintains five regulatory PM2.5
  monitoring sites, offering adequate coverage of the MSA.
\b\ Some of the data in this table is different than that transmitted in the February 2, 2021, submittal. EPA queried AQS to substitute the data for the
  2014-2016 design values for the Leeds, McAdory, and Wylam sites and understands these differences to be the result of typographical errors.
\c\ There is one additional monitor in Jefferson County recording PM2.5 data. The Arkadelphia/Near Road site in AQS with ID 01-073-2059, identified as
  the West Birmingham monitor in the February 2, 2021, SIP revision, began recording data to AQS in calendar year 2014, so 2014-2016 comprises the first
  period with three full years of data to calculate a DV. However, until Quarter 3 of 2020, data collected were incomplete because the Federal reference
  method monitor was operating on a 1-in-6-day sampling frequency rather than a 1-in-3-day sampling frequency as required by 40 CFR 58.12(d). The
  incomplete data means that resulting calculated DVs are invalid. Accordingly, those data are not presented here or included in further analysis.
\d\ The 2017-2019 DV for the North Birmingham site differs from the DV submitted in the February 2, 2021, SIP revision because the updated value
  presented in Table 2 reflects EPA-approved exclusion of data from one monitor at the site and utilization of data recorded at a collocated monitor for
  NAAQS-comparison purposes.
\e\ These data are incomplete due to the need to relocate the monitor in the first quarter of 2014, and the resulting DVs for 2013-2015 and 2014-2016
  are invalid.

    From the available data in Table 2, the representative complete DV 
for the Birmingham Area was the North Birmingham monitor DV for each 
three-year period. The highest complete DV in this time period is 23 
[micro]g/m\3\, which is 66% of the 24-hour NAAQS. The most recent 
official DVs are for 2020-2022 and are as follows: North Birmingham, 17 
[mu]g/m\3\; McAdory, 17 [mu]g/m\3\; Leeds, 18 [mu]g/m\3\; and Wylam, 18 
[mu]g/m\3\. These most recent data are slightly lower than those 
presented in Table 2 and continue to show the general downward 
trend.\23\
---------------------------------------------------------------------------

    \23\ For more information on the air quality data, see 
additional information in the document titled ``Technical Support 
Document for EPA's Notice of Proposed Rulemaking: Air Plan Approval; 
Alabama; Birmingham Limited Maintenance Plan for the 2006 24-Hour 
PM2.5 NAAQS'' (Birmingham TSD) with the file name ``AL-
124 TSD_Alabama Limited Maintenance Plan for 2006 
PM2.5.pdf'' in the docket for this proposed rulemaking.

---------------------------------------------------------------------------

[[Page 86308]]

    To qualify for the LMP option pursuant to EPA's 2022 
PM2.5 LMP Guidance, a State must analyze the design value 
(DV) trends to determine a critical design value (CDV), which is 
typically calculated based on the five-year average of the most recent 
DVs for the area and the statistical variation of the average DV. If 
each site in the maintenance area has an average design value (ADV) 
that is less than the CDV, it would demonstrate that the area has 
PM2.5 concentrations that will likely remain below the level 
of the standard in the future.
    The ADVs are used to determine the CDV for the area. See Table 3 
for relevant equations.
[GRAPHIC] [TIFF OMITTED] TP13DE23.001

    EPA notes that ADEM made use of a different calculation of the 
standard deviation than that shown in Table 3, which affects the 
calculations of the CV and the CDV. Specifically, ADEM made use of a 
population standard deviation, which treats the seven-year period and 
five resultant DVs as the entire set of available data needed to assess 
the stability of the DVs over time. The 2001 PM10 LMP 
Guidance, which ADEM followed when it developed the LMP, did not 
specify the approach for determining the standard deviation of DV data 
analyzed. However, the seven-year period and five resultant DVs used to 
assess the stability of the DVs over time are a subset, or sample, of 
all of the available historical data. Therefore, EPA considers the 
sample standard deviation, presented in Table 3, to be the most 
appropriate approach for determining the variability in the data.\24\
---------------------------------------------------------------------------

    \24\ See the February 2, 2021, submittal and the Birmingham TSD 
for more information on ADEM's calculations.
---------------------------------------------------------------------------

    ADEM calculated the CDV across the entire area to be 33.3 [mu]g/
m\3\ for the Birmingham Area, and the ADV across the Area to be 22.2 
[mu]g/m\3\. ADEM determined the CDV and ADV based on the controlling, 
or highest, DV across all monitoring sites in the Birmingham Area for 
each three-year period. EPA clarified in the 2022 PM2.5 LMP 
Guidance that the CDV approach is specifically intended to be conducted 
for each monitoring site in an area. Therefore, EPA has included the 
CDV and ADV calculations across each site in Table 4.

                                Table 4--Statistical Analysis of 2015-2019 DVs at Monitoring Sites in the Birmingham Area
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                           ADV  ([mu]g/                                    CDV  ([mu]g/       CDV-ADV
                AQS site ID                           Location                 m\3\)          [Sigma]           CV             m\3\)       ([mu]g/m\3\)
--------------------------------------------------------------------------------------------------------------------------------------------------------
01-073-0023...............................  North Birmingham............            21.8            1.30           0.060            32.1            10.3
01-073-1005...............................  McAdory.....................            18.2            1.10           0.060            32.0            13.8
01-073-1010...............................  Leeds.......................            18.4            1.14           0.062            32.0            13.6
01-073-2003...............................  Wylam.......................            18.4            1.14           0.062            32.0            13.6
--------------------------------------------------------------------------------------------------------------------------------------------------------

    EPA has calculated the CDVs over this time and across the Area, 
with the highest CDV being 32.1 [mu]g/m\3\ at the North Birmingham site 
and the lowest being 32.0 [mu]g/m\3\ at the other sites. The ADVs 
across the Birmingham Area in Table 4 are far below the CDVs, with the 
lowest margin between these values shown as 10.3 [mu]g/m\3\, so the 
Area qualifies for the LMP based on this portion of the analysis.
    The most recent DVs for 2018-2020, 2019-2021, and 2020-2022, 
available through EPA's AQS, do not alter the conclusions of the 
analysis conducted based on the 2015-2019 DVs. The available margins 
between the updated CDV and ADV for the 2018-2022 DVs covering the 
seven-year period from 2016-2022 for each site are as follows: North 
Birmingham, 11.8 [mu]g/m\3\; McAdory, 15.9 [mu]g/m\3\; Leeds, 15 [mu]g/
m\3\; and Wylam, 15.9 [mu]g/m\3\. These most recent margins between the 
calculated CDVs and ADVs are greater than those presented in Table 4, 
meaning the data at the monitoring sites more easily meet the criteria 
in the 2022 PM2.5 LMP Guidance.\25\
---------------------------------------------------------------------------

    \25\ See the Birmingham TSD for additional information.
---------------------------------------------------------------------------

    The 2022 PM2.5 LMP Guidance describes circumstances in 
which an LMP may be appropriate for a first and/or second 10-year 
maintenance plan.

[[Page 86309]]

For example, the 2022 PM2.5 LMP Guidance discusses how an 
LMP might be especially appropriate for second maintenance plans, 
considering that the given area will have demonstrated attainment of 
the applicable PM2.5 NAAQS for at least eight years. With 
respect to second maintenance plans, the 2022 PM2.5 LMP 
Guidance indicates that the LMP submission should address the area's 
PM2.5 air quality trends and historical and projected 
vehicle miles traveled (VMT) to meet the regulatory requirements at 40 
CFR 93.109(e). The LMP would need to include documentation supporting 
the demonstration that it would be unreasonable to expect that such an 
area would experience enough motor vehicle emissions growth for a NAAQS 
violation to occur, per 40 CFR 93.109(e). The 2022 PM2.5 LMP 
Guidance goes on to note that if re-entrained road dust emissions have 
been found to be significant for PM2.5 transportation 
conformity purposes under 40 CFR 93.102(b)(3), then the LMP should 
include an additional motor vehicle emissions analysis.
    As a result of neither the EPA Regional Administrator nor the ADEM 
director having made a finding that re-entrained road dust emissions 
within the Birmingham Area were a significant contributor to the 
PM2.5 nonattainment problem, this LMP and ADEM's first 10-
year maintenance plan did not include emissions of re-entrained road 
dust as significant for transportation conformity analyses under 40 CFR 
93.102(b)(3). Therefore, it was not necessary to perform additional on-
road emissions analysis. The Birmingham Area MPO provided local VMT 
data, and ADEM included these VMT data, which show only a 12 percent 
projected VMT growth from the base year of 2017 to the final year of 
the plan in 2034, in the submittal. Additionally, EPA considered the 
regional emissions analysis results from the most recent transportation 
conformity determination adopted by the Birmingham MPO,\26\ shown in 
Table 5, to include on-road emissions in the year 2024 of 0.57 and 
16.48 tons per day of PM2.5 and NOX, 
respectively.
---------------------------------------------------------------------------

    \26\ A copy of the August 9, 2023, conformity determination is 
included in the docket for more information.

    Table 5--Birmingham MPO 2006 On-Road Emissions in Tons/Day (tpd)
------------------------------------------------------------------------
                                                      On-road  emissions
                    Analysis year                    -------------------
                                                        PM2.5      NOX
------------------------------------------------------------------------
2024................................................      0.57     16.48
2034................................................      0.38      9.14
2044................................................      0.37      8.41
2050................................................      0.38      8.61
------------------------------------------------------------------------

    The PM2.5 on-road emissions are 47 percent below the 
2024 budget of 1.21 tpd. The PM2.5 on-road emissions 
continue to decline steadily from years 2034 to 2050 to 31 percent of 
the budget. The NOX on-road emissions are 34 percent below 
the 2024 budget of 48.41 tpd and continue to decline steadily from 
years 2034 to 2050 to 18 percent of the budget. Because the on-road 
emissions show an overall downward trend for PM2.5 and 
NOX, it would be unreasonable to expect that the Area would 
experience enough motor vehicle emissions growth for a PM2.5 
NAAQS violation to occur as shown by the ADV and CDV calculations 
above. For the preceding reasons, the low projected growth in VMT over 
the 17-year period, and the downward trend in PM2.5 and 
NOX on-road vehicle emissions compared to the budget, the 
mobile source emissions are not expected to adversely impact the Area's 
ability to continue to maintain compliance with the 2006 24-hour 
PM2.5 NAAQS.
    Therefore, the Birmingham Area is eligible for the LMP option, and 
the more detailed mobile source analysis that is found in the 
PM10 LMP Guidance is not required.\27\ EPA proposes to find 
that the long record of monitored PM2.5 concentrations that 
attain the NAAQS, ADEM's air quality statistical analysis and EPA's 
updated analysis, together with the continuation of existing emissions 
control programs, adequately provide for the maintenance of the 2006 
24-hour PM2.5 NAAQS in Birmingham through the second 10-year 
maintenance period and beyond.
---------------------------------------------------------------------------

    \27\ ADEM completed additional motor vehicle emissions analysis 
based on the 2001 PM10 LMP Guidance. This analysis is not 
required for the Birmingham Area under the 2022 PM2.5 LMP 
Guidance, and EPA is not relying on it here. See the February 2, 
2021, SIP revision for more details on this analysis.
---------------------------------------------------------------------------

2. Stability of PM2.5 Levels
    As discussed above, the Birmingham Area has maintained air quality 
well below the 2006 24-hour PM2.5 NAAQS during the first 
maintenance period. Additionally, the DV data shown within Table 2 
illustrate that 24-hour PM2.5 levels have been relatively 
stable over this timeframe, with a modest downward trend. For example, 
the data within Table 2 indicate that the highest year-over-year change 
in complete DVs at any given monitor between 2015-2019 was 2 [mu]g/
m\3\, which represented a 10 percent change. See, e.g., the change at 
the Leeds monitor (AQS 01-073-1010) from 2014-2016 to 2015-2017. 
Furthermore, the overall trend in DVs for the Birmingham Area between 
2015 and 2019 shows a decrease of 13 percent at the highest-reading 
monitor with valid DVs, North Birmingham 01-073-0023, with overall 
decreases in DVs at each individual monitoring site in the Birmingham 
Area. Considering the 2020, 2021, and 2022 DVs, which were finalized 
after ADEM's February 2, 2021, submittal, the trend between 2015-2022 
shows a decrease of 26.1 percent at the North Birmingham monitor, 01-
073-0023. This downward trend in PM2.5 levels, coupled with 
the relatively small, year-over-year variation in PM2.5 DVs, 
makes it reasonable to conclude that the Birmingham Area will not 
exceed the 2006 24-hour PM2.5 NAAQS during the second 10-
year maintenance period.

C. Monitoring Network and Verification of Continued Attainment

    EPA periodically reviews the PM2.5 monitoring network 
that the Jefferson County Department of Health (JCDH) operates and 
maintains in accordance with 40 CFR part 58. This network plan, which 
is submitted annually to EPA, is consistent with the most recent 
ambient air quality monitoring network assessment. The annual network 
plans developed by ADEM and JCDH follow a public notification and 
review process. EPA has reviewed and approved the 2023 Ambient Air 
Monitoring Network Plan for JCDH.28 29
---------------------------------------------------------------------------

    \28\ ADEM does not monitor PM2.5 in the Birmingham 
MSA.
    \29\ The letter approving this network plan, except for the 
SO2 network, is available in the docket for this 
rulemaking.
---------------------------------------------------------------------------

    To verify the attainment status of the area over the maintenance 
period, the maintenance plan should contain provisions for continued 
operation of an appropriate, EPA-approved monitoring network in 
accordance with 40 CFR part 58. As noted above, JCDH's Network Plan for 
Birmingham, covering the PM2.5 network, has been approved by 
EPA in accordance with 40 CFR part 58, and the State has committed to 
continue operating all required PM2.5 monitors in the Area 
in accordance with part 58. EPA therefore proposes to find that the 
monitoring network is adequate to

[[Page 86310]]

verify continued attainment of the 2006 24-hour PM2.5 NAAQS 
in the Birmingham Area.

D. Contingency Plan

    Section 175A(d) of the CAA requires that a maintenance plan include 
contingency provisions. The purpose of such contingency provisions is 
to prevent future violations of the NAAQS or to promptly remedy any 
NAAQS violations that might occur during the maintenance period. The 
State should identify specific triggers which will be used to determine 
when the contingency measures need to be implemented.
    The LMP contains a commitment from Alabama to adopt, within 18 
months of certification of a violating DV \30\ of the 2006 24-hour 
PM2.5 NAAQS in the Birmingham Area, one or more control 
measures as needed to reattain the NAAQS.\31\ If a certified violation 
occurs, Alabama will assess the violation and consider planned local 
and regional emission reductions and consider additional control 
measures as needed to attain the NAAQS.
---------------------------------------------------------------------------

    \30\ A certified air quality design value would be quality 
assured and quality controlled.
    \31\ ADEM also states that in the event that any given year's 
98th percentile 24-hour concentrations is 36 [mu]g/m\3\ or higher at 
any monitor in the Area the State will evaluate existing control 
measures to determine whether any further emission reductions should 
be implemented at that time.
---------------------------------------------------------------------------

    EPA proposes to find that the contingency provisions in Alabama's 
second maintenance plan for the 2006 24-hour PM2.5 NAAQS 
meet the requirements of CAA section 175A(d).\32\
---------------------------------------------------------------------------

    \32\ See the Contingency Plan section of the LMP for further 
information regarding the contingency plan, including measures that 
ADEM will consider for adoption if a certified violation occurs.
---------------------------------------------------------------------------

E. Conclusion

    EPA proposes to approve the Birmingham LMP for the 2006 24-hour 
PM2.5 NAAQS, which includes updates of the various elements 
(including attainment inventory, assurance of adequate monitoring and 
verification of continued attainment, and contingency provisions) of 
the initial EPA-approved maintenance plan for the 2006 24-hour 
PM2.5 NAAQS. EPA also finds that the Birmingham Area 
qualifies for the LMP option and adequately provides for maintenance of 
the 2006 24-hour PM2.5 NAAQS through 2034, i.e., beyond the 
20 years following redesignation of the Area to attainment, and thereby 
satisfies the requirements for such a plan under CAA section 175A(b). 
EPA is therefore proposing to approve Alabama's February 2, 2021, 
submission of the Birmingham Area 2006 24-hour PM2.5 NAAQS 
LMP as a revision to the Alabama SIP.

V. Transportation Conformity

    Transportation conformity is required by section 176(c) of the CAA. 
Conformity to a SIP means that transportation activities will not 
produce new air quality violations, worsen existing violations, or 
delay timely attainment of the NAAQS. See CAA 176(c)(1)(A) and (B). 
EPA's transportation conformity rule at 40 CFR part 93, subpart A, 
requires that transportation plans, programs, and projects conform to 
SIPs and establishes the criteria and procedures for determining 
whether they conform. The conformity rule generally requires a 
demonstration that emissions from the Regional Transportation Plan 
(RTP) and the Transportation Improvement Program (TIP) are consistent 
with the motor vehicle emissions budget (budget) contained in the 
control strategy SIP revision or maintenance plan. See 40 CFR 93.101, 
93.118, and 93.124. A motor vehicle emissions budget is defined as 
``that portion of the total allowable emissions defined in the 
submitted or approved control strategy implementation plan revision or 
maintenance plan for a certain date for the purpose of meeting 
reasonable further progress milestones or demonstrating attainment or 
maintenance of the NAAQS, for any criteria pollutant or its precursors, 
allocated to highway and transit vehicle use and emissions.'' See 40 
CFR 93.101.
    Under the transportation conformity rule, LMP areas may demonstrate 
conformity without a regional emissions analysis. See 40 CFR 93.109(e). 
For LMPs, which do not include budgets, EPA also reviews whether the 
LMP makes the demonstration that it would be unreasonable to expect so 
much motor vehicle emissions growth that the area would violate the 
NAAQS. See 40 CFR 93.109(e). As discussed in the Section IV above, the 
low VMT growth from 2017 to 2034, the downward trend in 
PM2.5 and NOX on-road vehicle emissions 
documented in the Birmingham MPO's recent conformity determination, and 
the emission results from the MPO's conformity determination compared 
to the 2024 budgets collectively demonstrate that it is unreasonable to 
expect so much motor vehicle emissions growth that the area would 
violate the NAAQS.\33\
---------------------------------------------------------------------------

    \33\ On January 25, 2013, EPA approved the 2024 motor vehicle 
emissions budgets associated with the first 10-year maintenance plan 
for the Birmingham Area for the 2006 24-hour PM2.5 NAAQS. 
See 78 FR 5306.
---------------------------------------------------------------------------

    EPA's substantive criteria for determining the adequacy of certain 
SIP submissions, including maintenance plans, are set out in 40 CFR 
93.118(e)(4). The process for determining adequacy is outlined in 40 
CFR 93.118(f). EPA intends to make its determination regarding the 
adequacy of the Birmingham Area LMP for transportation conformity 
purposes in the near future by completing the adequacy process together 
with any final decision on this proposed rulemaking.
    Today's proposal notifies the public that EPA has received this 
LMP, which EPA will review for adequacy, and begins the public comment 
period. EPA invites the public to comment on the adequacy of the LMP as 
well as other aspects of the action EPA is proposing in this notice. 
Comments submitted as part of the adequacy process must be submitted by 
the close of the comment period on this NPRM.
    If EPA approves this LMP or makes an adequacy finding for this LMP, 
after 2024, the motor vehicle emissions in the Birmingham Area may be 
treated as essentially not constraining for the second 10-year 
maintenance period because EPA would have concluded that it is 
unreasonable to expect that the area will experience so much motor 
vehicle emissions growth during this period of time that a violation of 
the PM2.5 NAAQS would result. When determining conformity of 
transportation plans and TIPs after the year 2024, MPOs would not have 
to do a regional emissions analysis. Birmingham has approved budgets 
from the first 10-year maintenance plan for the year 2024, and if a 
transportation conformity determination is needed and 2024 is in the 
timeframe of the determination, the MPO would have to perform a 
regional emissions analysis and compare the results to the 2024 
budgets. All actions for transportation plans and transportation 
improvement programs that would require a transportation conformity 
determination for the Birmingham 2006 24-hour PM2.5 
maintenance area under EPA's transportation conformity rule provisions 
are considered to have already satisfied the regional emissions 
analysis and ``budget test'' requirements in 40 CFR 93.118. See 40 CFR 
93.109(e) and 69 FR 40004 (July 1, 2004).
    However, because LMP areas are still maintenance areas, certain 
aspects of transportation conformity determinations still will be 
required for transportation plans, programs, and projects. As stated in 
40 CFR 93.109(e), ``A conformity determination that meets other 
applicable criteria in Table 1 of

[[Page 86311]]

paragraph (b) of this section is still required.'' Specifically, 
consultation (40 CFR 93.112) is required for all transportation 
conformity determinations. Conformity determinations for RTPs and TIPs 
still will have to demonstrate that they are fiscally constrained (40 
CFR 93.108) and provide for timely implementation of Transportation 
Control Measures from the applicable implementation plan (40 CFR 
93.113). Any conformity determinations made for transportation projects 
must demonstrate that there is a currently conforming transportation 
plan and TIP (40 CFR 93.114) and that the project is from that 
conforming plan and TIP (40 CFR 93.115), meet the hot-spot requirements 
for projects (40 CFR 93.116), and ensure that the project complies with 
any PM control measures in the SIP (40 CFR 93.117).
    Additionally, conformity of transportation plans and TIPs, plan and 
TIP amendments, and transportation projects must be demonstrated in 
accordance with the timing requirements specified in 40 CFR 93.104; for 
RTPs and TIPs, this is no less frequently than every four years.

VI. General Conformity

    The conformity requirement under CAA section 176(c) ensures that 
Federal activities implemented by Federal agencies will not interfere 
with a State's ability to attain and maintain the NAAQS. Under CAA 
176(c)(1), the requirement prohibits Federal agencies from approving, 
permitting, licensing, or funding activities that do not conform to the 
purpose of the applicable SIP for the control and prevention of air 
pollution. See CAA section 176(c)(1)(A). Under CAA section 
176(c)(1)(B), conformity to an implementation plan means that Federal 
activities will not cause or contribute to any new violations of the 
NAAQS, increase the frequency or severity of any existing NAAQS 
violation, or delay timely attainment or any required interim emissions 
reductions or other milestones contained in the applicable SIP.
    The general conformity program implements CAA section 176(c)(4)(A), 
and the criteria and procedures for determining conformity of general 
Federal activities to the applicable SIP are established under 40 CFR 
part 93, subpart B, sections 93.150 through 93.165. General conformity 
requirements apply to Federal activities that (1) would cause emissions 
of relevant criteria or precursor pollutants to originate within 
nonattainment areas or areas that have been redesignated to attainment 
with an approved CAA section 175A maintenance plan (i.e., maintenance 
areas), as given under 40 CFR 93.153(b), and (2) are not Federal 
Highway Administration (FHWA) or Federal Transit Administration (FTA) 
transportation projects as defined in 40 CFR 93.101 under the 
transportation conformity requirements. See 40 CFR 93.153(a).
    The general conformity regulations do not provide special 
flexibility to account for when EPA establishes a LMP for a maintenance 
area. EPA notes that the PM10 LMP Guidance (2001) stated 
that Federal actions subject to the general conformity regulations 
could be considered to satisfy the ``budget test'' because the budgets 
are essentially considered to be unlimited (i.e., unconstrained). 
However, unlike the transportation conformity regulations, the concept 
of unconstrained emissions budgets has no meaning under the general 
conformity regulations. There is no provision in the general conformity 
regulations for a LMP claiming unconstrained emissions budgets and no 
exception to applying the limitations of the de minimis threshold rates 
to an action's emissions that could trigger the requirement for a 
general conformity determination. The concept of an unconstrained 
budget cannot be relied upon by a Federal agency to make a general 
conformity determination. Thus, for general Federal actions proposed 
for maintenance areas with LMPs, such as this proposed rulemaking, the 
criteria and procedures outlined in subpart B shall apply in the same 
way as for any non-LMP maintenance area.

VII. Proposed Action

    Under sections 110(k) and 175A of the CAA and for the reasons set 
forth above, EPA is proposing to approve the Birmingham Area LMP for 
the 2006 24-hour PM2.5 NAAQS, submitted by ADEM on February 
2, 2021, as a revision to the Alabama SIP. EPA is proposing to approve 
the Birmingham Area LMP because it includes an acceptable update of the 
various elements of the 2006 24-hour PM2.5 NAAQS maintenance 
plan approved by EPA for the first 10-year period (including emissions 
inventory, assurance of adequate monitoring and verification of 
continued attainment, and contingency provisions), and retains the 
relevant provisions of the SIP.
    EPA also finds that the Birmingham Area qualifies for the LMP 
option. We propose to approve the LMP because the Birmingham Area LMP 
adequately provides for maintenance of the 2006 24-hour 
PM2.5 NAAQS over the second 10-year maintenance period, 
through 2034, and thereby satisfies the requirements for such a plan 
under CAA section 175A(b).

VIII. Statutory and Executive Order Reviews

    Under the CAA, the Administrator is required to approve a SIP 
submission that complies with the provisions of the CAA and applicable 
Federal regulations. See 42 U.S.C. 7410(k); 40 CFR 52.02(a). Thus, in 
reviewing SIP submissions, EPA's role is to approve State choices, 
provided that they meet the criteria of the CAA. Accordingly, this 
action proposes to approve State law as meeting Federal requirements 
and does not impose additional requirements beyond those imposed by 
State law. For that reason, this proposed action:
     Is not a significant regulatory action subject to review 
by the Office of Management and Budget under Executive Orders 12866 (58 
FR 51735, October 4, 1993) and 14094 (88 FR 21879, April 11, 2023);
     Does not impose an information collection burden under the 
provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.);
     Is certified as not having a significant economic impact 
on a substantial number of small entities under the Regulatory 
Flexibility Act (5 U.S.C. 601 et seq.);
     Does not contain any unfunded mandate or significantly or 
uniquely affect small governments, as described in the Unfunded 
Mandates Reform Act of 1995 (Pub. L. 104-4);
     Does not have federalism implications as specified in 
Executive Order 13132 (64 FR 43255, August 10, 1999);
     Is not subject to Executive Order 13045 (62 FR 19885, 
April 23, 1997) because it approves a State program;
     Is not a significant regulatory action subject to 
Executive Order 13211 (66 FR 28355, May 22, 2001); and
     Is not subject to requirements of section 12(d) of the 
National Technology Transfer and Advancement Act of 1995 (15 U.S.C. 272 
note) because application of those requirements would be inconsistent 
with the CAA.
    In addition, the SIP is not approved to apply on any Indian 
reservation land or in any other area where EPA or an Indian tribe has 
demonstrated that a tribe has jurisdiction. In those areas of Indian 
country, the proposed rule does not have Tribal implications and will 
not impose substantial direct costs on Tribal governments or preempt 
Tribal law as specified by Executive Order 13175 (65 FR 67249, November 
9, 2000).
    Executive Order 12898 (Federal Actions To Address Environmental

[[Page 86312]]

Justice in Minority Populations and Low-Income Populations, 59 FR 7629, 
Feb. 16, 1994) directs Federal agencies to identify and address 
``disproportionately high and adverse human health or environmental 
effects'' of their actions on minority populations and low-income 
populations to the greatest extent practicable and permitted by law. 
EPA defines environmental justice (EJ) as ``the fair treatment and 
meaningful involvement of all people regardless of race, color, 
national origin, or income with respect to the development, 
implementation, and enforcement of environmental laws, regulations, and 
policies.'' EPA further defines the term fair treatment to mean that 
``no group of people should bear a disproportionate burden of 
environmental harms and risks, including those resulting from the 
negative environmental consequences of industrial, governmental, and 
commercial operations or programs and policies.''
    ADEM did not evaluate EJ considerations as part of its SIP 
submittal; the CAA and applicable implementing regulations neither 
prohibit nor require such an evaluation. EPA did not perform an EJ 
analysis and did not consider EJ in this proposed action. Due to the 
nature of the action being proposed here, this proposed action is 
expected to have a neutral to positive impact on the air quality of the 
affected area. Consideration of EJ is not required as part of this 
proposed action, and there is no information in the record inconsistent 
with the stated goal of E.O. 12898 of achieving EJ for people of color, 
low-income populations, and Indigenous peoples.

List of Subjects in 40 CFR Part 52

    Environmental Protection, Air Pollution Control, Incorporation by 
reference, Intergovernmental relations, Nitrogen dioxide, Particulate 
Matter, Reporting and recordkeeping requirements, Sulfur oxides, 
Volatile organic compounds.

    Authority: 42 U.S.C. 7401 et seq.

    Dated: December 7, 2023.
Jeaneanne Gettle,
Acting Regional Administrator, Region 4.
[FR Doc. 2023-27297 Filed 12-12-23; 8:45 am]
BILLING CODE 6560-50-P