Proposed Rule2025-05369
Air Plan Approval; California; State Implementation Plan Revision for Chico, Modesto, and Stockton Carbon Monoxide Maintenance Areas
Primary source
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Published
March 31, 2025
Issuing agencies
Environmental Protection Agency
Abstract
The Environmental Protection Agency (EPA) is proposing to approve a revision to the California state implementation plan (SIP) that removes carbon monoxide (CO) contingency measures and monitoring requirements from the maintenance plan for three CO maintenance areas: Chico Urbanized Area, Modesto Urbanized Area, and Stockton Urbanized Area. We are proposing to approve the revision under the Clean Air Act (CAA or "Act"). We are taking comments on this proposal and plan to follow with a final action.
Full Text
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<title>Federal Register, Volume 90 Issue 60 (Monday, March 31, 2025)</title>
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[Federal Register Volume 90, Number 60 (Monday, March 31, 2025)]
[Proposed Rules]
[Pages 14224-14227]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2025-05369]
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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 52
[EPA-R09-OAR-2024-0473; FRL-12323-01-R9]
Air Plan Approval; California; State Implementation Plan Revision
for Chico, Modesto, and Stockton Carbon Monoxide Maintenance Areas
AGENCY: Environmental Protection Agency (EPA).
ACTION: Proposed rule.
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SUMMARY: The Environmental Protection Agency (EPA) is proposing to
approve a revision to the California state implementation plan (SIP)
that removes carbon monoxide (CO) contingency measures and monitoring
requirements from the maintenance plan for three CO maintenance areas:
Chico Urbanized Area, Modesto Urbanized Area, and Stockton Urbanized
Area. We are proposing to approve the revision under the Clean Air Act
(CAA or ``Act''). We are taking comments on this proposal and plan to
follow with a final action.
DATES: Comments must be received on or before April 30, 2025.
ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R09-
OAR-2024-0473 at <a href="https://www.regulations.gov">https://www.regulations.gov</a>. For comments submitted at
<a href="http://Regulations.gov">Regulations.gov</a>, follow the online instructions for submitting
comments. Once submitted, comments cannot be edited or removed from
<a href="http://Regulations.gov">Regulations.gov</a>. The EPA may publish any comment received to its public
docket. Do not submit electronically any information you consider to be
Confidential Business Information (CBI) or other information whose
disclosure is restricted by statute. Multimedia submissions (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. The EPA will generally not
consider comments or comment contents located outside of the primary
submission (i.e., on the web, cloud, or other file sharing system). For
additional submission methods, please contact the person identified in
the FOR FURTHER INFORMATION CONTACT section. For the full EPA public
comment policy, information about CBI or multimedia submissions, and
general guidance on making effective comments, please visit <a href="https://www.epa.gov/dockets/commenting-epa-dockets">https://www.epa.gov/dockets/commenting-epa-dockets</a>. If you need assistance in a
language other than English or if you are a person with a disability
who needs a reasonable
[[Page 14225]]
accommodation at no cost to you, please contact the person identified
in the FOR FURTHER INFORMATION CONTACT section.
FOR FURTHER INFORMATION CONTACT: Julia Leo, EPA Region IX, 75 Hawthorne
St., San Francisco, CA 94105; phone: (213) 244-1862; email:
<a href="/cdn-cgi/l/email-protection#aec2cbc180c4dbc2c7cfeecbdecf80c9c1d8"><span class="__cf_email__" data-cfemail="533f363c7d39263f3a32133623327d343c25">[email protected]</span></a>.
SUPPLEMENTARY INFORMATION: Throughout this document, ``we,'' ``us,''
and ``our'' refer to the EPA.
Table of Contents
I. Background
II. Requirements of CAA Section 110(l)
III. The State's Submittal and Evaluation for Compliance With SIP
Revision Procedural Requirements
A. The State's Submittal
B. Evaluation for Compliance With SIP Revision Procedural
Requirements
IV. The EPA's Evaluation and Action
A. How is the EPA evaluating the SIP revision?
B. Does the SIP revision meet the evaluation criteria?
C. Proposed Action and Public Comment
V. Statutory and Executive Order Reviews
I. Background
The CAA requires the EPA to set national ambient air quality
standards (NAAQS or ``standards'') for carbon monoxide (CO) as one of
six ``criteria'' air pollutants. In 1971, the EPA established primary
and secondary NAAQS for CO at 9 parts per million (ppm), averaged over
an 8-hour period, and at 35 ppm, averaged over a 1-hour period.\1\
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\1\ 36 FR 8186 (April 30, 1971).
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In 1991, the EPA designated 11 areas in California as nonattainment
for the 9 ppm CO standard: Bakersfield Metropolitan Area, Chico
Urbanized Area, Fresno Urbanized Area, Lake Tahoe North Shore Area,
Lake Tahoe South Shore Area, Los Angeles-South Coast Air Basin Area,
Modesto Urbanized Area, Sacramento Area, San Diego Area, San Francisco-
Oakland-San Jose Area, and Stockton Urbanized Area.\2\
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\2\ 56 FR 56694, 56723-56726 (November 6, 1991).
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In 1996, the California Air Resources Board (CARB) submitted a
redesignation request and maintenance plan (``1996 CO Maintenance
Plan'') \3\ demonstrating continued maintenance of the CO NAAQS in ten
of these areas,\4\ including the Chico Urbanized Area, the Modesto
Urbanized Area, and the Stockton Urbanized Area, through 2010. The EPA
approved the 1996 CO Maintenance Plan as a revision to the California
SIP and redesignated the ten areas to attainment effective June 1,
1998.\5\ In 2004, CARB submitted the ``2004 Revision to the California
State Implementation Plan for Carbon Monoxide, Updated Maintenance Plan
for Ten Federal Planning Areas'' (``2004 CO Second Maintenance Plan'')
\6\ that provided a ten-year update to the 1996 CO Maintenance Plan and
demonstrated that the areas would maintain the CO NAAQS through 2018.
On November 30, 2005, the EPA approved the 2004 CO Second Maintenance
Plan as a revision to the California SIP.\7\ The Chico Urbanized Area,
Modesto Urbanized Area, and Stockton Urbanized Area have completed
their 20-year maintenance periods (from 1998 to 2018) as required under
CAA section 175A.
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\3\ CARB, ``Final Carbon Monoxide Redesignation Request and
Maintenance Plan for Ten Federal Planning Areas (``1996 CO
Maintenance Plan'') (April 26, 1996).
\4\ The 2004 CO Second Maintenance Plan did not include Los
Angeles. The EPA redesignated Los Angeles-South Coast Air Basin to
attainment for CO in 2007. 72 FR 26718 (May 11, 2007).
\5\ 63 FR 15305 (March 31, 1998).
\6\ CARB, ``2004 Revision to the California State Implementation
Plan for Carbon Monoxide,'' adopted July 22, 2004.
\7\ 70 FR 71776 (November 30, 2005).
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II. Requirements of CAA Section 110(l)
CAA section 110(l) provides that ``[t]he Administrator shall not
approve a revision of a plan if the revision would interfere with any
applicable requirement concerning attainment and reasonable further
progress (as defined in [CAA section 171]) or any other applicable
requirement of [the CAA].'' \8\ CAA section 110(l) applies to the
approval of all revisions to SIPs under the CAA and to all areas,
whether attainment, nonattainment, unclassifiable, or maintenance for
one or more of the NAAQS. Before the EPA can conclude that the SIP
revision is allowed under CAA section 110(l), the EPA must first
conclude that the plan revision meets CAA requirements.
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\8\ 42 U.S.C. 7410(l).
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The EPA interprets CAA section 110(l) as applying to all NAAQS that
are in effect, including those for which SIP submissions have not been
made; therefore, the EPA considers the impact of the SIP revision on
emissions and/or ambient concentrations of any pollutant. Additionally,
in certain circumstances, a state may demonstrate non-interference with
CAA applicable requirements by substituting equivalent emissions
reductions to compensate for any change to a SIP to ensure actual
emissions to the air are not increased and thus preserve status quo air
quality.\9\
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\9\ See also Hall v. EPA, 273 F.3d 1146, nn. 11-12 (9th Cir.
2001) (reasoning that, if there is no relaxation of air quality
regulations, a revision to a SIP would not interfere with reasonable
further progress or attainment in areas attaining the NAAQS).
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III. The State's Submittal and Evaluation for Compliance With SIP
Revision Procedural Requirements
A. The State's Submittal
On April 4, 2024, CARB submitted a SIP revision titled ``2023
Revision to the California State Implementation Plan for Carbon
Monoxide,'' \10\ and on January 15, 2025, CARB submitted a
clarification by email \11\ (collectively, the ``2023 CO SIP Revision''
or ``submittal''). The submittal proposes to remove CO contingency
measures and monitoring requirements for the Chico, Modesto, and
Stockton maintenance areas from the 2004 CO Second Maintenance Plan.
CARB proposes updating the 2004 CO Second Maintenance Plan to remove
the contingency measures section on page 11 and monitoring requirements
for the three areas outlined in section II.A.2 on page 6.\12\ To
discontinue CO monitoring, CARB must demonstrate that a contingency
plan is no longer needed and remove associated contingency measures
(that would be triggered by a monitored CO violation) and monitoring
requirements from the SIP. CARB submitted the 2023 CO SIP Revision to
demonstrate that CO monitoring is no longer needed for a contingency
plan in these areas. The proposed revision follows a CO monitor
discontinuation request for these locations submitted by CARB in
September 2022.\13\
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\10\ CARB, ``2023 Revision to the California State
Implementation Plan for Carbon Monoxide,'' February 9, 2024.
\11\ Email dated January 15, 2025, from Ayla Moretti, CARB, to
Jin Xu, CARB, and Karina O'Connor, EPA, Subject: ``RE: discuss a few
questions re: CO maintenance plan SIP revision?''
\12\ Id. and 2023 CO SIP Revision, 14.
\13\ See letter dated September 9, 2022, from Kathleen Gill,
Chief, Air Quality Surveillance Branch, Monitoring and Laboratory
Division, CARB, to Gwen Yoshimura, EPA, Region 9, requesting
discontinuation of CO monitors in four CARB locations. We will act
on the monitoring discontinuation request in a later rulemaking.
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B. Evaluation for Compliance With SIP Revision Procedural Requirements
Under CAA sections 110(a) and 110(l), SIPs and SIP revisions must
be adopted by the state, and the state must provide for reasonable
public notice and hearing prior to adoption. Pursuant to 40 CFR 51.102,
states must provide at least 30-days' notice of any public hearing to
be held on a proposed SIP revision. States must provide the opportunity
to submit written comments and allow the public the opportunity to
request a public hearing within that period.
CARB made the 2023 CO SIP Revision available for a 30-day public
review from February 9, 2024, to March 11, 2024, and no comments were
received. CARB also provided notice, within the 30-day comment period,
to allow the public the opportunity to request a public hearing to be
held on May 23, 2024. The public comment period closed on March 11,
2024, and no request for a public hearing was received. CARB
subsequently adopted the 2023 CO SIP Revision as a revision to the SIP
on April 4, 2024, through Executive Order S-24-006. CARB then submitted
the 2023 CO SIP Revision to the EPA on April 4, 2024, as an attachment
to a transmittal letter dated April 4, 2024 (submitted electronically
on April 5, 2024). Copies of these documents can be found in the docket
for this proposed rule.
Based on the materials provided in the April 4, 2024 SIP
submission, we propose to find that CARB has met the procedural
requirements for adoption and submission of SIPs and SIP revisions
under CAA sections 110(a) and 110(l), and 40 CFR 51.102.
On October 5, 2024, the 2023 CO SIP Revision was deemed by
operation of law to meet the completeness criteria in 40 CFR part 51
appendix V, which must be met before formal EPA review.
IV. The EPA's Evaluation and Action
A. How is the EPA evaluating the SIP revision?
Rules in the SIP must be enforceable (see CAA section 110(a)(2)),
must not interfere with applicable requirements concerning attainment
and reasonable further progress or other CAA requirements (see CAA
section 110(l)), and must not modify certain SIP control requirements
in nonattainment areas without ensuring equivalent or greater emissions
reductions (see CAA section 193). The EPA evaluated the SIP revision to
determine whether the proposed removal of contingency measures and
monitors from the 2004 CO Second Maintenance Plan would interfere with
attainment or maintenance of the NAAQS or conflict with other CAA
requirements.
A SIP revision meeting 110(l) requirements is needed before the EPA
can approve a monitoring discontinuation request under 40 CFR
58.14(c)(1), and completion of the 20-year maintenance period is
necessary before removing monitoring or contingency provisions that
were approved as part of an area's maintenance plan.\14\
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\14\ CAA section 175A(d) and memorandum dated September 4, 1992,
from John Calcagni, Director, Air Quality Management Division, EPA
Office of Air Quality Planning and Standards, Subject: ``Procedures
for Processing Requests to Redesignate Areas to Attainment''
(``Calcagni Memo'').
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B. Does the SIP revision meet the evaluation criteria?
The 2023 CO SIP Revision includes ambient monitoring data to show
that, as of 2022, the three areas' monitored CO levels were 81 percent
to 86 percent below the federal 8-hour CO standard of 9 ppm (table 1 of
this document). The design value for CO is the highest of the second
highest eight-hour concentrations observed at any site in the area over
eight consecutive quarters.\15\ The 2023 design values, also shown in
table 1, were 81 percent to 87 percent below the 8-hour CO NAAQS.\16\
Preliminary data available in the EPA's Air Quality System (AQS) for
2024 (January through March) indicate that the CO maintenance areas
continue to show concentrations below the 1971 8-hour CO NAAQS.\17\
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\15\ Memorandum dated June 18, 1990, from William G. Laxton,
Director, Technical Support Division, EPA, Subject: ``Ozone and
Carbon Monoxide Design Value Calculations.''
\16\ The data used to confirm attainment are the 8-hour CO NAAQS
design values. Id. See also 63 FR 15305, 15306.
\17\ EPA, AQS Raw Data Report (AMP350), Report Request ID:
2229172, October 2, 2024.
Table 1--2022 and 2023 Design Values and Percent Below Federal 8-Hour Standard of 9 ppm
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Percent below Percent below
2022 Design value Federal 8-hour CO 2023 Design value Federal 8-hour CO
CO maintenance area Monitoring site (ppm) (2021-2022 standard (as of (ppm) (2022-2023 standard (as of
data years) the 2022 design data years) the 2023 design
value) value)
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Chico..................................... Chico--East Avenue (AQS ID: 1.3 86 1.2 87
06-007-0008).
Modesto................................... Modesto--14th Street (AQS 1.4 84 1.4 84
ID: 06-099-0005).
Stockton.................................. Stockton--University Park 1.7 81 1.7 81
(AQS ID: 06-077-1003).
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Source: Carbon Monoxide Design Values, 2023, Table 6a. Monitor Trends 8 hr., AQS Data Retrieval, May 7, 2024.
The submittal also includes an explanation of two violations of the
8-hour CO NAAQS in 2018 in the Chico maintenance area. Appendix A of
the submittal provides evidence to support that two 2018 violations of
the maximum 8-hour CO concentration in the Chico maintenance area were
due to wildfire smoke from the November 2018 Camp Fire.
The submittal provides evidence that statewide California CO
emissions declined by 59 percent between 2000 and 2023, mostly driven
by the 82 percent reduction in on-road motor vehicle CO emissions. CO
emissions from stationary and areawide sources declined by 34 percent
and 22 percent, respectively, during the same period. The submittal
includes data to show that CO emissions in the three maintenance areas
decreased between 57 percent and 64 percent between 2000 and 2023. CARB
projects that CO emissions in the maintenance areas will further
decrease by 18 percent to 37 percent between 2023 and 2050 (see table 2
of this document). The projections for 2023 and onward are
significantly lower than the CO emissions in 2004, when the 2004 CO
Second Maintenance Plan revision was
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adopted. CARB attributes this to the benefits of tighter emissions
standards for new engines, fuel requirements, and turnover of the
vehicle fleet to lower-emitting models.
Table 2--Total Winter CO Emissions in Each Maintenance Area
[Winter seasonal emissions in tons per day]
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CO maintenance area Area included in inventory 2000 2010 2023 2030 2050
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Chico..................................... Butte County................ 132 82 57 51 47
Modesto................................... Stanislaus County........... 160 85 58 45 37
Stockton.................................. San Joaquin County.......... 230 125 84 66 57
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Source: 2023 CO SIP Revision, Table 4.
Based on the information in the submittal, we propose to find that
the SIP revision is consistent with CAA 110(l) requirements. CARB's
submittal demonstrates that the removal of contingency measures and
monitoring requirements for the Chico, Modesto, and Stockton urbanized
areas will not interfere with maintenance of the CO standard or other
CAA requirements related to this standard. These areas each continued
to maintain the CO NAAQS throughout their respective 20-year CO
maintenance periods in accordance with their approved maintenance plans
during this time. Additionally, for CO (unlike for lead, where re-
entrainment is an ongoing concern), removal of contingency measures
that require monitoring in the proposed areas would not interfere with
maintenance or other applicable requirements because the area has
monitored below the NAAQS for more than 20 years, and other relevant
control measures remain in place.
Ambient levels of CO in the three maintenance areas where monitors
are proposed for removal have been well below the level of the NAAQS
throughout the maintenance period,\18\ and CARB's analysis of future CO
emissions in these areas demonstrates continued compliance with the CO
NAAQS (see tables 1 and 2 in this document). CO emissions in these
areas dropped significantly from 2000 through 2023, and State measures,
such as CARB's adopted mobile source control strategy, will also
continue to generate further CO emissions reductions, supporting CARB's
demonstration that forecasted emissions will provide for continued
attainment through 2050. Therefore, the EPA also proposes to find that
the submitted revision demonstrates that ambient monitoring in these
three federal CO planning areas is no longer needed.
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\18\ 2023 CO SIP Revision, 5, table 2.
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C. Proposed Action and Public Comment
As authorized in section 110(k)(3) of the Act, and for the reasons
set forth in this document, the EPA proposes to fully approve the 2023
CO SIP Revision submitted by CARB electronically on April 5, 2024,
because it fulfills all relevant requirements. We will accept comments
from the public on this proposal until April 30, 2025.
V. Statutory and Executive Order Reviews
Under the Clean Air Act, the Administrator is required to approve a
SIP submission that complies with the provisions of the Act and
applicable federal regulations. 42 U.S.C. 7410(k); 40 CFR 52.02(a).
Thus, in reviewing SIP submissions, the EPA's role is to approve State
choices, provided that they meet the criteria of the Clean Air Act.
Accordingly, this proposed action merely 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:
<bullet> Is not a significant regulatory action subject to review
by the Office of Management and Budget under Executive Order 12866 (58
FR 51735, October 4, 1993);
<bullet> Does not impose an information collection burden under the
provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.);
<bullet> 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.);
<bullet> 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);
<bullet> Does not have federalism implications as specified in
Executive Order 13132 (64 FR 43255, August 10, 1999);
<bullet> Is not subject to Executive Order 13045 (62 FR 19885,
April 23, 1997) because it proposes to approve a state program;
<bullet> Is not a significant regulatory action subject to
Executive Order 13211 (66 FR 28355, May 22, 2001); and
<bullet> 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 Clean Air Act.
In addition, the SIP is not approved to apply on any Indian
reservation land or in any other area where the EPA or an Indian Tribe
has demonstrated that a Tribe has jurisdiction. In those areas of
Indian country, the 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).
List of Subjects in 40 CFR Part 52
Environmental protection, Air pollution control, Carbon monoxide,
Incorporation by reference, Intergovernmental relations, Reporting and
recordkeeping requirements.
Dated: March 10, 2025.
Cheree D. Peterson,
Acting Regional Administrator, Region IX.
[FR Doc. 2025-05369 Filed 3-28-25; 8:45 am]
BILLING CODE 6560-50-P
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