Rule2025-19714
Determination of Attainment by the Attainment Date; California; Mariposa County; 2015 8-Hour Ozone National Ambient Air Quality Standards
Primary source
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Published
October 30, 2025
Effective
December 1, 2025
Issuing agencies
Environmental Protection Agency
Abstract
The Environmental Protection Agency (EPA) is taking final action to determine that the Mariposa County nonattainment area in California ("Mariposa area") attained the 2015 ozone national ambient air quality standards (NAAQS or "standard") by its August 3, 2024 attainment date. Our determination of attainment is based on complete, quality-assured, and certified ambient air quality monitoring data for calendar years 2021-2023, excluding data that showed exceedances due to exceptional events that occurred in 2021 and 2022. As a result of this action, Clean Air Act (CAA or "Act") section 172(c)(9) contingency measures for failure to attain the 2015 ozone NAAQS and contingency measures for failure to make reasonable further progress (RFP) are no longer required for this standard in the Mariposa area. This action fulfills the EPA's statutory obligation to determine whether the Mariposa area attained the NAAQS by the attainment date.
Full Text
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<title>Federal Register, Volume 90 Issue 208 (Thursday, October 30, 2025)</title>
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[Federal Register Volume 90, Number 208 (Thursday, October 30, 2025)]
[Rules and Regulations]
[Pages 48820-48822]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2025-19714]
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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 52
[EPA-R09-OAR-2025-0084; FRL-12611-02-R9]
Determination of Attainment by the Attainment Date; California;
Mariposa County; 2015 8-Hour Ozone National Ambient Air Quality
Standards
AGENCY: Environmental Protection Agency (EPA).
ACTION: Final rule.
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SUMMARY: The Environmental Protection Agency (EPA) is taking final
action to determine that the Mariposa County nonattainment area in
California (``Mariposa area'') attained the 2015 ozone national ambient
air quality standards (NAAQS or ``standard'') by its August 3, 2024
attainment date. Our determination of attainment is based on complete,
quality-assured, and certified ambient air quality monitoring data for
calendar years 2021-2023, excluding data that showed exceedances due to
exceptional events that occurred in 2021 and 2022. As a result of this
action, Clean Air Act (CAA or ``Act'') section 172(c)(9) contingency
measures for failure to attain the 2015 ozone NAAQS and contingency
measures for failure to make reasonable further progress (RFP) are no
longer required for this standard in the Mariposa area. This action
fulfills the EPA's statutory obligation to determine whether the
Mariposa area attained the NAAQS by the attainment date.
DATES: This rule is effective on December 1, 2025.
ADDRESSES: The EPA has established a docket for this action under
Docket ID No. EPA-R09-OAR-2025-0084. All documents in the docket are
listed at <a href="https://www.regulations.gov">https://www.regulations.gov</a>. Although listed in the index,
some information is not publicly available, e.g., Confidential Business
Information (CBI) or other information whose disclosure is restricted
by statute. Certain other material, such as copyrighted material, is
not placed on the internet and will be publicly available only in hard
copy form. Publicly available docket materials are available through
<a href="https://www.regulations.gov">https://www.regulations.gov</a>, or please contact the person identified in
the FOR FURTHER INFORMATION CONTACT section. If you need assistance in
a language other than English or if you are a person with disabilities
who needs a reasonable accommodation at no cost to you, please contact
the person identified in the FOR FURTHER INFORMATION CONTACT section.
FOR FURTHER INFORMATION CONTACT: Roxana Sierra-Hern[aacute]ndez, Air
Planning Section, Planning & Analysis Branch, Air & Radiation Division,
EPA Region IX, 75 Hawthorne Street, San Francisco, CA 94105. By phone
at (213) 244-1891, or by email at <a href="/cdn-cgi/l/email-protection#085b616d7a7a69406d7a6669666c6d72265a6770696669486d7869266f677e"><span class="__cf_email__" data-cfemail="04576d617676654c61766a656a60617e2a566b7c656a65446174652a636b72">[email protected]</span></a>.
SUPPLEMENTARY INFORMATION: Throughout this document, ``we,'' ``us,''
and ``our'' refer to the EPA.
Table of Contents
I. Summary of the Proposed Action
II. Public Comments and EPA Responses
III. Final Determination
IV. Statutory and Executive Order Reviews
I. Summary of the Proposed Action
On June 3, 2025,\1\ the EPA proposed to determine that the Mariposa
area, classified as ``Moderate'' for the 2015 ozone NAAQS, attained the
2015 ozone NAAQS by the August 3, 2024 attainment date. The EPA
proposed this determination to fulfill our statutory obligation under
CAA section 181(b)(2) to determine whether the area attained the 2015
ozone NAAQS by its attainment date. Our proposed determination was
based on complete, quality-assured, and certified ambient air quality
monitoring data.
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\1\ 90 FR 23501 (June 3, 2025).
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In our proposed rulemaking, we provided background information on
the 2015 ozone standard and the Mariposa area designation for it. In
section II of our proposed determination, we explained that an area
attains the 2015 ozone NAAQS when its design value (i.e., the 3-year
average of the annual fourth highest daily maximum 8-hour average
ambient air quality ozone concentration) does not exceed 0.070 parts
per million (ppm).
In our proposed rulemaking, we analyzed the ozone monitoring data
submitted to EPA's Air Quality System (AQS) database for calendar years
2021, 2022, and 2023. Ozone exceedances caused by uncontrollable
wildfire emissions in 2021 and 2022 were excluded from our evaluation
of whether the Mariposa area attained the 2015 ozone NAAQS by the
attainment date. A summary of the resulting ozone design values for the
two ozone monitoring sites in the Mariposa area are shown in Table 1.
[[Page 48821]]
Table 1--2015 Ozone NAAQS Monitoring Data Summary for the Mariposa Area \a\
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4th Highest daily maximum 8-hour average value
Monitoring site (ppm) 2021-2023
AQS site ID name ------------------------------------------------ design value
2021 2022 2023 (ppm) \a\
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06-043-0003................. Yosemite NP- 0.077 0.067 0.068 0.070
Turtleback Dome.
06-043-0006................. Jerseydale........ 0.081 0.070 0.060 0.070
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\a\ The data shown exclude exceedances due to exceptional events.
Source: EPA, AQS Design Value (AMP 480), Report Request ID: 2265346, February 24, 2025.
We also proposed to determine that, if this action is finalized,
the CAA section 172(c)(9) requirement for states to provide contingency
measures in the event the area fails to attain the NAAQS or fails to
achieve RFP would no longer apply for the 2015 ozone standard for the
Mariposa area.
II. Public Comments and EPA Responses
The EPA's proposed action provided a 30-day public comment period
that ended on July 3, 2025. During this period, no comments were
received.
III. Final Determination
Pursuant to section 181(b)(2)(A) of the CAA, the EPA is making a
final determination that the Mariposa area attained the 2015 ozone
NAAQS by the attainment date of August 3, 2024. Once effective, this
final action satisfies the EPA's obligation to determine, based on an
area's air quality as of the attainment date, whether the Mariposa area
attained the 2015 ozone standard by its applicable attainment date.
We are also making a final determination that the CAA requirement
for the state implementation plan to provide for attainment and RFP
contingency measures will no longer apply to the Mariposa area for the
2015 ozone NAAQS. The Mariposa area will not be redesignated and will
continue to comply with applicable requirements for a Moderate ozone
nonattainment area.
IV. Statutory and Executive Order Reviews
A. Executive Order 12866: Regulatory Planning and Review and Executive
Order 13563: Improving Regulation and Regulatory Review
This action is not a significant regulatory action and was
therefore not submitted to the Office of Management and Budget (OMB)
for review.
B. Executive Order 14192: Unleashing Prosperity Through Deregulation
Executive Order 14192 does not apply because actions that make
attainment determinations under Clean Air Act section 181(b)(2) are
exempted from review under Executive Order 12866.
C. Paperwork Reduction Act (PRA)
This action does not impose an information collection burden under
the PRA because this action does not impose additional requirements
beyond those imposed by state law.
D. Regulatory Flexibility Act (RFA)
I certify that this action will not have a significant economic
impact on a substantial number of small entities under the RFA. This
action will not impose any requirements on small entities beyond those
imposed by state law.
E. Unfunded Mandates Reform Act (UMRA)
This action does not contain any unfunded mandate as described in
UMRA, 2 U.S.C. 1531-1538, and does not significantly or uniquely affect
small governments. This action does not impose additional requirements
beyond those imposed by state law. Accordingly, no additional costs to
state, local, or Tribal governments, or to the private sector, will
result from this action.
F. Executive Order 13132: Federalism
This action does not have federalism implications. It will not have
substantial direct effects on the states, on the relationship between
the national government and the states, or on the distribution of power
and responsibilities among the various levels of government.
G. Executive Order 13175: Coordination With Indian Tribal Governments
This action does not have tribal implications, as specified in
Executive Order 13175, because the action 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, and will
not impose substantial direct costs on Tribal governments or preempt
Tribal law. Thus, Executive Order 13175 does not apply to this action.
H. Executive Order 13045: Protection of Children From Environmental
Health Risks and Safety Risks
The EPA interprets Executive Order 13045 as applying only to those
regulatory actions that concern environmental health or safety risks
that the EPA has reason to believe may disproportionately affect
children, per the definition of ``covered regulatory action'' in
section 2-202 of the Executive Order. This action is not subject to
Executive Order 13045 because it does not concern an environmental
health risk or safety risk.
I. Executive Order 13211: Actions That Significantly Affect Energy
Supply, Distribution, or Use
This action is not subject to Executive Order 13211, because it is
not a significant regulatory action under Executive Order 12866.
J. National Technology Transfer and Advancement Act (NTTAA)
Section 12(d) of the NTTAA directs the EPA to use voluntary
consensus standards in its regulatory activities unless to do so would
be inconsistent with applicable law or otherwise impractical. The EPA
believes that this action is not subject to the requirements of section
12(d) of the NTTAA because application of those requirements would be
inconsistent with the CAA.
K. Congressional Review Act
This action is subject to the Congressional Review Act, and the EPA
will submit a rule report to each House of the Congress and to the
Comptroller General of the United States. This action is not a ``major
rule'' as defined by 5 U.S.C. 804(2).
L. Petitions for Judicial Review
Under section 307(b)(1) of the Clean Air Act, petitions for
judicial review of this action must be filed in the United States Court
of Appeals for the appropriate circuit by December 29, 2025. Filing a
petition for reconsideration by the Administrator of this final rule
does not affect the finality of this action for the purposes of
judicial review nor does it extend the time
[[Page 48822]]
within which a petition for judicial review may be filed, and shall not
postpone the effectiveness of such rule or action. This action may not
be challenged later in proceedings to enforce its requirements. (See
CAA section 307(b)(2).)
List of Subjects in 40 CFR Part 52
Environmental protection, Air pollution control, Incorporation by
reference, Intergovernmental relations, Nitrogen oxides, Ozone,
Reporting, Recordkeeping requirements, and Volatile organic compounds.
Authority: 42 U.S.C. 7401 et seq.
Dated: October 20, 2025.
Cheree D. Peterson,
Acting Regional Administrator, Region IX.
For the reasons stated in the preamble, the Environmental
Protection Agency amends part 52, chapter I, title 40 of the Code of
Federal Regulations as follows:
PART 52--APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS
0
1. The authority citation for part 52 continues to read as follows:
Authority: 42 U.S.C. 7401 et seq.
Subpart F--California
0
2. Section 52.282 is amended by adding paragraph (q) to read as
follows:
Sec. 52.282 Control strategy and regulations: Ozone.
* * * * *
(q) Determination of attainment by the attainment date. Effective
December 1, 2025. The EPA has determined that the Mariposa County
Moderate nonattainment area in California attained the 2015 8-hour
ozone National Ambient Air Quality Standards (NAAQS) by the applicable
attainment date of August 3, 2024, based upon complete, quality-assured
and certified data for the calendar years 2021-2023.
[FR Doc. 2025-19714 Filed 10-29-25; 8:45 am]
BILLING CODE 6560-50-P
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