Air Quality State Implementation Plans; Approvals and Promulgations: California; Mariposa County; 2015 8-Hour Ozone National Ambient Air Quality Standards; Determination of[...]

Determination of Attainment by the Attainment Date; California; Mariposa County; 2015 8-Hour Ozone National Ambient Air Quality Standards

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.

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.

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 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).)

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

Subpart F-California

⁽¹⁾  90 FR 23501 (June 3, 2025).