# Pennsylvania.
**AGENCY:**
Environmental Protection Agency (EPA).
**ACTION:**
Final rule.
**SUMMARY:**
The Environmental Protection Agency (EPA) is approving the Commonwealth of Pennsylvania's request to redesignate the Allegheny County, Pennsylvania nonattainment area (Allegheny County Area) to attainment for the 2012 annual fine particulate matter (PM <sub>2.5</sub> ) national ambient air quality standards (NAAQS or standard). The redesignation request was submitted by the Commonwealth of Pennsylvania Department of Environmental Protection (PADEP or Pennsylvania) on behalf of the Allegheny County Health Department (ACHD). This action is being taken under the CAA.
**DATES:**
This final rule is effective on May 18, 2026.
**ADDRESSES:**
The EPA has established a docket for this action under Docket ID Number EPA-R03-OAR-2025-1777. All documents in the docket are listed on the *www.regulations.gov* website. 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 *www.regulations.gov,* or please contact the person identified in the *For Further Information Contact* section for additional availability information.
**FOR FURTHER INFORMATION CONTACT:**
Ian Neiswinter, Planning & Implementation Branch (3AD30), Air & Radiation Division, U.S. Environmental Protection Agency, Region III, 1600 John F. Kennedy Boulevard, Philadelphia, Pennsylvania 19103. The telephone number is (215) 814-2011. Mr. Neiswinter can also be reached via electronic mail at *[email protected].*
**SUPPLEMENTARY INFORMATION:**
Throughout this document, wherever “we,” “us,” or “our” are used, it is intended to refer to the EPA.
**I. Background**
Fine particulate pollution can be emitted directly from a source (primary PM <sub>2.5</sub> ) or formed secondarily through chemical reactions in the atmosphere involving precursor pollutants emitted from a variety of sources. The main precursors of secondary PM <sub>2.5</sub> are sulfur dioxide (SO <sub>2</sub> ), nitrogen oxides (NO <sub>X</sub> ), ammonia (NH <sub>3</sub> ), and volatile organic compounds (VOCs). [^1] Sulfates are a type of secondary particulate formed from SO <sub>2</sub> emissions from power plants and industrial facilities. Nitrates, another common type of secondary particulate, are formed from combustion emissions of NO <sub>X</sub> from power plants, mobile sources, and other combustion sources.
[^1]*See* 81 FR 58010 (August 24, 2016).
On January 15, 2013 (78 FR 3086), the EPA promulgated a revised primary annual PM <sub>2.5</sub> NAAQS to provide increased protection of public health from fine particle pollution. In that action, the EPA strengthened the primary annual PM <sub>2.5</sub> standard from 15.0 micrograms per cubic meter (µg/m <sup>3</sup> ) to 12.0 µg/m <sup>3</sup> , which is attained when the 3-year average of the annual arithmetic mean does not exceed 12.0 µg/m <sup>3</sup> . On January 15, 2015 (80 FR 2206), the EPA published air quality designations for the 2012 annual PM <sub>2.5</sub> NAAQS. In that action, the EPA designated all municipalities in Allegheny County, Pennsylvania as one moderate nonattainment area (Allegheny County Area) for the 2012 annual PM <sub>2.5</sub> NAAQS. *See* 40 CFR 81.339. On September 4, 2025 PADEP, on behalf of ACHD, formally submitted a redesignation request for the Allegheny County Area for the 2012 annual PM <sub>2.5</sub> NAAQS.
Section 107(d)(3)(E) of the CAA allows redesignation of an area to attainment of the NAAQS provided that: (1) the Administrator (EPA) determines that the area has attained the applicable NAAQS; (2) the Administrator has fully approved the applicable implementation plan for the area under section 110(k) of the CAA; (3) the Administrator determines that the improvement in air quality is due to permanent and enforceable reductions in emissions resulting from implementation of the applicable SIP, applicable Federal air pollutant control regulations, and other permanent and enforceable emission reductions; (4) the Administrator has fully approved a maintenance plan for the area as meeting the requirements of section 175A of the CAA; and (5) the State containing the area has met all requirements applicable to the area for purposes of redesignation under section 110 and part D of the CAA.
On November 20, 2025 (90 FR 52319), the EPA published a notice of proposed rulemaking (NPRM) for the Commonwealth of Pennsylvania. In the NPRM, the EPA proposed approval of Pennsylvania's September 4, 2025 request to redesignate the Allegheny County Area to attainment for the 2012 annual PM <sub>2.5</sub> NAAQS. Notably, the EPA approved the relevant maintenance plan in a previous action. *See* 90 FR 34770 (July 25, 2025).
**II. Summary of the EPA Analysis**
The EPA reviewed Pennsylvania's redesignation request and found that the requirements for redesignating the Allegheny County Area to attainment for the 2012 annual PM <sub>2.5</sub> NAAQS have been satisfied pursuant to CAA section 107(d)(3)(E). The EPA is thus approving Pennsylvania's request to change the designation of the Allegheny County Area from nonattainment to attainment for the 2012 annual PM <sub>2.5</sub> NAAQS. The details of Pennsylvania's request and the rationale for the EPA's now final action are explained in the NPRM and will not be restated here.
**III. The EPA's Response to Comments Received**
The EPA's November 20, 2025 NPRM (90 FR 52319) opened a 30-day public comment period, which closed on December 22, 2025. The EPA received comments from two commenters. Those comments and the EPA's responses are discussed below. All of the comments received and any submitted attachments are included in the docket for this rule, available at, *www.regulation.gov* , Docket ID Number EPA-R03-OAR-2025-1777.
On December 22, 2025, Midwest Ozone Group (MOG) submitted comments on the NPRM. In summary, MOG agrees with and supports the EPA's proposed action to redesignate the Allegheny County Area to attainment for the 2012 annual PM <sub>2.5</sub> NAAQS. The EPA acknowledges and appreciates MOG's comments.
On November 20, 2025, the Citizens Rulemaking Alliance (CRA) submitted comments on the NPRM. The following is a summary of CRA's comments and the EPA's responses.
*Comment:* The commenter claimed that the EPA did not comply with multiple statutory requirements, Executive Order 12866, and transportation conformity requirements. The commenter attributes each of these alleged procedural and statutory deficiencies to a claim that this action proposes to approve a CAA section 175A maintenance plan, including motor vehicle emissions budgets (“budgets”) for transportation conformity under CAA section 176(c) and 40 CFR part 93. First, the commenter claims that the EPA did not comply with the Regulatory Flexibility Act/Small Business Regulatory Enforcement Fairness Act (RFA/SBREFA) because the approval of budgets will impact transportation conformity determinations within the state, and as a result, impact small entities. The commenter states that the action either lacks a 605(b) certification or provides only a conclusory statement. Second, the commenter claims that the EPA did not comply with the Unfunded Mandates Reform Act (UMRA) because the approval of a maintenance plan and its contingency measures will make them federally enforceable, and budgets immediately impact transportation planning. As a result, local jurisdictions can incur planning, modeling, and project costs. The commenter claims that the EPA did not quantify these expenditures or explain why they are below UMRA thresholds. Third, the commenter claims that the EPA did not comply with the Paperwork Reduction Act (PRA) because the approved maintenance plan may contain recordkeeping, monitoring, and reporting provisions administered by ACHD and local transportation agencies. The commenter states that the EPA should clearly state if there are any information collection requirements and include the relevant Office of Management and Budget (OMB) control number. Fourth, the commenter claims that the EPA did not comply with Executive Order 12866, and that the notice should include a clear statement as to whether the action is a significant regulatory action, and if not, the basis for that determination. The commenter states that given the implication of budgets on a large metropolitan area, the EPA should provide a short explanation regarding the significance demonstration. Fifth, the commenter claims the EPA did not comply with the transportation conformity budgets adequacy process under 40 CFR part 93 because the document and docket do not appear to include the required adequacy materials or make them available for public comment. Lastly, the commenter states that if this was a direct final rule, the EPA must withdraw the direct final rule and proceed via notice-and-comment if adverse comment is received.
*Response:* The EPA disagrees with the commenter with respect to each issue raised. This action does not approve a maintenance plan under CAA section 175A or budgets under CAA section 176(c) and 40 CFR part 93. Therefore, the commenter's claims that the EPA did not comply with the RFA/SBREFA, UMRA, PRA, Executive Order 12866, and the transportation conformity budget adequacy process with respect to approval of a maintenance plan or budgets, or due to provisions in the maintenance plan and budgets, are beyond the scope of this action, which is limited to redesignation of the nonattainment area to attainment. The cause of noncompliance cited by the commenter for each statute, Executive Order 12866, and transportation conformity is not part of this rulemaking. The EPA previously approved, in a separate rulemaking, Pennsylvania's maintenance plan for the Allegheny County Area for the 2012 annual PM <sub>2.5</sub> NAAQS as a revision to the Pennsylvania SIP because it met the requirements of CAA section 175A. [^2] The maintenance plan included 2017, 2026, and 2035 PM <sub>2.5</sub> and NO <sub>X</sub> budgets for the Allegheny County Area for the 2012 annual PM <sub>2.5</sub> NAAQS. The EPA's analysis of the budgets for the Allegheny County Area can be found in the EPA's budget technical support document (TSD) prepared for that rule, available online at *www.regulations.gov,* Docket ID: EPA-R03-OAR-2024-0586. The maintenance plan became federally enforceable on August 25, 2025, the effective date of the EPA's approval. ACHD must implement the provisions of the maintenance plan, including budgets and contingency provisions, irrespective of this action, which merely approves Pennsylvania's request to redesignate the Allegheny County Area from nonattainment to attainment for the 2012 annual PM <sub>2.5</sub> NAAQS. Of note, the EPA did not receive any comments on that action specific to the RFA, UMRA, PRA, Executive Order 12866, or the EPA's adequacy determination and approval of budgets.
[^2]*See* 90 FR 34770 (July 25, 2025).
Additionally, this action was not a direct final rule. The EPA published a proposed rule on November 20, 2025 (90 FR 52319) which opened a 30-day public comment period that closed on December 22, 2025. In this action, we are finalizing the November 20, 2025 proposed rule. The generic statement from the commenter that if this was a direct final rule, the EPA must withdraw the direct final and proceed via notice-and-comment if adverse comment is received, along with the mistaken claim that this action approves a maintenance plan and budgets, highlights that the commenter seems to have compiled a series of generic comments that were not specific to this action.
**IV. Final Action**
The EPA is approving Pennsylvania's request to redesignate the Allegheny County Area to attainment for the 2012 annual PM <sub>2.5</sub> NAAQS. The EPA has evaluated Pennsylvania's redesignation request and determined that ambient air monitoring data demonstrates that the Allegheny County Area has attained the NAAQS and the Area has met the redesignation criteria set forth in section 107(d)(3)(E) of the CAA. The effect of this final action is to change the designation status of the Allegheny County Area from nonattainment to attainment for the 2012 annual PM <sub>2.5</sub> NAAQS.
**IV. Statutory and Executive Order Reviews**
Under the CAA, the redesignation of an area to attainment is an action that affects the status of a geographical area and does not impose any additional regulatory requirements on sources beyond those required by state law. A redesignation to attainment does not in and of itself impose any new requirements, but rather results in the application of requirements contained in the CAA for areas that have been redesignated to attainment. For that reason, this action:
• 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);
• Is not subject to Executive Order 14192 (90 FR 9065, February 6, 2025) because this action is exempt from review under Executive Order 12866:
• 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 an economically significant regulatory action based on health or safety risks subject to Executive Order 13045 (62 FR 19885, April 23, 1997);
• 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 Clean Air Act.
In addition, this 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. 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).
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).
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 June 15, 2026. 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 section 307(b)(2).)
**List of Subjects in 40 CFR Part 81**
Environmental protection, Air pollution control, Carbon monoxide, Intergovernmental relations, Lead, Nitrogen dioxide, Ozone, Particulate matter, Reporting and recordkeeping requirements, Sulfur oxides, Volatile organic compounds.
Amy Van-Blarcom Lackey,
Regional Administrator, Region III.
For the reasons stated in the preamble, the EPA amends 40 CFR part 81 as follows:
**PART 81—DESIGNATION OF AREAS FOR AIR QUALITY PLANNING PURPOSES**
**40 CFR Part 81**
1. The authority citation for part 81 continues to read as follows:
**Authority:**
42 U.S.C. 7401 *et seq.*
**40 CFR Part 81**
2. In § 81.339, amend the table “Pennsylvania—2012 Annual PM <sub>2.5</sub> NAAQS” by revising the entry for “Allegheny County, PA” to read as follows:
§ 81.339
| Designated area | Designation | Date | Type | Classification | Date | Type |
| --- | --- | --- | --- | --- | --- | --- |
| Allegheny County, PA: | | | | | | |
| Allegheny County | 5/18/2026 | Attainment | | | | |
| | | | | | | |
| * * * * * * * | | | | | | |