Air Plan Approval: Arizona: Infrastructure Requirements for the 2012 Fine Particulate Matter National Ambient Air Quality Standard

<RULE> ENVIRONMENTAL PROTECTION AGENCY <CFR>40 CFR Parts 52 and 81</CFR> <DEPDOC>[EPA-R09-OAR-2023-0539; FRL-11747-02-R9]</DEPDOC> <SUBJECT>Air Plan Approval: Arizona: Infrastructure Requirements for the 2012 Fine Particulate Matter National Ambient Air Quality Standard</SUBJECT> <HD SOURCE="HED">AGENCY:</HD> Environmental Protection Agency (EPA). <HD SOURCE="HED">ACTION:</HD> Final rule. <SUM> <HD SOURCE="HED">SUMMARY:</HD> The Environmental Protection Agency (EPA) is taking final action to approve portions of the state implementation plan (SIP) revisions submitted by the State of Arizona pursuant to the Clean Air Act (CAA) for the implementation, maintenance, and enforcement of the 2012 fine particulate matter (PM <E T="52">2.5</E> ) national ambient air quality standards (NAAQS or “standards”) as proposed, except for certain requirements related to prevention of significant deterioration (PSD), which EPA will defer action on until a later date. In addition, the EPA is approving regulatory provisions into the Arizona SIP and is amending regulatory text to include La Paz County as part of Mohave-Yuma Intrastate air quality control region (AQCR). </SUM> <EFFDATE> <HD SOURCE="HED">DATES:</HD> This rule is effective January 20, 2026. </EFFDATE> <HD SOURCE="HED">ADDRESSES:</HD> The EPA has established a docket for this action under Docket ID No. EPA-R09-OAR-2023-0539. All documents in the docket are listed on the <E T="03">https://www.regulations.gov</E> website. Although listed in the index, some information is not publicly available, <E T="03">e.g.,</E> 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 <E T="03">https://www.regulations.gov,</E> or please contact the person identified in the <E T="02">FOR FURTHER INFORMATION CONTACT</E> section for additional availability information. If you need assistance in a language other than English or if you are a person with a disability who needs a reasonable accommodation at no cost to you, please contact the person identified in the <E T="02">FOR FURTHER INFORMATION CONTACT</E> section. <FURINF> <HD SOURCE="HED">FOR FURTHER INFORMATION CONTACT:</HD> Michael Dorantes, Geographic Strategies and Modeling Section (AIR-2-2), EPA Region IX, 75 Hawthorne Street, San Francisco, CA, telephone number: (415) 972-3934, email address: <E T="03">dorantes.michael@epa.gov.</E> </FURINF> <SUPLINF> <HD SOURCE="HED">SUPPLEMENTARY INFORMATION:</HD> Throughout this document, “we,” “us,” and “our” refer to the EPA. <HD SOURCE="HD1">Table of Contents</HD> <EXTRACT> <FP SOURCE="FP-2">I. Background</FP> <FP SOURCE="FP1-2">A. Statutory Requirements</FP> <FP SOURCE="FP1-2">B. State Submittals</FP> <FP SOURCE="FP1-2">C. Summary of EPA's Proposal and Incorporation of Rules Into Arizona's State Implementation Plan</FP> <FP SOURCE="FP1-2"> D. Revising Air Quality Control Regions and Evalutating Emergency Episode Planning Requirements for PM <E T="52">2.5</E> in Arizona </FP> <FP SOURCE="FP-2">II. Public Comments and EPA Responses</FP> <FP SOURCE="FP-2">III. Final Action</FP> <FP SOURCE="FP1-2">A. Approvals</FP> <FP SOURCE="FP1-2">B. Deferred Action</FP> <FP SOURCE="FP1-2">C. Incorporation of Rules Into Arizona's State Implementation Plan</FP> <FP SOURCE="FP1-2"> D. Revising Air Quality Control Regions and Evaluating Emergency Episode Planning Requirements for PM <E T="52">2.5</E> in Arizona </FP> <FP SOURCE="FP-2">IV. Incorporation by Reference</FP> <FP SOURCE="FP-2">V. Statutory and Executive Order Reviews</FP> </EXTRACT> <HD SOURCE="HD1">I. Background</HD> <HD SOURCE="HD2">A. Statutory Requirements</HD> Section 110(a)(1) of the CAA requires each state to submit to the EPA, within three years after the promulgation of a primary or secondary NAAQS or any revision thereof, a SIP revision that provides for the implementation, maintenance, and enforcement of such NAAQS. Section 110(a)(2) of the CAA contains the infrastructure SIP requirements that generally relate to the information, authorities, compliance assurances, procedural requirements, and control measures that constitute the “infrastructure” of a state's air quality management program. These infrastructure SIP requirements (or “elements”) required by section 110(a)(2) are as follows: • Section 110(a)(2)(A): Emission limits and other control measures. • Section 110(a)(2)(B): Ambient air quality monitoring/data system. • Section 110(a)(2)(C): Program for enforcement of control measures and regulation of new and modified stationary sources. • Section 110(a)(2)(D)(i): Interstate pollution transport. • Section 110(a)(2)(D)(ii): Interstate and international pollution abatement. • Section 110(a)(2)(E): Adequate resources and authority, conflict of interest, and oversight of local and regional government agencies. • Section 110(a)(2)(F): Stationary source monitoring and reporting. • Section 110(a)(2)(G): Emergency episodes. • Section 110(a)(2)(H): SIP revisions. • Section 110(a)(2)(J): Consultation with government officials, public notification, PSD, and visibility protection. • Section 110(a)(2)(K): Air quality modeling and submittal of modeling data. • Section 110(a)(2)(L): Permitting fees. • Section 110(a)(2)(M): Consultation/participation by affected local entities. There are certain infrastructure SIP requirements under section 110(a)(2) that are not addressed in this final action. First, two elements identified in section 110(a)(2) are not governed by the three-year submittal deadline of section 110(a)(1). These two elements are: (i) section 110(a)(2)(C), to the extent that it refers to permit programs required under part D (nonattainment new source review (NSR)), and (ii) section 110(a)(2)(I), pertaining to the nonattainment planning requirements of part D. As a result, this action does not address the nonattainment NSR requirements of section 110(a)(2)(C) or the entirety of section 110(a)(2)(I). Additionally, this action does not address the requirements of section 110(a)(2)(D)(i)(I) pertaining to contributions to nonattainment or interference with maintenance in other States, referred to as “prongs 1 and 2” and 110(a)(2)(D)(i)(II) pertaining to interference with visibility protection in other States, referred to as “prong 4.” The EPA has proposed action on Arizona's SIP revision with respect to prongs 1 and 2 in a separate rulemaking, <SU>1</SU> <FTREF/> and has finalized action on prong 4 in a separate rulemaking. <SU>2</SU> <FTREF/> Finally, there are several requirements, for which we originally proposed partial approval and partial disapproval, <SU>3</SU> <FTREF/> that we will now be deferring action on. These include the requirements of 110(a)(2)(C) as they relate to major source preconstruction PSD permitting, but also extend to the portions of 110(a)(2)(D)(i), 110(a)(2)(D)(ii), and 110(a)(2)(J) that reference PSD requirements and rely on our analysis of PSD permitting in Element C. We will be addressing the PSD requirements of 110(a)(2)(C), 110(a)(2)(D)(i), 110(a)(2)(D)(ii), and 110(a)(2)(J) in a separate, future rulemaking. <FTNT> <SU>1</SU>  90 FR 48502 (October 23, 2025). </FTNT> <FTNT> <SU>2</SU>  The EPA finalized its partial approval and partial disapproval the Arizona Regional Haze Plan for the Second Implementation Period as well as its disapproval of prong 4 requirements on May 31, 2024 (89 FR 102744). On July 15, 2025, EPA granted petitions for reconsideration of our final action on the Arizona Regional Haze Plan. </FTNT> <FTNT> <SU>3</SU>  89 FR 50245, 50249-50250 (June 13, 2024). </FTNT> <HD SOURCE="HD2">B. State Submittals</HD> The Arizona Department of Environmental Quality (ADEQ) submitted two SIP revisions to address the infrastructure SIP requirements in CAA sections 110(a)(1) and 110(a)(2) for the 2012 PM <E T="52">2.5</E> NAAQS. On December 11, 2015, ADEQ submitted the “Arizona State Implementation Plan Revision for the 2012 Fine Particulate Matter (PM <E T="52">2.5</E> ) National Ambient Air Quality Standard” (“2015 PM <E T="52">2.5</E> I-SIP submittal”). <SU>4</SU> <FTREF/> On February 10, 2022, ADEQ submitted the “State Implementation Plan Revision: Clean Air Act Section 110(a)(2) for the 2012 Fine Particulate & 2015 Ozone NAAQS” (“2022 I-SIP supplement”). <SU>5</SU> <FTREF/> These submittals collectively address Arizona's obligation to satisfy infrastructure SIP requirements for the 2012 PM <E T="52">2.5</E> NAAQS. We refer to them herein as “Arizona's 2012 PM <E T="52">2.5</E> I-SIP submittals.” <FTNT> <SU>4</SU>  Letter dated December 11, 2015, from Eric Massey, Director, Air Quality Division, ADEQ, to Jared Blumenfeld, Regional Administrator, EPA Region IX, Subject: “Arizona Infrastructure State Implementation Plan for the 2012 PM <E T="52">2.5</E> National Ambient Air Quality Standards.” </FTNT> <FTNT> <SU>5</SU>  Letter dated February 10, 2022, from Daniel Czecholinski, Director, Air Quality Division, ADEQ, to Martha Guzman, Regional Administrator, EPA Region IX, Subject: “Submittal of the Arizona State Implementation Plan Revision under Clean Air Act Sections 110(a)(2) for the 2012 Fine Particulate and the 2015 Ozone NAAQS.” </FTNT> We are taking final action on these submittals with respect to the 2012 PM <E T="52">2.5</E> NAAQS except for those portions of the 2012 PM <E T="52">2.5</E> I-SIP submittals addressing prongs 1, 2, and 4 of the interstate transport requirements under CAA section 110(a)(2)(D)(i). Additionally, we are deferring action on the requirements under CAA section 110(a)(2)(C), 110(a)(2)(D)(i), 110(a)(2)(D)(ii), and 1 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Preview showing 10k of 37k characters. Full document text is stored and available for version comparison. ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━