Determination of Attainment by the Attainment Date but for International Emissions for the 2015 Ozone National Ambient Air Quality Standards; Phoenix-Mesa Nonattainment Area, Arizona

Document Headings Document headings vary by document type but may contain the following: the agency or agencies that issued and signed a document the number of the CFR title and the number of each part the document amends, proposes to amend, or is directly related to the agency docket number / agency internal file number the RIN which identifies each regulatory action listed in the Unified Agenda of Federal Regulatory and Deregulatory Actions See the Document Drafting Handbook for more details. Environmental Protection Agency 40 CFR Part 52 [EPA-R09-OAR-2025-2833; FRL-13057-01-R9] AGENCY: Environmental Protection Agency (EPA). ACTION: Proposed rule. SUMMARY: The Environmental Protection Agency (EPA or “Agency”) is proposing to determine that the Phoenix-Mesa nonattainment area (“Phoenix-Mesa area”) would have attained the 2015 ozone national ambient air quality standards (NAAQS) by the August 3, 2024 “Moderate” area attainment date, but for emissions emanating from outside the United States. If we finalize this proposed action, the Phoenix-Mesa area would no longer be subject to the Clean Air Act (CAA) requirements pertaining to reclassification upon failure to attain and therefore would remain classified as a Moderate nonattainment area for the 2015 ozone NAAQS. This action, when finalized, will fulfill the EPA's statutory obligation to determine whether the Phoenix-Mesa area attained the NAAQS by the attainment date. DATES: Comments must be received on or before December 19, 2025. ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R09-OAR-2025-2833 at https://www.regulations.gov . For comments submitted at Regulations.gov , follow the online instructions for submitting comments. Once submitted, comments cannot be edited or removed from Regulations.gov . The EPA may publish any comment received to its public docket. Do not submit electronically any information you consider to be Confidential Business Information (CB…