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

What it does

The Environmental Protection Agency (EPA or "Agency") is taking final action to determine that the Phoenix-Mesa nonattainment area ("Phoenix-Mesa area") would have attained the 2015 ozone national ambient air quality standards (NAAQS or "standards") by the August 3, 2024 "Moderate" area attainment date, but for emissions emanating from outside the United States. As a consequence of this action, the Phoenix-Mesa area is not subject to the Clean Air Act (CAA) requirements pertaining to reclassification upon failure to attain and remains classified as a Moderate nonattainment area for the 2015 ozone NAAQS. This final action fulfills the EPA's statutory obligation to determine whether the Phoenix-Mesa area attained the NAAQS by the attainment date. As a result of this final action, the State is no longer required to submit attainment and reasonable further progress (RFP) contingency measures for this area.

The Environmental Protection Agency's summary, as published in the Federal Register.

What changed in the regulation

1 part of Title 40 of the Code of Federal Regulations:

40 CFR 52

Wording on eCFR: the day before it took effect and from the day it took effect (first part listed).

Compared with

The Environmental Protection Agency has published 245 final rules in 2026 so far, compared with 263 in all of 2025.

Counted by the Tribune from Federal Register records since Jan. 1, 2025.

What happens next and when

This rule is effective March 23, 2026.

The agency's dates, word for word.

Check it yourself

• The document in the Federal Register
• Docket EPA-R09-OAR-2025-2833 on Regulations.gov
• Title 40 on eCFR

The record as published

Source: the Federal Register (public domain). The document in the Federal Register