Data / Federal rules / 2026-11169

Revisions of the Nonattainment Designation for the 2008 and 2015 Ozone Standards and Clean Data Determinations for the 2008 and 2015 Ozone Standards: Cecil County, MD and New Castle County, DE

The Environmental Protection Agency published this final rule in the Federal Register on June 4, 2026. It took effect on July 6, 2026.

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What the agency says

The Environmental Protection Agency (EPA) is approving two separate requests from Maryland and Delaware to revise the designation for the Philadelphia-Wilmington-Atlantic City, PA-NJ-MD-DE nonattainment area for the 2008 primary and secondary ozone national ambient air quality standards (NAAQS) and the 2015 primary and secondary ozone NAAQS. Due to the concurrent requests from Maryland and Delaware, the EPA is revising the Philadelphia-Wilmington-Atlantic City, PA-NJ-MD-DE nonattainment area boundary into three distinct nonattainment areas that together cover the identical geographic area of the existing area. The EPA is also issuing clean data determinations (CDDs) for the revised Maryland and Delaware nonattainment areas for both the 2008 and 2015 ozone NAAQS. The EPA is taking this action pursuant to Clean Air Act (CAA) sections 107, 110, 172, and 182.

Key facts

Document number: 2026-11169
Type: Final rule
Action: Final rule
Agency: Environmental Protection Agency
Published: June 4, 2026
Takes effect: July 6, 2026
Dates: This final rule is effective on July 6, 2026.
Docket: EPA-R03-OAR-2025-1872; FRL-12994-02-R3
Code of Federal Regulations: 40 CFR 52; 40 CFR 81
Topics: Air pollution control; Environmental protection; Incorporation by reference; Intergovernmental relations; Nitrogen dioxide; Ozone; Reporting and recordkeeping requirements; Volatile organic compounds
Pages: 8

The document on federalregister.gov PDF

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Everything from the Environmental Protection Agency · Rules on air pollution control · Rules on environmental protection · Rules on incorporation by reference · Published in June 2026

Read from the Federal Register API, last updated 2026-10-23. The document on federalregister.gov is the official record; dates and dockets can change through later corrections. Free to reuse with credit to SpecStream under CC BY 4.0.