Data / Federal rules / 2025-18636
Finding of Failure To Attain the 1997 8-Hour Ozone Standards; California; San Joaquin Valley
The Environmental Protection Agency published this final rule in the Federal Register on September 25, 2025. It took effect on October 27, 2025.
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What the agency says
The Environmental Protection Agency (EPA) has determined that the San Joaquin Valley, California area failed to attain the 1997 8- hour ozone national ambient air quality standard (NAAQS) by its June 15, 2024 "Extreme" area attainment date. This determination is based on quality-assured and certified ambient air quality monitoring data from 2021 through 2023. As a result of this determination, the State of California is required to implement nonattainment contingency measures and the stationary source fee program required under Clean Air Act (CAA) section 185.
Key facts
- Document number
- 2025-18636
- Type
- Final rule
- Action
- Final determination
- Agency
- Environmental Protection Agency
- Published
- September 25, 2025
- Takes effect
- October 27, 2025
- Dates
- This determination is effective on October 27, 2025.
- Docket
- EPA-R09-OAR-2024-0587; FRL-12483-02-R9
- Code of Federal Regulations
- 40 CFR 52
- Topics
- Air pollution control; Environmental protection; Incorporation by reference; Intergovernmental relations; Nitrogen oxides; Ozone; Reporting and recordkeeping requirements; Volatile organic compounds
- Pages
- 3
Other documents from the Environmental Protection Agency
Everything from the Environmental Protection Agency · Rules on air pollution control · Rules on environmental protection · Rules on incorporation by reference · Published in September 2025
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.