Final rule · 2025-18636

Finding of Failure To Attain the 1997 8-Hour Ozone Standards; California; San Joaquin Valley

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.