Final rule · 2026-01766

Determination of Attainment by the Attainment Date and Clean Data Determination; California, San Joaquin Valley 1997 Annual PM2.5 Fine Particulate Matter Nonattainment Area

The Environmental Protection Agency (EPA) is finalizing our determination that the San Joaquin Valley, California, fine particulate matter (PM<INF>2.5</INF>) nonattainment area attained the 1997 annual PM<INF>2.5</INF> national ambient air quality standards (NAAQS) by the December 31, 2024 applicable attainment date. This determination is based on ambient air quality monitoring data from 2022 through 2024. We are also making a clean data determination (CDD) based on the 2022 through 2024 data and our evaluation of preliminary air quality monitoring data from 2025.