Proposed rule · 2026-06441

Finding of Failure To Attain the 2006 24-Hour PM2.5 Standards; California; San Joaquin Valley; Error Correction

In response to a court decision, the Environmental Protection Agency (EPA) is proposing to correct our July 22, 2020 final action erroneously granting a Clean Air Act (CAA or "Act") section 188(e) attainment date extension for the 2006 24-hour fine particulate matter (PM<INF>2.5</INF>) national ambient air quality standards (NAAQS or "standards") in the San Joaquin Valley from December 31, 2019, to December 31, 2024, and is now proposing to deny California's extension request. The EPA is also proposing to determine that the San Joaquin Valley nonattainment area failed to attain the 2006 24-hour PM<INF>2.5</INF> NAAQS by the December 31, 2019 unextended attainment date. This proposed determination is based upon monitored air quality data from 2017 through 2019. If the EPA finalizes this determination as proposed, the State of California will be required to submit a revision to the California state implementation plan (SIP) that, among other elements, provides for expeditious attainment of the 2006 24-hour PM<INF>2.5</INF> NAAQS and for a five percent annual reduction in emissions of direct PM<INF>2.5</INF> or a PM<INF>2.5</INF> plan precursor pollutant.