Determination of Attainment by the Attainment Date and Clean Data Determination for the 2012 Annual Fine Particulate Standard; Plumas County, California

The Environmental Protection Agency (EPA) is proposing to determine that the Portola nonattainment area in Plumas County, California, attained the 2012 annual fine particulate matter (“PM2.5”) national ambient air quality standard (NAAQS or “standard”) by the December 31, 2025 “Serious” area attainment date. We are also proposing to make a clean data determination (CDD) based on our determination that preliminary air quality monitoring data from 2022 indicate the Portola nonattainment area continues to attain the 2012 annual PM2.5 NAAQS. If we finalize this CDD, certain Clean Air Act (CAA) requirements that apply to the Northern Sierra Air Quality Management District (NSAQMD or “District”) will be suspended for so long as the area continues to meet the 2012 annual PM2.5 NAAQS. The area will remain designated as nonattainment for the 2012 annual PM2.5 NAAQS. We are taking comments on this proposal and plan to follow with a final action.