Determination of Attainment by the Attainment Date and Clean Data Determination for the 2012 Annual Fine Particulate Standard; Plumas County, California
Key claim: EPA proposes that the Portola nonattainment area in Plumas County, California attained the 2012 annual PM2.5 NAAQS by its December 31, 2025 Serious area deadline, and proposes a clean data determination that would suspend certain Clean Air Act requirements for the area.
Abstract
(Proposed Rule · Environmental Protection Agency) 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. This proposed determination is based on ambient air quality monitoring data from 2023 through 2025. We are also proposing to make a clean data determination (CDD) based on the 2023 through 2025 data. If we finalize this CDD, certain Clean Air Act (CAA) requirements that apply to the Portola nonattainment area will be suspended for so long as the area continues to meet the 2012 annual PM2.5 NAAQS. The area would remain designated nonattainment for the 2012 annual PM2.5 NAAQS, unless and until the State submits, and EPA approves, a redesignation request and maintenance plan for the area. We are taking comments on this proposal and plan to follow with a final action.
Why this matters
Attainment and clean-data determinations directly affect the scope of state and local planning obligations under the Clean Air Act, potentially suspending SIP submissions, contingency measures, and attainment demonstrations for the affected area. For Portola, the practical effect is regulatory relief for state and local agencies contingent on continued monitored compliance with the 2012 annual PM2.5 standard, while public-health exposure remains tied to ongoing air quality rather than the designation itself.