Clean Data Determination; 1997 8-Hour Ozone Standards; California; Sacramento Metro Area
Key claim: EPA proposes to find that the Sacramento Metro area now meets the 1997 ozone air-quality standard, which would pause certain Clean Air Act requirements for the area as long as it stays in attainment.
Abstract
(Proposed Rule · Environmental Protection Agency) The U.S. Environmental Protection Agency (EPA or “Agency”) is proposing to issue a clean data determination (CDD) for the Sacramento Metro, California nonattainment area to reflect our finding that the area is attaining the 1997 8-hour ozone national ambient air quality standards (NAAQS or “standards”). This finding is based on quality-assured and certified ambient air quality monitoring data from 2023 through 2025. If we finalize this CDD, certain Clean Air Act (CAA) requirements that apply to the Sacramento Metro area will be suspended for so long as the area continues to attain the 1997 8-hour ozone NAAQS. We are taking comments on this proposal and plan to follow with a final action.
Why this matters
Clean data determinations pause a set of Clean Air Act attainment-planning obligations (like attainment demonstrations and contingency measures) as long as the area keeps meeting the standard, reducing near-term SIP workload for California regulators without formally redesignating the area. Because the 1997 ozone NAAQS has been superseded by tighter 2008 and 2015 standards — under which Sacramento remains nonattainment — the practical effect on emitters and permitting is limited.