US EPA Designates Sacramento Metro Area as Severe-15 Non-Attainment for 8-Hour Ozone NAAQS

On May 5, 2010, the US Environmental Protection Agency (EPA) published a final rule (see 75 FR 24409) that, among other things, officially reclassified the Sacramento Metro (Metro) area with respect to its non-attainment status in relation to the 1997 8-hour ozone national ambient air quality standard (NAAQS). While the area previously had been designated “serious,” it is now “severe-15” as of June 4, 2010. As a result of this reclassification, by June 4, 2011, the Metro portion of the California State Implementation Plan (SIP) must be revised to make it consistent with New Source Review requirements for 8-hour ozone in “severe-15” areas. This revision will cover the Sacramento Metropolitan Air Quality Management District (AQMD), the Placer County Air Pollution Control District, and the Feather River AQMD. EPA deferred setting a deadline for revising the Metro section of the California SIP to meet the provisions of Clean Air Act section 185, which deals with enforcement against “severe” ozone non-attainment. The final rule required no other SIP revisions.

This action by EPA is part of a long-term effort to bring the Metro area into attainment of 8-hour ozone NAAQS “as expeditiously as practicable, but not later than” June 15, 2019. The rule’s more immediate impact is on general conformity applicability thresholds. For projects that involve federal funding or approval, and that are subject to review under either the California Environmental Quality Act (CEQA) or the National Environmental Policy Act (NEPA), the thresholds for both nitrogen oxides and reactive organic gases are lowered from 50 tons per year to 25 tons per year. In addition, the Metro area’s new non-attainment designation will need to be included in the description of existing air quality conditions in environmental documents.