Clean Air Plans; 2008 8-Hour Ozone Nonattainment Area Requirements; Determination of Attainment by the Attainment Date; Imperial County, California

The Environmental Protection Agency (EPA) is approving two state implementation plan (SIP) revisions submitted by the State of California to meet Clean Air Act (CAA or "Act") requirements for the 2008 ozone national ambient air quality standards (NAAQS) in the Imperial County nonattainment area, as follows. The EPA is approving the "Imperial County 2017 State Implementation Plan for the 2008 8- Hour Ozone Standard" ("Imperial Ozone Plan" or "Plan") and the portions of the "2018 Updates to the California State Implementation Plan" ("2018 SIP Update") that address the requirement for a reasonable further progress (RFP) demonstration for Imperial County for the 2008 ozone standards. In addition, the EPA is determining, based on the "Imperial County Clean Air Act Section 179B(b) Retrospective Analysis for the 75 ppb 8-hour Ozone Standard" ("Imperial Ozone Retrospective Demonstration"), that the Imperial County nonattainment area would have attained the 2008 ozone NAAQS by the "Moderate" area attainment date of July 20, 2018, but for emissions emanating from Mexico, and therefore is not subject to the CAA requirements pertaining to reclassification upon failure to attain. As a result of these final actions, the Imperial County nonattainment area will remain classified as a Moderate nonattainment area for the 2008 ozone NAAQS.