Approval and Promulgation of Implementation Plans; Designation of Areas for Air Quality Planning Purposes; State of California; PM-10; Determination of Attainment for the Coso Junction Nonattainment Area; Determination Regarding Applicability of Certain Clean Air Act Requirements

EPA is finalizing its determination that the Coso Junction nonattainment area (CJNA) has attained the 24-hour National Ambient Air Quality Standard (NAAQS) for particulate matter with an aerodynamic diameter less than or equal to a nominal 10 micrometers (PM-10). This determination is based upon quality-assured and certified air quality monitoring data for the PM-10 NAAQS from 2006-2008. In addition, reported data in EPA's Air Quality System (AQS) show that the CJNA continued to attain the PM-10 NAAQS through 2009 and preliminary data available to date for 2010 show that the CJNA continues to attain. Also, EPA is finalizing its determination that, because the CJNA has attained the PM-10 NAAQS, the State's obligation to make submissions to meet certain Clean Air Act (CAA or the Act) requirements is not applicable for as long as the CJNA continues to attain the PM-10 NAAQS.