Findings of Failure To Attain; State of Arizona, Phoenix Nonattainment Area; State of California, Owens Valley Nonattainment Area; Particulate Matter of 10 Microns or Less

EPA is finalizing its findings that the Phoenix Planning Area (Phoenix nonattainment area) and the Owens Valley Planning Area (Owens Valley nonattainment area) did not attain the 24-hour National Ambient Air Quality Standard (NAAQS) for particulate matter of 10 microns or less (PM-10) by the deadline mandated in the Clean Air Act (CAA or the Act), December 31, 2006. These findings are based on monitored air quality data for the PM-10 NAAQS from 2004 through September 2006. Several Indian tribes have reservations located within the boundaries of the Phoenix and Owens Valley nonattainment areas. EPA implements CAA provisions for determining whether such areas have attained the NAAQS by the applicable attainment deadline. After affording the affected tribal leaders the opportunity to consult with EPA on its proposed actions, the Agency is also finding that the tribal areas have failed to attain the 24-hour PM-10 NAAQS. As a result of these failures to attain findings, Arizona and California must submit by December 31, 2007, plan provisions that provide for attainment of the 24-hour PM-10 NAAQS and that achieve 5 percent annual reductions in PM-10 or PM-10 precursor emissions as required by CAA section 189(d).