Air Plan Approval; Arizona; Maricopa County; Reasonably Available Control Technology-Combustion Sources

The Environmental Protection Agency (EPA) is taking final action to approve a revision to the Maricopa County Air Quality Department's (MCAQD or "County") portion of the Arizona State Implementation Plan (SIP). This revision concerns emissions of oxides of nitrogen (NO<INF>X</INF>) and particulate matter (PM) from combustion equipment and internal combustion engines. We are approving local rules that regulate these emission sources under the Clean Air Act (CAA or "Act") and making the determination that the County's control measures implement Reasonably Available Control Technology (RACT) for major sources of NO<INF>X</INF> under the 2008 8-hour ozone National Ambient Air Quality Standard (NAAQS).