Partial Approval and Disapproval of Air Quality Implementation Plans; Arizona; Infrastructure Requirements for Ozone and Fine Particulate Matter

EPA is approving in part and disapproving in part State Implementation Plan (SIP) revisions submitted by the state of Arizona pursuant to the requirements of the Clean Air Act (CAA) for the 1997 8- hour ozone national ambient air quality standards (NAAQS) and the 1997 and 2006 NAAQS for fine particulate matter (PM<INF>2.5</INF>). The Clean Air Act requires that each State adopt and submit a SIP for the implementation, maintenance, and enforcement of each NAAQS promulgated by the EPA. Arizona has met most of the applicable requirements. Where EPA is disapproving, in part, Arizona's SIP revisions, several of the deficiencies have already been addressed by a federal implementation plan (FIP). The remaining deficiencies are subject to a two-year deadline for EPA to promulgate a FIP, unless EPA approves an adequate SIP revision prior to that time. EPA remains committed to working with Arizona to develop such a SIP revision.