The revision is a separate document to the Arizona Regional Haze State Implementation Plan submitted December 2003. The Revision meets specific commitments outlined in the December 2003 SIP (Enclosures 2 through 7) as well as a correction to the authorizing regional haze statutes. The submittal contains a SIP completeness checklist and seven enclosures.

This document includes an attainment demonstration and formal request to the United States Environmental Agency to redesignate the San Manuel, Arizona area, a nonattainment area for sulfur dioxide (SO2), to attainment for the health-based 24-hour average and annual average SO2 National Ambient Air Quality Standards (NAAQS). It summarizes the progress of the area in attaining the SO2 standard, demonstrates that all Clean Air Act requirements for attainment have been adopted, and includes a maintenance plan to assure continued attainment after redesignation.

In a rule published July 2, 2002, EPA found the Arizona Department of Environmental Quality’s "Plan for Attainment of the 24-Hour PM10 Standard – Maricopa County PM10 Nonattainment Area" (May 1997), inadequate to achieve attainment of the 24-hour National Ambient Air Quality Standards for particulate matter 10 microns or fewer in aerodynamic diameter (PM10) at the Salt River monitoring site. The 1997 ADEQ SIP revision included attainment and Reasonable Further Progress demonstrations for the 24-hour NAAQS at the Salt River air quality monitoring site of the Maricopa County PM10 Serious Nonattainment Area, as well as at three other monitoring sites in the Phoenix area, - the Maryvale, Gilbert, and West Chandler sites. On August 4, 1997, EPA approved ADEQ’s attainment and RFP demonstrations for the Salt River monitoring area, which showed that the 24-hour PM10 NAAQS would reach attainment in the area by May 1998. Due to continuing violations of the 24-hour PM10 NAAQS at the Salt River air quality monitoring site since May 1998, EPA subsequently required Arizona to submit a revision to correct SIP inadequacies. This document consists of Arizona’s revisions to the state implementation plan for the Maricopa County PM10 Serious Nonattainment Area as described by EPA in its Federal Register notice of disapproval.

The Clean Air Act states that an area designated as nonattainment due to a violation of the NAAQS may be redesignated to attainment if the State submits and EPA approves a plan demonstrating that permanent emission controls that resulted in attainment will remain in place. This plan demonstrates that all CAA requirements for attainment and maintenance have been met and summarizes the progress of the area in attaining the PM10 standard. This document includes a formal request to EPA to redesignate the Rillito, Arizona PM10 nonattainment area to attainment for the health-based 24-hour average PM10 NAAQS.

The regional haze rule explicitly recognizes the authority of tribes to implement the provisions of the rule, in accordance with principles of federal Indian law, and as provided by the Clean Air Act and the tribal authority rule. The amount of modification, if any, needed for this report to fulfill tribal needs may vary
considerably from tribe to tribe. The authors have striven to ensure that all references to tribes in the document are consistent with principles of tribal sovereignty and autonomy as reflected in the above framework.

The Arizona State Implementation Plan describes the programs that the State will rely upon to make reasonable progress toward “preventing any future and … remedying any existing impairment of visibility” in the large parks and wilderness areas in Arizona and those in other states that may be affected by pollution generated in Arizona (Class I areas). The federal regional haze rules require states to develop and submit SIPs for improving visibility through the year 2018 that make reasonable progress toward achieving “natural visibility conditions” by the year 2064. This plan is designed to adopt the basic visibility program that addresses impairment of visibility that can be traced to older major industrial sources and implements recommendations adopted by the Grand Canyon Visibility Transport Commission in its 1996 report to EPA.