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.

For two and a half decades, the men and women of ADEQ have dedicated themselves to the noble cause of environmental stewardship. They have helped us respect the delicate balance between the natural world and the people who depend on it for sustenance, prosperity and a rewarding quality of life. Most importantly, they have served diligently and passionately to conserve and protect Arizona's natural bounty for generations to come.

On February 2, 2005, Governor Janet Napolitano signed Executive Order 2005-02 establishing the Climate Change Advisory Group. It directed the CCAG, under the coordination of the Arizona Department of Environmental Quality (ADEQ), to:
1) prepare an inventory and forecast of Arizona greenhouse gas (GHG) emissions; and
2) develop a Climate Change Action Plan with recommendations for reducing GHG emissions in Arizona.