The U.S. EPA is charged with developing air quality standards for the protection of human health and welfare. EPA is also required to periodically evaluate those standards and revise them as needed. In 1997, EPA completed an analysis of the 1-hour ozone standard and adopted a new more stringent 8-hour standard, which better protects the public from longer periods of exposure to ozone. (For more information see the EPA Web site .)

The ADEQ Air Quality Division worked with stakeholders to develop a recommendation for designating areas of the state that do or do not meet the new standard. On July 15, 2003, the Governor sent recommendations to EPA that all areas of the state, except the Phoenix area in eastern Maricopa County, be designated as attainment/unclassifiable for the 8-hour ozone standard. On April 15, 2004, EPA issued final area designations. The Phoenix 8-hour ozone nonattainment area includes much of eastern Maricopa County and Apache Junction in Pinal County.

As part of the process of implementing the new standard, EPA released the first part of the 8-hour ozone implementation rule. The Phase 1 rule outlines the steps areas should take to meet the new 8-hour standard, including the development of a State Implementation Plan (SIP) revision that details the control strategies necessary to ensure attainment. The rule requires that a SIP for the Phoenix nonattainment area be submitted to EPA by 2007 and that the area meet the new standard by 2009.

The time line below highlights some of the significant past and future events in the 8-hour ozone standard implementation process. Information on Arizona's 8-hour ozone area recommendations, EPA's response and final designations, the implementation rule, as well as meetings and workshops hosted by ADEQ are also provided below. If you have questions or comments, please send them to Bruce Friedl.

Final 8-hour Ozone Area Designation

• Map of Phoenix Nonattainment Area
• EPA's Final 8-hour Ozone Designations and Phase 1 Implementation Rule

Technical Analysis In Support of Arizona's 8-hour Ozone Area Designation Recommendations

• Director's Letter to EPA
• Arizona Air Quality Designations, Boundary Recommendations for the 8-Hour Ozone National Air Quality Standard (Report)
• Appendix 1: EPA's March 28, 2000 Boundary Guidance Memo
• Appendix 2a: Arizona Monitoring Sites Map
• Appendix 2b: Key to Arizona Monitoring Sites Map
• Appendix 3: Annual Fourth Highest 8-Hour Ozone Concentrations
• Appendix 4: Three-Year Average of the Annual Fourth Highest 8-Hour Ozone Concentration
• Appendix 5: Phoenix-Mesa Metropolitan Statistical Area Map
• Appendix 6a: Presentation from June 17, 2003 Stakeholder Meeting
• Appendix 6b: June 17, 2003 Presentation Map Summaries
• Appendix 6c: Technical Analysis for Optional Nonattainment Area Boundaries
• Appendix 7: EPA's Jan. 19, 2001 and July 2, 2003 Letters
• Appendix 8a: Modeling and Emissions Inventory Presentation from May 21, 2003 Stakeholder Meeting
• Appendix 8b: Modeling and Emissions Inventory Report
• Appendix 9: Summaries of WRAP 1996 and MAG's 1999 Emissions Inventories
• Appendix 10a: Socioeconomic Presentation from May 21, 2003 Stakeholder Meeting
• Appendix 10b: May 21, 2003 Socioeconomic Presentation Map Summaries
• Appendix 11: EPA's November 14, 2002 Memo Regarding the 8-hour Designations Schedule
• Appendix 12: MAG Regional Freeway Bottleneck Study
  
  
• EPA's response to Arizona's 8-hour Ozone Area Designation Recommendations

Additional Information

• Timeline for Implementation of the 8-Hour Ozone Standard
• 8-hour Ozone Public Meetings and Workshops
• Map of Ozone Monitoring Sites in Arizona
• Information on Ozone Monitoring Sites and Air Quality Data Contained in ADEQ's 2003 Air Quality Report
• Phoenix Area Ozone Nonattainment Area: the 1-hour standard