In October 2009, the U.S. Environmental Protection Agency (EPA) asked the Governor to submit a recommendation designating areas of Pinal County as being either attainment, nonattainment or unclassifiable (inadequate data to make a determination) for the inhalable particulate matter (PM₁₀) and fine particulate matter (PM_2.5) National Ambient Air Quality Standards (NAAQS). EPA's request is based on PM₁₀ and PM_2.5 concentrations measured in the western portion of the County that are in violation of the NAAQS.

ADEQ's recommendation to the Governor followed careful consideration of the 1987 24-hour PM₁₀ and 1997 Annual PM_2.5 standards, requirements for designation of nonattainment areas, and options available for implementing the standards. For more information on particulate matter and the PM₁₀ and PM_2.5 standards go to EPA's Particulate Matter Web page

The following information for the Pinal County PM₁₀ and PM_2.5 Boundary Designations are available for review:

• EPA Letters to Governor Janice K. Brewer - Area Designations for the 1997 Annual PM_2.5 Standard and 1987 24-hour PM₁₀ Standard (October 8, 2009) (October 14, 2009)
• Federal Register Notice: Air Quality Designations for the 2006 24-Hour Fine Particle (PM_2.5) National Ambient Air Quality Standards; Final Rule (40 CFR Part 81; see pp. 58697-8)
• EPA Nonattainment Area Designation Guidance to Regional Administrators Regarding the Revised 24-Hour Fine Particle National Ambient Air Quality Standard (June 8, 2007)
• Letter from Governor Brewer to EPA on PM₁₀ and PM_2.5 Nonattainment Area Boundary Recommendations (March 23, 2010)
• Recommended Pinal County PM₁₀ Nonattainment Area Boundary (PM₁₀ Recommendation Map and Technical Support Document
• ADEQ Analysis of PM_2.5 Exceedances in Pinal County
• Pinal County Air Quality Control District Source Apportionment Study
• Comments Received on Particulate Matter Area Designation Recommendations
• Summary of Comments Received and ADEQ's Responses
• EPA Letter to Governor Brewer on Proposed 24-Hour Average PM_2.5 Nonattainment Area Boundary (May 10, 2010)
• EPA Letter to ADEQ Director Benjamin Grumbles Extending the Deadline for Designation of the Pinal County PM_2.5 Nonattainment Area (June 2, 2010)
• EPA Technical Support Document for the Proposed Pinal County PM_2.5 Nonattainment Area Boundary (Technical Support Document)
• Governor Janice K. Brewer Letter to EPA Proposing Pinal County PM2.5 Area Boundary Designation
• ADEQ Director Grumbles Letter to EPA Transmitting Technical Support Document to EPA Region 9 and ADEQ Technical Support Document Boundary Recommendation for the Pinal County 24-Hour Standard PM2.5 Nonattainment Area
• September 2006 revisions to Particulate Matter NAAQS (PM₁₀ and PM_2.5) EPA Fact Sheet
• EPA Brochure: Particle Pollution and Your Health

For more information, please contact:

Corky Martinkovic, (602) 771-2372