Phoenix Area, Maricopa and Pinal Counties

On February 07, 1978, Governor Wesley Bolin designated the Maricopa Association of Governments (MAG) as the lead air quality planning organization for the Maricopa County portion of the Phoenix Metropolitan area. See Arizona Revised Statutes (A.R.S.) §49-406. MAG, working with its member governments and agencies in consultation with ADEQ, ADOT, and the Pinal County Air Quality Control District, is responsible for developing Arizona SIP requirements in the Phoenix Nonattainment Area for particulate matter. Plans produced by MAG are implemented and enforced by the Maricopa County Air Quality Department (MCAQD), federal, state and local government agencies with jurisdiction in Arizona.

PM₁₀ Nonattainment Area

The primary sources of coarse particulate pollution in the Phoenix area are fugitive and windblown dust from unpaved roads, vacant lots, trackout onto paved roads, disturbed areas on mining sites, construction sites, and agricultural fields and areas where off-highway vehicles are in use.

The nonattainment area within Maricopa County and Township 1 N, Range 8 East in Pinal County was reclassified to a serious PM₁₀ nonattainment area on June 10, 1996. On July 09, 1999, MAG submitted to ADEQ for adoption and submittal to the U.S. EPA the MAG 1999 Serious Area Particulate Plan for PM₁₀, addressing both the 24-hour and annual standards with Best Available Control Measures (BACM). The U.S. EPA revoked the annual PM₁₀ standard in 2006. Commitments for the metropolitan areas within the nonattainment area are listed in the Appendices of the SIP (Volumes I through IV) and are available upon request. Check the Table of Contents for specific listings.

A revised plan was submitted in February 2000. The Plan added the Most Stringent Measures (MSM) in the nation and included an extension request for attainment no later than December 31, 2006. On January 14, 2002, the U.S. EPA announced the approval of the Serious Area Plan and also granted a five year extension of the attainment date for both the 24-hour and annual PM₁₀ standards from December 31, 2001 to December 31, 2006. Both decisions were published in the Federal Register on July 25, 2002 (67 FR 48718).

Additionally, on July 02, 2002, the U.S. EPA found that more work was needed to attain the 24-hour standard in the area of the Salt River monitoring site. For more information on the "Salt River Study Area" see Salt River PM₁₀ State Implementation Plan Revision.

5% Annual Reasonable Further Progress PM₁₀ SIP Revision for Maricopa County and Township 1 North, Range 8 East Pinal County Nonattainment Area

The Proposed 2012 5% Plan for PM₁₀ for the Pinal County Portion of the State Implementation Plan (SIP) for the Maricopa County Nonattainment Area public comment period began March 23, 2012 and ended April 24, 2012, and a public hearing was held on April 24, 2012.

• Public Notice
• Proposed Plan

Despite the MSMs and BACMs adopted and implemented earlier, the area failed to attain the National Ambient Air Quality Standards (NAAQS) by the extended deadline of December 31, 2006. This failure triggered a special requirement under Section 189(d) of the Clean Air Act that SIP revisions provided for annual reductions of PM₁₀ or PM₁₀ precursors of not less than 5 percent of the most recent emissions inventory, until the NAAQS is attained, be submitted to the U.S. EPA by December 31, 2007.

The MAG 2007 Five Percent Plan for PM₁₀ focusing on winter stagnation exceedances was prepared by MAG, approved and submitted by ADEQ to the U.S. EPA by the December 31, 2007. The SIP revision contains rule revisions in Maricopa County (Rules 310, 310.01, and 316) and Pinal County (Chapter Four, Pinal County Code) to further reduce PM₁₀ emissions; five additional Agricultural Best Management Practices (BMPs); doubled the number of BMPs required per category, and expanded the area to which the BMPs apply. Although exceedances of the standard were recorded during elevated winds in 2009, no violations of the 24-hour standard were recorded in 2010. Numerous exceedances resulting from high wind events were recorded in 2011. ADEQ and WESTAR continue to work with U.S. EPA on implementation of the Exceptional Events Rule to flag exceedances data on days when control measures for anthropogenic emissions are overwhelmed by natural and exceptional events and exclude them from regulatory determinations.

Senate Bill 1552 (2007) addressed the authority to revise the rules and BMPs while also adding requirements for both Maricopa County and one township in Pinal County. Cities and towns in the nonattainment area committed to develop and enforce local ordinances to address PM10 contributions from vacant lots, unpaved roads and shoulders, off-highway vehicles, and leaf blowers. Senate Bill 1225 (2009) added members to the Governor's Agricultural Best Management Practices Committee, required rule revisions to address specified animal operations, and revised the "regulated area" definition. For operations deemed not in compliance with the agricultural general permit, Senate Bill 1193 (2010) shortened the timeframe that a regulated activity has to submit a BMP plan once it receives a compliance order.

The U.S. EPA proposed a limited disapproval of the Five Percent Plan on September 09, 2010 (75 FR 54806). After ADEQ withdrew the plan on January 25, 2011, U.S. EPA made a Finding of Failure to Submit the Five Percent Plan on February 14, 2011 (76 FR 8300), triggering an 18-month sanctions clock and a two-year Federal Implementation Plan clock. The Replacement Five Percent Plan will include a revised emission inventory including a revised Motor Vehicle Emissions Budget (MVEB) and a revised control strategy focusing on high wind days. House Bill 2208 (2011) requires ADEQ to develop and distribute five-day advance air quality dust forecasts for High Risk Days for dust generation. Subscribe to receive the forecasts via email or text. Unpermitted sources, including Off Highway Vehicles, are required to use best practices to reduce dust. It required ADEQ to develop a Dust Action General Permit, which was issued December 30, 2011, to require best management practices from unpermitted sources to prevent exceedances on high risk days. It also added recordkeeping and reporting requirement for agricultural BMPs. ADEQ intends to submit the Replacement Five Percent Plan in early 2012.

For more information, please contact Diane Arnst - (602) 771-2375.