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Air Quality Division: Plans: Particulate Matter - Phoenix Nonattainment Area

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 (PCAQCD), 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. ADEQ is responsible for air quality plans for the rest of Pinal County, which are implemented and enforced by PCAQCD and ADEQ.

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, including the Agricultural Best Management Practices (AgBMP) Program as meeting both BACM and MSM requirements, 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 2, 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

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 a SIP revision providing for annual reductions of PM10 or PM10 precursors of not less than 5% 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 deadline. The SIP revision contained rule revisions in Maricopa County (Rules 310, 310.01, and 316) and Pinal County (Chapter Four, Pinal County Code) to further reduce PM10 emissions. 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 continues to work with U.S. EPA on implementation of the Exceptional Events Rule to identify exceedances 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 rules 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. 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 comment period on the Draft MAG 2012 Five Percent Plan for PM10 for the Maricopa county Nonattainment Area culminated in a public hearing on April 12, 2012. The Proposed 2012 Five Percent Plan for PM10 for the Pinal County Township 1 North, Range 8 East Nonattainment Area portion of the metropolitan Phoenix Nonattainment Area public comment period culminated in a public hearing on April 24, 2012.

The replacement Five Percent Plans 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) required ADEQ to develop and distribute five-day advance air quality dust forecasts to identify High Risk Days for dust generation. Subscribe to receive the forecasts via email or text. House Bill 2208 required unpermitted sources, including Off Highway Vehicles, are required to use best practices to reduce dust. The bill also 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. ADEQ submitted the replacement Five Percent Plans to U.S. EPA on May 25, 2012.