U.S. EPA FACT SHEET
EPA Approves the 2012 Five Percent Plan for PM-10 for the Maricopa County Nonattainment
Area
May 30, 2014
Summary
•	EPA is approving the 2012 Five Percent Plan for the Maricopa County Nonattainment Area
because the plan shows annual reductions of PM-10 emissions of at least five percent between
2007 and 2012 and demonstrates attainment of the PM-10 National Ambient Air Quality
Standard (PM-10 NAAQS) by December 31, 2012.
•	Today's proposal recognizes continued air quality improvement in Arizona accomplished
through the efforts of the Arizona Department of Environmental Quality (ADEQ), the
Maricopa County Air Quality Department, the Maricopa Association of Governments, multiple
industry, business and agricultural stakeholders, and EPA to protect public health.
Background
•	The nonattainment area is located in the eastern portion of Maricopa County and encompasses
the cities of Phoenix, Mesa, Scottsdale, Tempe, Chandler, Glendale, as well as the other
jurisdictions that comprise the Phoenix metropolitan area. The nonattainment area also includes
the town of Apache Junction in Pinal County.
•	The State of Arizona was required to submit a 5% PM-10 Plan (also known as a 189(d) plan)
after the Maricopa County nonattainment area failed to attain the PM-10 NAAQS by the
required attainment date of December 31, 2006.
•	The failure to attain triggered the requirements of section 189(d) of the Clean Air Act (CAA),
which requires a PM-10 reduction of five percent per year until attainment.
•	The State of Arizona originally submitted a 5% Plan to EPA on December 21, 2007, which
EPA proposed to partially disapprove due to issues with the attainment demonstration and the
emissions inventory.
•	The State of Arizona subsequently withdrew the 2007 5% Plan and resubmitted a revised plan
on May 25, 2012. This is the plan that EPA is finalizing action on today.
•	EPA was required by the terms of a consent decree with the Arizona Center for Law in the
Public Interest (ACLPI) to propose action on the plan by January 14, 2014, and finalize action
by June 2, 2014.
Particulate Matter and Public Health
•	Reducing PM-10 levels is essential because airborne particles are a serious threat to human
health. Major concerns include effects on breathing and respiratory systems, damage to lung

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tissue, cancer, and premature death. The elderly, children, and people with chronic lung disease
and asthma are especially sensitive to the effects of particulate matter.
•	A study released in 2009 by Arizona State University showed that when levels of PM-10 in
central Phoenix were high, there was a significant increase in asthma incidents in children.
Next Steps
•	EPA's final action will be effective 30 days from the date of publication in the Federal
Register.
For More Information:
http://www.epa.gov/region9/air/phoenixpm/index.html
Phoenix PM10 Trends 2002-2012
35.0 -

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