The Honorable Janice Brewer

1700 West Washington Street

Phoenix, Arizona 85007

Dear Governor Brewer:

Thank you for your recommendations dated May 25, 2011 on air quality designations for the

state of Arizona for the 2010 revision to the primary National Ambient Air Quality Standard for sulfur dioxide (SO 2).Reducing levels of SO2pollution is an important part ofthe U. S. Environmental Protection Agency’s (EPA) commitment to a clean, healthy environment.

Exposure to SO2can cause a range of adverse health effects, including narrowing ofthe airways which can cause difficulty breathing and increased asthma symptoms. This letter is to notify you ofthe EPA’s preliminary intentions regarding your recommended designations.

On June 3, 2010, the EPA strengthened the health-based or “primary” standard for SO2by establishing a standard for 1-hour average SO2concentrations at a level of 75 parts per billion. The Clean Air Act requires the EPA to complete the initial designations process within two years of promulgating a new or revised standard. Ifthe Administrator has insufficient information to

make these designations, the EPA has the authority to extend the designation process by up to

one year. On July 27, 2012, the EPA announced that it had insufficient information to complete the designations for the 1-hour SO2standard within two years and extended the designations deadline to June 3, 2013.

At this time the EPA is proceeding with designating as nonattainment most areas in locations

where existing monitoring data from 2009-20 1 1 indicate violations ofthe 1-hour SO2standard.

The EPA intends to address the designations for all other areas in separate future actions. With input from a diverse group of stakeholders, EPA has developed a comprehensive implementation strategy for these future actions that focuses resources on identifying and addressing unhealthy levels of SO2.The strategy is available at:www.epa.gov/airquality/sulfurdioxide/iinplement.html. The EPA will continue to work closely with you and our other partners at the state, tribal and

local levels to ensure health-protective, common sense implementation ofthe 1-hour SO2

standard.

Consistent with the Clean Air Act, after carefully considering Arizona’s recommendations and

all of the associated technical information for the 2010 SO2standard, including the most recent air quality data from 2009-2011, the EPA intends to agree with your recommendation to

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If you have additional information that you would like the EPA to consider, please submit it to us

by April 8, 2013. We also will be publishing a notice in the Federal Register announcing a 30-day period for the public to provide input on EPA’s preliminary designation decisions regarding

the areas that we would designate as nonattainment based on monitoring data. We intend to

promulgate these designations for areas with monitored violations ofthe 2010 SO2standard by

June 2013. We are not yet prepared to propose designations action or seek public comment on

other areas.

We look forward to a continued dialogue with you and your staff as we work together to

implement the 2010 primary SO2standard. For additional information regarding initial

designations ofthe SO2standard, please visit our website at: www.epa.gov/so2designations.

Should you have any questions, please do not hesitate to call me, or have your staff contact

Deborah Jordan, Director, Air Division at 415-947-8715, or jordan.deborah(iiepa.gov.

Sincerely,

-1&t1 kL

Jared Blumenfeld

Enclosure

cc: Henry Darwin, Director, Arizona Department of Environmental Quality

Eric Massey, Director, Air Quality Division, Arizona Department of Environmental Quality

Don Gabrielson, Director of Pinal County Air Quality Control District

Gina McCarthy, Assistant Administrator tbr Air and Radiation

Stephen D. Page, Director, Office of Air Quality Planning and Standards