___

) UNITED STATES ENVIRONMENTAL PROTECTION AGENCY I
REGION
IX PRO1

75 Hawthorne Street San Francisco, CA 94105-3901
OFFICEOFTHE FEB
062013 REGIONALADMINISTRATOR The Honorable Janice Brewer 1700 West Washington Street Phoenix, Arizona 85007 Dear Governor Brewer: Thank youfor yourrecommendations dated May 25, 2011 onair 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 SO 2 pollution

is an important part of the U. S. Environmental Protection Agency’s (EPA) commitment

to a clean, healthy environment. Exposure
to SO 2 cancause
a rangeof adverse health effects, including narrowing of the airways which cancause difficulty breathing and increased asthma symptoms. This letter is to notify you of the EPA’s preliminary intentions regarding yourrecommended designations. On June 3, 2010, the EPA strengthened the health-based

or “primary” standard for SO 2 by establishing

astandard for 1-hour averageSO 2 concentrations

at alevel of 75 parts perbillion. The Clean Air Act requires the EPA to complete the initial designations processwithin two years of promulgating

aneworrevised standard. If the Administrator has insufficient information

to make these designations, the EPA has the authority
to extend the designation process by upto one year.On July 27, 2012, the EPA announced that it had insufficient information

to complete the designations for the 1-hour SO2 standard within two yearsand extended the designations deadline
to June 3, 2013. At this time the EPA is proceeding with designating

asnonattainment most areasin locations where existing monitoring data from 2009-20

1 1 indicate violations of the 1-hour SO 2 standard. The EPA intends to address the designations for all other areasin separate future actions. With input from
adiverse groupof stakeholders, EPA has developed

a comprehensive implementation strategy for these future actions that focuses resourceson identifying and addressing unhealthy levels of SO 2 .The strategy
is available at:www.epa.gov/airquality/sulfurdioxide/iinplement.html. The EPA will continue
to work closely with youand ourother partners
at the state, tribal and local levels to ensure health-protective, commonsense implementation

of the 1-hour SO 2 standard. Consistent with the Clean Air Act, after carefully considering Arizona’s recommendations
and all of the associated technical information for the 2010 SO 2 standard, including the most recent air quality data from 2009-2011, the EPA intends to agreewith yourrecommendation

to PrintedonRecycled Paperdesignate
as nonattainment the following areas, including the following counties or portions of counties: Nonattainment Area County Hayden
Gila County (p), Pinal County (p) Miami
Gila County (p) Q,)

indicates portion of county 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 of the 2010 SO 2 standard 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 SO 2 standard. For additional information regarding initial designations
of the SO 2 standard, 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