The Honorable Edmund G. Brown

State Capitol Building, Suite #1173

Sacramento, California 95814

Dear Governor Brown:

Thank you for your staffs recommendations dated June 20, 2011 on air quality designations for the state

of California 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 orrevised 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 2009-2011 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 ofstakeholders, 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/airguality/sulfurdioxide/implernent.html. The EPA will continue

to work closely with you and our other partners at the state, tribal and local levels to ensure healthprotective, common sense implementation ofthe 1-hour SO2standard.

The EPA’s review ofthe most recent monitored air quality data from 2009-2011 shows no violations of

the 2010 SO2standard in any areas in California. Consequently, the EPA is not yet prepared to propose designation action in California and is therefore currently deferring action to designate areas in

California. The EPA expects to be able to proceed with designation action in California once additional

data are gathered pursuant to our comprehensive implementation strategy. In a separate future action or

Printed on Recycled Paper
415

947

8715, or jordan.deborah@epa.gov.

Sincerely,

tfr1_Jad Blumenfeld

cc: Matthew Rodriguez, Secretary, California Environmental Protection Agency

Mary Nichols, Chairman, California Air Resources Board

James Goldstene, Executive Officer, California Air Resources Board

Lynn Terry, Deputy Executive Officer, California Air Resources BoardKaren Magliano, Chief, Air Quality Data Branch, Planning and Technical Support Division,

California Air Resources Board

Kenneth Koyama, Executive Director, California Air Pollution Control Officers Association

Gina McCarthy, Assistant Administrator for Air and Radiation

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