The Honorable Brian Sandoval

State Capitol Building

101 North Carson Street

Carson City, Nevada 89701

Dear Governor Sandoval:

Thank you for your staff’s recommendations dated May 3, 2011 on air quality designations for the state ofNevada 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 nanowing 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 11 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/implement.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 of the 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 Nevada. Consequently, the EPA is not yet prepared to propose designation action in Nevada and is therefore currently deferring action to designate areas in Nevada. The EPA expects to be able to proceed with designation action in Nevada once additional data are

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

Printed on Recycled Paper
415-947-8715, or j ordan.deborah(epa.gov.

Sincerely,

,,4rJared Blumenfeld

cc: Colleen Cripps, Administrator, Nevada Division ofEnvironmental Protection

Mike Elges, Deputy Administrator, Nevada Division ofEnvironmental Protection

Rob Bamford, Chief, Air Quality Planning Bureau, Nevada Division of Environmental Protection

Lewis Wallenmeyer, Director, Clark County Department of Air Quality and Environmental

Management

Kevin Dick, Director, Air Quality Management Division, Washoe County Board of Health

Gina McCarthy, Assistant Administrator for Air and Radiation

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