UNITED STATES ENVIRONMENTAL PROTECTION AGENCY REGION 8

Ref: 8P-AR The Honorable Jack Dalrymple Governor ofNorth Dakota State Capitol Bismarck, North Dakota 58505

Dear Governor Dalrymple: 1595Wynkoop Street DENVER, CO 80202-1129 Phone 800-227-8917 http://www.epa.gov /region08 

### FEB 062013

Thank you for your recommendations dated May 25, 2011, on air quality designations for the state of North Dakota for the 2010 revisionto the primary National Ambient Air Quality Standard for sulfur dioxide (S02). Reducing levels ofsulfur dioxide pollution is an important part ofthe U.S. Environmental Protection Agency's (EPA) commitmentto a clean, healthy environment. Exposure to S02 can cause a range ofadverse 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 S02by establishing a standard for 1-hour average S02 concentrations at a level of75 parts per billion. The Clean AirAct requires the EPAto complete the initial designations process within two years ofpromulgating a new or revised standard. Ifthe Administratorhas insufficient informationto make these designations, the EPA has the authority to extendthe designation process by up to one year. On July 27,2012,the EPA announced that it had insufficient informationto 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 S02 standard. 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 ofS02. The strategy is available at: http:/ /www.epa.gov/airquality/sulfurdioxide/implement.html. The EPA will continue to work closely with you and ourotherpartners at the state, tribal and local levels to ensure health-protective, commonsense implementation ofthe 1-hour S02 standard. The EPA'sreview ofthe most recent monitored air quality data from 2009-2011 shows no violations of the 2010 S02 standard in any areas in North Dakota. Consequently, the EPA is not yet preparedto propose designation action in North Dakota, and is, therefore, currently deferring action to designate areas in North Dakota. The EPA expects to be able to proceed with designation action in North Dakotaonce additional data are gathered pursuantto our comprehensive implementation strategy. In a separate future action or actions the EPA will notify you ofour intended designations for these areas, and seek public comment onthese actions, no later than 120 days priorto promulgating any final designations.

We look forward to a continued dialogue with you and your staffas we work togetherto implementthe 2010 primary S02 standard. For additional information regarding initial designations onthe S02 standard, please visit our website at www.epa.gov/so2designations. Shouldyouhave any questions, please do not hesitate to call me, orhave your staffcontact Crystal Ostigaard ofmy staffat (303) 312-6602 or ostigaard.crystal@epa.gov.

Enclosure

cc: David Glatt, Section Chief, NDDH Terry O'Clair, Director, NDDH Sincerely,

# ~"~~~**~** Regional Administrator

Gina McCarthy, Assistant Administrator for Air and Radiation StephenD. Page, Director, Office ofAir Quality Planning and Standards