UNITED STATES ENVIRONMENTAL PROTECTION AGENCY REGION 8 1595WYNKOOP STREET DENVER, CO 80202-1129 Phone 800-227-8917 http://www.epa.gov/region08 8P-AR 

# 'JUN 14 2011.

Steven M. Pimer Secretary Department ofEnvironment andNatural Resources Joe Foss Building, 523 East Capitol Pierre, SouthDakota 57501-3182

Dear Mr. Pimer: Thank you for your recommendations onair quality designations for the revised National Ambient Air Quality Standards for lead throughout South Dakota. This letter is to notify you of the U.S. Environmental Protection Agency's (EPA's)preliminary decision to designate all of South Dakota as attainment/unclassifiable, and to inform you ofour approach for completing the designations for the revised lead standards. Reducing levels oflead pollution is an important part ofthe EPA's commitmentto a clean, healthy environment. Lead exposure can cause a range of adverse health effects, most notably in children. Exposures to low levels oflead early in life have been linked to effects on IQ, learning, memory, and behavior. On October 15, 2008, the EPA substantially strengthenedthe health-based or "primary"National Ambient Air Quality Standard by**lowerin~** it from 1.5 micrograms per cubic meter (llg/m3)
- a level set in 1978

- to a level of0.15 Ilg/m

.This stronger standard provides increased protection against adverse health effects associated withexposure to lead in at-risk groups, including children. To provide increased protectionagainst lead-related environmental and other welfare effects, the EPA revised the secondaryNational AmbientAir Quality Standard to be identical in all respects to the revised primary standard. The EPA also determinedthat the pre-existing ambient lead monitoring network was inadequate for determining whether many areas are meeting the revised lead standard and established new criteria for siting ambient lead monitors and new datacollectionrequirements. Monitors meeting the new network siting requirements were to begin operationJanuary 1,2010. Withintwo years ofpromulgating new orrevised National Ambient Air Quality Standards, the Clean AirAct requires the EPA to complete the initial process ofidentifying or designating areas that meet ordo not meet an air quality standard. Ifthe Administratorhas insufficient information to make these designations, the EPA has the authority to extendthe designationprocess by up to one year. In light ofthe new monitoring network, the EPA is completing the lead designations in two rounds. In the first round, published onNovember 16, 2010, the EPA designated as "nonattainment" 16 areas as violating the 2008 LeadNational Ambient Air Quality Standardsbased on data from the pre-2010 monitoring network. For all other areas, the EPA extendedthe deadline for designations by up to one year so that data from the newly deployed monitors canbe considered in making appropriate designation decisions. States were given an opportunity to update theirrecommendation letters for those remaining areas for our consideration inthe second round ofdesignations by December 15,2010. The EPA intends to complete the second round of lead designations by no laterthan October 14, 2011. Consistent with the Clean Air Act, and after carefully considering South Dakota's October 15, 2009 recommendation letter, and all the associated technical information for the 2008 Lead National Ambient Air Quality Standards, including the most recent air quality data from 2008­ 2010, the EPA is proposing to designate South Dakotaas unclassifiable/attainment. The EPA uses this designation for initial designations to identify areas that have data indicating attainment, orwhere there is no evidence ofa violation. Ifyour state has additional information thatthe EPA should consider with respect to our proposed modification to your designation recommendation, please submit it to us by August 15, 2011. The EPA'spreliminary designation decisions and supporting documentation will be made available to the general public for review. We will be accepting commentsthrough August 15,2011. We will review any information we receive from the state ofSouth Dakotaand the general public by this date, and we planto promulgate the second round offinal designations by October 14,2011. We look forward to a continued dialogue with you and your staffas we worktogetherto implementthe 2008 Lead National AmbientAir Quality Standards. Should you have any questions, please do not hesitate to call me, orhave your staffcontact Carl Daly ofmy staffat (303) 312-6416. Sincerely,

cc: Brian Gustafson, Administrator Air Quality Program South Dakota Department ofEnvironment and Natural Resources

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