UNITED STATES ENVIRONMENTAL PROTECTION AGENCY REGION IX 75 Hawthorne Street San Francisco, CA 94105·3901

OFFICE OF THE REGIONAL ADMINISTRATOR 

## JUN 2 9 2011 The Honorable Dr. Clinton M. Pattea President Fort McDowell Yavapai Nation P.O. Box 17779 Fountain Hills, Arizona 85269
Dear President Pattea: Thank you for yourrecommendation on the air quality designation for the revised primary National Ambient Air Quality Standard (NAAQS) for nitrogen dioxide (N02 ) on behalfofthe Fort McDowell Yavapai Nation. This letter is to notify you ofthe U.S. Environmental Protection Agency's (EPA's) preliminary decision to designate the Fort McDowell Yavapai Nation as unclassifiable/attainment and to inform you ofour approach for completing the designations for the revised N02NAAQS. On January 22, 2010, the EPA strengthened the health-based NAAQS for N02by setting a new I-hour N02 standard at the level of 100parts perbillion (ppb). The EPA also retained with no change, the annual average N02standard of53 ppb. This suite ofstandards will protect public health by limiting people's exposures to short-tenn peak concentrations ofN02and by limiting community-wide N02 concentrations to levels below those that have been linked to respiratory-related emergency department visits and hospital admissions in the United States.
In our November 2010 letter to you requesting designation recommendations, the EPA stated that it expected to designate most areas as ''unclassifiable,'' indicating that there are insufficient data to detemtine whether or not an area is attaining the revised N02NAAQS. This approach took into account that the new monitoring network requirements established with the revised N02NAAQS will not be in place until January 2013 and that air quality data from these new monitors would not be available to inform these initial designations. TheEPA has reviewed yourrecommendations and intends to designate the Fort McDowell Yavapai Nation "unclassifiable/attainment" rather than "unclassifiable." While the EPA acknOWledges that the existing N02monitoring network does not provide adequate evidence to detemtine whether ornot the new NAAQS is met in all areas, there currently is no evidence ofviolations anywhere. The "unclassifiable/attainment" designation betterreflects the current air quality conditions. The EPA intends to redesignate areas, as appropriate, after sufficient air quality data from the new monitoring network are available. Ifyou have additional infonnation that you want the EPA to considerwith respect to the designation of the FortMcDowell Yavapai Nation, please submit it to us by August 29,2011. We are also making the EPA's preliminary designation decisions and supporting documentation available to the general public for review. We are accepting public comments on ourpreliminary decisions for 30days after a notice

Pnnlt'd on**R~cycl~d Pap~r** announcing the public commentperiod is published in the FederalRegister. We will review any information we receive from you and the general public by this date, and we plan to promulgate the final designations by October 31, 2011.
We lookforward to a continued dialogue with you and your staffas we work together to implement the 2010 NO

### zNAAQS. Should you have any questions, please do not hesitate to call me, or have your staff contactColleen McKaughan ofmy staffat 520-498-0118. Sincerely,

cc: Mark Frank, Environmental Specialist