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 your recommendation on the air quality designation for the revised primary National 

Ambient Air Quality Standard (NAAQS) for nitrogen dioxide (N02) on behalf of the Fort McDowell 

Yavapai Nation. This letter is to notify you of the U.S. Environmental Protection Agency's (EPA's) 

preliminary decision to designate the Fort McDowell Yavapai Nation as unclassifiable/attainment and to 

inform you of our approach for completing the designations for the revised N02 NAAQS. 

On January 22, 2010, the EPA strengthened the health-based NAAQS for N02 by setting a new I-hour 

N02 standard at the level of 100 parts per billion (ppb). The EPA also retained with no change, the 

annual average N02standard of 53 ppb. This suite of standards will protect public health by limiting 

people's exposures to short-tenn peak concentrations of N02and 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 N02 NAAQS. This approach took into account 

that the new monitoring network requirements established with the revised N02 NAAQS 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. 

The EPA has reviewed your recommendations 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 or not the 

new NAAQS is met in all areas, there currently is no evidence of violations anywhere. The 

"unclassifiable/attainment" designation better reflects 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. 

If you have additional infonnation that you want the EPA to consider with respect to the designation of 

the Fort McDowell 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 our preliminary decisions for 30 days after a notice 

Pnnlt'd on R~cycl~d Pap~r
announcing the public comment period is published in the Federal Register. 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 look forward to a continued dialogue with you and your staff as we work together to implement the 

2010 NOz NAAQS. Should you have any questions, please do not hesitate to call me, or have your staff 

contact Colleen McKaughan of my staff at 520-498-0118. 

Sincerely, 

cc: Mark Frank, Environmental Specialist