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

OFFICE OF THE REGIONAL ADMINISTRATOR 

## JUN 2 9 2011

The Honorable Virgil Moose Chairperson Big Pine Paiute ShoshoneTribe ofthe Owens Valley Post Office Box 700 841 South Main Street Big Pine, California 93513
Dear Chairman Moose: Thankyou for your recommendation on the air quality designation for the revised primary National AmbientAir Quality Standard (NAAQS) for nitrogen dioxide (N02 ) on behalfofthe Big Pine Paiute ShoshoneTribe ofthe Owens Valley. This letter is to notify you ofthe U.S. Environmental Protection Agency's (EPA's) preliminary decision to designate the Big Pine Reservation as unclassifiablel attainment and to inform you ofour approach for completing the designations for the revised N02 NAAQS.
On January 22,2010, the EPA strengthened the health-based NAAQS for N02by setting a new I-hour N02standard at the level of 100 parts per billion (ppb). The EPA also retained with no change, the annual average N02standard of53 ppb. This suite ofstandards will protectpublic health by limiting people's exposures to short-term 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 November2010 letter to you requesting designation recommendations, the EPA stated that it expected to designate most areas as "unclassifiable," indicating that there are insufficientdata to determine whether ornot an area is attaining the revised N02 NAAQS. This approach took into account that the new monitoring networkrequirements 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. The EPA has reviewed yourrecommendations and intends to designate the Big Pine Reservation as "unclassifiable/attainment"rather than "unclassifiable."While the EPA acknowledges that the existing N02monitoring network does not provide adequate evidence to determine whether or not the new NAAQS is met in all areas, there currently is no evidence ofviolations anywhere. The "unclassifiablel attainment" designation betterreflects the current air quality conditions. The EPA intends to redesignate areas, as appropriate, after sufficient airquality data from the new monitoring network are available. Ifyou have additional information that you want the EPA to consider with respect to the designation of the Big Pine Reservation, please submitit 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

Printed on Rt'cyded Paperreview. We are accepting public comments on ourpreliminarydecisions for 30 days after a notice announcing the public commentperiod 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.
Welook forward to a continued dialogue with you and your staffas we work together to implement the 2010 N02 NAAQS. Should you have any questions, pleasedo not hesitate to call me, or have your staff contact Colleen McKaughan ofmy staffat 520-498-0118. Sincerely,

cc: Ms. Sally Manning, Environmental Director