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# \~} "II.**Pfl.O~C"** UNITED STATES ENVIRONMENTAL PROTECTION AGENCY REGION 8 1595Wynkoop Street DENVER, CO 80202-1129 Phone 800-227-8917 http://www.epa.gov/region08



# JUN 29 2011

Ref: 8P-AR

The Honorable Jack Dalrymple Governor ofNorth Dakota State Capitol Bismarck, North Dakota 58505

Dear Governor Dalrymple:

Thank you for North Dakota's recommendations on air quality designations for the revised primary National Ambient Air Quality Standard (NAAQS) for nitrogen dioxide (N02) throughoutNorth Dakota. This letter is to notify you ofthe U.S. Environmental Protection Agency's (EPA's) response to North Dakota's designation recommendations, and to inform you ofour approach for completing the designations for the revised N02NAAQS.

On January 22, 2010, the EPA strengthened the health-based National Ambient Air Quality Standard for N02by setting a new I-hourN02standard 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 protect public health by limiting people's exposures to short-term peak concentrations ofN02and by limiting community-wide N02concentrations to levels below those that have been linked to respiratory-related emergency department visits and hospital admissions in the United States. To determine compliance with the new standard, the EPA established new ambient air monitoring and reporting requirements for N02

. In urban areas, monitors are required near major roads as well as in other locations where maximum concentrations are expected. Additional monitors will be required in some large urban areas to measure the highest concentrations ofN02that occur more broadly across communities.

In the preamble to the 2010 N02NAAQS and in the EPA's October 2010 letter to yourpredecessor requesting designation recommendations, the agency stated that it expected to designate most areas of the country as "unclassifiable," indicating thatthere are insufficient data to determine 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 effective until January 2013 and that air quality data from these new monitors would not be available to inform these initial designations.
The agency has reviewed North Dakota's recommendations and others, and intends to designate all
areas ofNorth Dakota, as well as the rest ofthe country, as "unclassifiable/attainment"rather than "unclassifiable." Based on air quality data from 2008-2010, all monitored areas in the country meet the 20 10 N02NAAQS. While we acknowledge that the existingN02monitoring network does not provideadequate evidence to detennine whether or not the new NAAQS is met in all areas, there currently is no evidence ofviolations anywhere in the country. The "unclassifiable/attainment" designation better reflects the current air quality conditions. We plan to redesignate areas, as appropriate, after sufficient air quality datafrom the new monitoring network are available.

We will designate North Dakotaunclassifiable/attainment using the boundaries North Dakota recommended to the EPA or revised boundaries you may provide in response to this letter. In past designations for N02 , for the majority ofstates, the area ofthe state where the air quality could not be classified, orwas better than the national standards, was given a statewide, or rest-of-state designation. However, we recommend that you carefully consider the implications for the Prevention ofSignificant Deterioration (PSD) permittingprogram ofhaving the entire state designated as a single area rather than smaller areas (e.g., counties, groups ofcounties, etc.). To ensure that the size ofdesignated areas is consistent with your state'sobjectives for managing air quality deterioration and economic growth, we recommend that yourpermitting staffbe consulted on the area boundary issues.

Ifyou have additional infonnation that you want the EPA to consider with respect to the EPA's designation, 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 announcing the public comment period is published in the 

### FederalRegister. We will review any infonnation'we receive from the state ofNorth Dakota 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 staffas we work together to implement the 2010 N02 NAAQS. Should you have any questions, please do not hesitate to call me, or have your staff contactCarl Daly ofmy staffat (303) 312-6416.

Sincerely,

es B. Martin R gional Administrator

cc: L. David Glatt, Chief, EHS Terry O'Clair, Director, Air Quality

GinaMcCarthy, Assistant Administrator for Air and Radiation Stephen D. Page, Director, Office ofAir Quality Planning and Standards