UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

REGION 10

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1200 Sixth Avenue, Suite 900

2^^ \oa Seattle, Washington 98101-3140

OFFICE OF THE

REGIONAL ADMINISTRATOR

JUN 2 9 2011

The Honorable Christine Gregoire

Governor of the State of Washington

Post Office Box 40002

Olympia, Washington 98504-0002

Dear Governor Gregoire:

Thank you for your recommendations on air quality designations for the revised primary National

Ambient Air Quality Standard (NAAQS) for nitrogen dioxide (NO 2) throughout Washington. This letter

is to notify you of the U.S. Environmental Protection Agency's (EPA's) response to Washington's

designation recommendations, and to inform you of our approach for completing the designations for

the revised NO2 NAAQS.

On January 22, 2010, the EPA strengthened the health-based National Ambient Air Quality Standard

(NAAQS) for NO2 by setting a new 1-hour NO2 standard at the level of 100 parts per billion (ppb). This

new standard will protect against adverse health effects associated with short-term exposure to NO 2 ,

including respiratory effects that can result in 'd sion to a hospital. The EPA also retained with no

change, the an a1 average NO2 4andard•of'55 ppp This suite of standards will protect public health by

limiting people's exposures to short-term peak concentrations of NO2 and by limiting community-wide

NO2 concentrations 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 NO2. 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 of NO2 that occur more broadly across communities.

In the preamble to the 2010 NO2 NAAQS and in the EPA's October 2010 letter to you requesting

designation recommendations, the Agency stated that it expected to designate most areas of the country

as "unclassifiable," indicating that there are insufficient data to determine whether or not an area is

attaining the revised NO2 NAAQS. This approach took into account that the new monitoring network

requirements established with the revised NO2 NAAQS 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 your recommendations and others, and intends to designate all areas of

Washington, as well as the rest of the country, as "unclassifiable/attainment" rather than

"unclassifiable." Based on air quality data from 2008-2010, all monitored areas in the country meet the

2010 NO2 NAAQS. While the EPA acknowledges that the existing NO2 monitoring network does not

provide adequate evidence to determine whether or not the new NAAQS is met in all areas, there

currently is no evidence of violations anywhere in the country. 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.
The EPA intends to designate Washington unclassifiable/attainment using the boundaries Washington

recommended to the EPA or revised boundaries you may provide in response to this letter. In past

designations for NO2 , for the majority of states, the area of the state where the air quality could not be

classified, or was better than the national standards, was given a statewide, or rest-of-state designation.

However, the EPA recommends that your state carefully consider the implications for the Prevention of

Significant Deterioration (PSD) permitting program of having the entire state designated as a single area

rather than smaller areas (e.g., counties, groups of counties, etc.). To ensure that the size of designated

areas is consistent with your state's objectives for managing air quality deterioration and economic

growth, we recommend that your permitting staff be consulted on the area boundary issues.

If your state has additional information 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 Federal Register. We will review any information we receive

from the State of Washington 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 NO2 NAAQS. Should you have any questions, please do not hesitate to call me, or have your staff

contact Claudia Vaupel at 206-553-6121.

Sincerely,

Dennis J. McLerran

Regional Administrator

cc: Ted Sturdevant

Director, Washington State Department of Ecology

Stu Clark

Air Program Director, Washington State Department of Ecology

Gina McCarthy

Assistant Administrator for Air and Radiation, EP A

Stephen D. Page

Director, Office of Air Quality Planning and Standards, EPA