UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

REGION 5 

77 WEST JACKSON BOULEVARD 

CHICAGO. IL 60604-3590 

DEC 2 3 2008 

REPLY TO THE ATTEN7'@N OF 

R-19J 

Honorable Tim Pawlenty 

Governor of Minnesota 

Saint Paul, Minnesota 55 155 

Dear Governor Pawlenty: 

On March 12,2008, the U.S. Environmental Protection Agency revised the national 

ambient air quality standards (NAAQS) for ozone to provide increased protection of public 

health and welfare from ozone pollution. The new primary ozone standard was lowered from 

0.08 parts per million (ppm) to 0.075 ppm based on numerous epidemiological studies conducted 

during the past decade in which many of the health effects associated with ozone exposure have 

been demonstrated at and below the level of the 0.08 ppm standard, which was promulgated in 

1997. These include a range of serious respiratory effects and increased premature mortality. 

EPA also strengthened the secondary 8-hour ozone standard, making it identical to the revised 

primary standard, to protect against welfare effects such as impacts on vegetation and forested 

ecosystems. 

Within one year of promulgation of a new or revised NAAQS, section 107(d)(l)(A) of 

the Clean Air Act requires the Governor of each state to submit to EPA a list of all areas in the 

state, recommending designations for each as "attainment," "nonattainment," or "unclassifiable" 

with respect to the new or revised standard. Therefore, we ask that you provide your designation 

recommendations, including appropriate area boundaries, to EPA by March 12,2009, with 

respect to the revised ozone NAAQS. Establishing area designations is a key step in the process 

of providing the health protections that the Clean Air Act mandates. Areas that are designated as 

not attaining the air quality standards will be required to adopt plans to reduce ambient 

concentrations of ozone. 

The enclosed memorandum provides guidance to state and local air pollution control 

agencies and Tribes on the process for designating areas under the 2008 revised ozone standard. 

We plan to announce our intended designations as early as possible after receipt of your 

recommendations, but no later than 120 days prior to promulgating final designations. 

Following the announcement of intended designations, states and Tribes will have the 

opportunity to comment on any modifications EPA proposes to their recommendations. In 

accordance with section 107(d)(l)(B) of the Clean Air Act, we intend to issue final designations 

by March 12,201 0 (although that deadline may be extended up to one additional year if EPA 

determines that insuflicient information is available to establish designations by that date). Our 

designations will be based on the most recent 3 years of certified, quality assured monitoring 

data available. Ozone nonattainment areas will be classified at the time of designation. The 

approach EPA will use to classify nonattainrnent areas under the 2008 revised ozone NAAQS 

will be established through a separate notice-and-comment rulemaking. 
We look forward to working with you and your staff to develop area designations under 

the 2008 revised ozone standards in a timely manner. If you have any questions, please do not 

hesitate to contact me. Your air quality staff may wish to contact Cheryl L. Newton, Director, 

Air and Radiation Division, at 3 12-353-22 12. 

Sincerely, 

&\ 

Lynn Buhl 

Regional Administrator 

Enclosure 

cc: David Thornton, Assistant Commissioner 

Minnesota Pollution Control Agency