UNITED STATES ENVIRONMENTAL PROTECTION AGENCY REGION 5 77 WEST JACKSON BOULEVARD CHICAGO, IL 60604-3590

Honorable Jennifer M. Governor ofMichigan 

## DEC 

## 2 3 

## 2008

Granholm REPLY TO THE ATTENTION OF

R-19J

Lansing, Michigan 48909

Dear Governor Granholm:

On March 12,2008,the U.S. Environmental Protection Agency revised the national ambient air quality standards (NAAQS) for ozone to provide increased protection ofpublic health and welfare fiom ozonepollution. 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 thehealth effects associated with ozone exposure have been demonstrated at and below the level ofthe 0.08 ppm standard, which was promulgated in 1997. These include a range of seriousrespiratory effects and increased premature mortality. EPA also strengthenedthe 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 oneyear ofpromulgation of a new orrevised NAAQS, section 107(d)(l)(A)of the Clean Air Act requires the Governor ofeach stateto 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 ozoneNAAQS. Establishing area designations is a key step in the process ofproviding 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 ofintended 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)ofthe 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 insufficientinformation is available to establish designations by that date). Our designations will be based on the most recent 3 years ofcertified, quality assured monitoring data available. Ozone nonattainment areas will be classified at the time of designation. The approach EPA will use to classify nonattainment 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 standardsin 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 312-353-2212.
Sincerely,

I I 1-7 " Lynn Buhl Regional Administrator

Enclosure

cc: Steven E. Chester, Director Michigan Department 

### of EnvironmentalQuality