UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

REGION 10 

1200 Sixth Avenue. Suite 900 


S~attle. WA 98101-3140 


JAN 9 2009 REGIONAl ADMINISTRATOR 

CERTIFIED MAIL - RETURN RECEIPT REQUESTED 

The Honorable C. L. "Butch" Otter 

Governor ofIdaho 

Post Office Box 83720 

Boise, Idaho 83720 

Dear Governor Otter: 

On March 12, 2008 the Environmental Protection Agency revised the national ambient 

air quality standards (NAAQS) for ozone to provide increased protection ofpublic 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 bfthe health 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 ofserious 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 ofpromulgation ofa new or revised NAAQS, section 1 07(d)(1 )(A) of 

the Clean Air Act requires the Governor ofeach state to submit to EPA a list ofall 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 

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 ofozone. 

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 ofyour 

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 coniment on any modifications EPA proposes to their recommendations. In . 

accordance with section 107(d)(1)(B) ofthe Clean Air Act, we intend to issue final designations 

by March 12,2010 (although that deadline may be extended up to one additional year ifEPA 

detennines that insufficient 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 ofdesignation. 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 standards in a timely manner. Ifyou have any questions, please do not 

hesitate to contact me. Your air quality staffmay wish to contact State and Tribal Air Program 

Manager, Mahbubul Islam at (206) 553-6985 or Krishna Viswanathan at (206) 553-2684. 

Sincerely, 

Elin 

'i~ D. Miller 

Regional Administrator 

. Enclosure 

00: Ms. Toni ~ardesty 

Director, Idaho Department 


of Environmental Quality 


Mr. Martin Bauer 


Administrator, Division ofAir Quality 


Idaho Department ofEnvironmental Quality