UNITED STATES ENVIRONMENTAL PROTECTIONAGENCY REGION4 ATLANTA FEDERAL CENTER 61 FORSYTH STREET ATLANTA, GEORGIA 30303-8960 

## DEC 1 9 2008

The Honorable Haley Barbour Governor of Mississippi Sillers Building, 19th Floor 550 High Street Jackson, Mississippi 3920 1

Dear Governor Barbour:

On March 12,2008,the 

### U.S. Environmental Protection Agency (EPA) revised the national ambient air quality standards (NAAQS) for ozone to provide increased protection of public health and welfare from ozone pollution. Based on numerous epidemiological studies conducted during the past decade in which many health effects associated with ozone exposure have been demonstrated at and below the 1997 standard of 0.08parts per million (ppm), the Agency lowered the primary ozone standard to 0.075ppm. 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 followingpromulgation of a new or revised NAAQS, section 107(d)(l)(A)of the Clean Air Act (CAA) 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 EPA such designationrecommendations with respect to the revised ozone NAAQS, including appropriate areaboundaries, by March 12, 2009. Establishing area designations is akey step in the process ofproviding the health protections that the CAA mandates. Areas that are designated 

### as not attaining the air quality standards must 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 ozonestandard. 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 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 CAA, we intend to issue final designationsby March 12,201 0 (although that deadline may be extended up to one additional year, if EPA determinesthat insufficient information is available to establish designations by that date). Our designations will be based on the most recent three years of certified, quality assured available monitoring data. Ozone nonattainment areas will be classified at the time of designation. The EPA will establish its approach to classifying nonattainment areas under the 2008 revised ozone NAAQS through a separate notice-and-comment rulemaking.

Internet Address (URL) http Ilwwepa gov RecycledlRecyclable Printedw~th Vegetable Oil Based Inks on Recycled Paper (M~n~rnum 30% Postconsumer)

### We look forward to working with you and your staff to develop area designationsunder the 2008 revised ozone NAAQS in a timely manner. Ifyou have any questions, please contact
me at (404) 562-8357 or have a member ofyour staff contact Beverly Banister, Director,Air, Pesticides and Toxics Management Division, at (404) 562-9077.
Sincerely,

Regional Administrator

Enclosure
cc: Trudy D.Fisher, Exec. Director, MDEQ Jerry Cain, Director, MDEQ-OPC Maya Rao, Chief, OPC-Air Division