UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
REGION IX 75 Hawthorne Street San Francisco, CA 94105-3901

OFFICE OF THE REGIONAL ADMINISTRATOR

The Honorable Jim Gibbons Governor of Nevada 10 1North Carson Street Carson City, Nevada 89701

Dear Governor Gibbons:

On March 12,2008,the Environmental ProtectionAgency (EPA) 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 demonstratedat 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 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 one year of promulgationof 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 12,2009with respect to the revised ozone NAAQS. Establishing area designationsis 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 standardswill be required to adopt plans to reduce ambient concentrations of ozone.

The enclosed memorandumprovides guidanceto 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 120days prior to promulgating final designations. Following the announcementof intended designations, states and tribes will have the opportunity to comment on any modifications EPA proposes to their recommendations. 

### In accordancewith section 107(d)(l)(B) of the Clean Air Act, we intend to issue final designationsby March 12,2010 (although that deadline may be extended up to one additionalyear if EPA determinesthat insufficient information is

Printed on Recycled Paperavailable to establish designations by that date). Our designationswill 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 nonattainment areas under the 2008 revised ozone NAAQS will be established through a separatenotice-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 contact Deborah Jordan, Air Division Director, at 415-947-8715, or have your staff contact Lisa Hanf, Air Planning Office Chief, at 415-972-3854.
Sincerely,

D$ayne Nastri

Regional Administrator

Enclosure

cc: Leo Drozdoff, Administrator,Nevada Departmentof Environmental Protection Colleen Cripps, Deputy Administrator,Nevada Departmentof Environmental Protection Andrew Goodrich, Division Director, Air Quality Management Division, Washoe County District Health Department Lewis Wallenmeyer, Director, Clark County Department of Air Quality and Environmental Management