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



### JAN 

### 1 3 2009 OFFICE OF THE REGIONAL ADMINISTRATOR

The Honorable Janet Napolitano Governor of Arizona 1700 West Washington Phoenix, Arizona 85007

Dear Governor Napolitano:

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 0.075ppm 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 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 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 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 announcement of 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 (althoughthat deadline may be extended up to one additionalyear if EPA determinesthat insufficient information is

Printed on Recycled Paperavailableto 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 areasunder the 2008 revised ozone NAAQS will be established through a separatenotice-and-commentrulemaking.

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 415-947-87 15,or have your staff contact Lisa Hanf, Air Planning Office Chief, at 415-972-3854.
Sincerely,

ayne Nastri egional Administrator

Enclosure

cc: Stephen Owens, Director, Arizona Departmentof Environmental Quality Nancy Wrona, Director, Air Quality Division, Arizona Department of Environmental Quality Lawrence Odle, Director, Maricopa CountyAir Quality Department Don Gabrielson, Director, Pinal County Air Quality Control District Ursula Kramer, Director, Pima County Departmentof Environmental Quality