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 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. 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 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 promulgation of 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 12,2009 with 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 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 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 Clean Air Act, we 

intend to issue final designations by March 12, 2010 (although that deadline may be 

extended up to one additional year if EPA determines that insufficient information is 

Printed on Recycled Paper 
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 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 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 Department of Environmental Quality 

Nancy Wrona, Director, Air Quality Division, Arizona Department of 

Environmental Quality 

Lawrence Odle, Director, Maricopa County Air Quality Department 

Don Gabrielson, Director, Pinal County Air Quality Control District 

Ursula Kramer, Director, Pima County Department of Environmental Quality