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

OFFICE OF THE REGIONAL ADMINISTRATOR 

### OCT 1 4 2009
The Honorable Arnold Schwarzenegger Governor ofCalifornia State Capitol Building Sacramento, CA 95814 Dear Governor Schwarzenegger: I am writing in follow-up to Administrator Lisa Jackson's October 8 letter notifying you that the u.S. Environmental Protection Agency (EPA) has determined that two additional areas within your state maybe violating the 2006 24-hour national ambient air quality standards (NAAQS) for fine particles (PM25). Your state submitted its initial list ofrecommendations for designations to EPA by letter from James N. Goldstene, Executive Officer, California Air Resources Board, dated December 17, 2007. Last year, EPAnotified you ofits intended modifications to those recommendations by letter from Wayne Nastri, Regional Administrator, dated August 18,2008. Your state submitted additional information regarding the designations to EPAbyletter from James N. Goldstene, dated October 15, 2008. EPAhad intended to finalize the designations decisions in December of2008. Due to the change ofAdministration, however, EPA did not completethe process at that time. Therefore, at the request ofthe new Administration, EPAhas reviewed the status ofareas for the 2006 24-hour PM2.5 NAAQS in orderto assure that the final decisions reflect currentpolicy and the most upto-date air quality monitoring data as ofthis time. In particular, this review has allowed consideration of2006-2008 air quality data for all areas. The new data indicatethat two additional areas in California, Plumas County and Shasta County, now appear to be violating the 2006 24-hour PM2
.5NAAQS, leading EPA to believethat further modifications to your state's initial recommendations may be necessary. EPAis therefore deferring the designation for Plumas and Shasta counties for the 2006 24-hour PM2
.5NAAQS so that EPA can collect and evaluate additional informationbeforepromulgating designations. We note that EPA has received requests from the Air Resources Board to exclude certain monitored violations in these counties, and documentation to support these requests, pursuant to our exceptional events rule. Forthe ShastaCounty and Plumas County areas, as for all areas where there are possible exceptional events contributing to high levels ofPM2.5, EPAwill review the data providedbythe state air quality agency. Based on that review, EPA will determine whether data for certain days were influenced by "exceptional events" and shouldbe excluded from the three-year data set used to identify these air quality violations.

Printed on Recycled PaperConsistent with the approach used to assess otherpotential nonattainment areas, EPA also intends to evaluate relevant technical data for the ring ofcounties immediately surrounding Plumas I and Shasta2counties to determine whether any ofthese nearby counties contribute to the violation. Werecognize that these are large geographical areas. Looking at the counties surrounding Plumas and Shasta counties is only a startingpoint for the evaluation; it should not be assumed that the final designated nonattainment areawill include these counties. Consideration ofthe relatively long distances across which PM2.5 and PM2

.5precursors canbe transported shouldbebalanced with a key purpose ofdesignations, which is to identifythose nearby contributing areas that should be included within a designated nonattainment areato ensurethe development ofan appropriate State Implementation Plan for the area. This is explained further in the Federal Registernotice for final 24-hour PM2
.5designations, at www.epa.gov/pmdesignations/2006standards/regs.htm#3. Factors that shouldbe considered as the basis for nonattainment areaboundaries are described in a guidance memorandum entitled "Area Designations for the Revised 24-Hour Fine Particle National Ambient Air Quality Standard" from Robert J. Meyers, dated June 8, 2007 (enclosed). When EPA's evaluation is complete, we will notify you ofourintended designations and boundaries for these areas. Following this notification, which we will provide at least 120 days priorto promulgating final designations, you will have the opportunity to comment on EPA's intended designations and to provide additional information to inform the final decision. As with the other areas in your state, EPA will work with your staffto assure that the final designations and boundaries are appropriate, based onthe facts and circumstances ofeach area. We look forward to continuingto work with you and your staffto develop these remaining area designations for the 2006 24-hour PM2.5 NAAQS in a timely manner. Ifyou have any questions, please do not hesitate to contact me. Your air quality staffmay wishto contact Deborah Jordan, Air Division Director, at (415) 947-8715 orColleen McKaughan, Associate Air Division Director, at (520) 498-0118.Sincerely,

Laura Y shii Acting Regional Administrator Enclosure

cc: See next page

I i.e., Butte (partial), Lassen, Shasta, Sierra, Tehama, and Yuba (partial) counties. Note that nonattainment designations for the areas within Butte and Yuba counties that were previously identified in 2008 will be finalized. See Federal Register notice for final 24-hour PM2.5designations, at: www.epa.govpmdesignatiolls. 'OOhstandards!regs. hlmiiJ. 2 i.e., Lassen, Modoc, Plumas, Siskiyou, Tehama, and Trinity counties.
2cc: Linda Adams, Secretary for Environmental Protection, California EPA MaryNichols, Chairman, California Air Resources Board James Goldstene, Executive Officer, California Air Resources Board Lynn Terry, Deputy Executive Officer, California AirResources Board Karen Magliano, Chief, Air Quality Data Branch, Planning and Technical Support

Division, California AirResources Board Russ Mull, Air Pollution Control Officer, Shasta County Air Quality Management

District Gretchen Bennitt, Air Pollution Control Officer, Northern Sierra Air Quality

Management District

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