Winston H. Hickox

Agency Secretary

The energy challenge facing California is real. Every Californian needs to take immediate action to reduce energy consumption.

For a list of simple ways you can reduce demand and cut your energy costs, see our Website: http://www.arb.ca.gov.

California Environmental Protection Agency

Air Resources Board

Alan C. Lloyd, Ph.D.

Chairman

1001 I Street • P.O. Box 2815 • Sacramento, California 95812 • www.arb.ca.gov

Gray Davis

Governor

July 15, 2003

Mr. Jack Broadbent, Director

Air Division - Region IX

U.S. Environmental Protection Agency

75 Hawthorne Street

San Francisco, California 94105

Dear Mr. Broadbent:

We are transmitting California’s eight-hour ozone monitoring data for 2000 through 2002

to support the U.S. Environmental Protection Agency’s (U.S. EPA) steps to designate

areas as attainment or nonattainment for the federal eight-hour ozone standard.

This information updates California’s March 2000 recommendations on designations

and boundaries due to changes in air quality status during the monitoring period. Three

areas now attain the eight-hour standard (San Francisco Bay Area, Shasta County, and

Tehama County) and one additional area now violates the standard (Butte County).

Enclosure 1 shows that fourteen areas in California currently violate the standard based

on 2000–02 monitoring data. Eleven of these areas are already nonattainment or

maintenance for the federal one-hour ozone standard. The remaining rural areas are

impacted by transport from upwind urban regions and will be brought into the federal

planning process for the first time.

California has widespread ozone pollution resulting from both local sources and winds

that blow emissions from urban coastal areas, through the Central Valley, into the Sierra

Nevada foothills, and across the eastern desert. There are numerous routes of

pollutant transport between the fourteen areas that violate the standard, as well as the

San Francisco Bay Area. Thus, the State Implementation Plans (SIP) to attain the

eight-hour ozone standard must and will include emission reductions from the

contributing upwind districts.

We are in the process of working with the Bay Area Air Quality Management District and

its downwind neighbors on a legally enforceable mechanism for addressing this issue.

We believe State law provides a sound legal foundation for incorporating upwind

emission reductions in downwind area SIPs.
Mr. Jack Broadbent, Director

July 15, 2003

Page 2

The federal Clean Air Act generally delegates responsibility to each state to ensure that

the comprehensive SIP reduces air pollution to attainment levels for all areas inside its

borders. This responsibility encompasses pollution generated in upwind regions that

contributes to nonattainment in downwind regions within the same state. California law

goes further and clearly imposes an obligation on upwind air districts to mitigate air

pollutant transport. ARB is responsible for ensuring this mitigation happens under both

federal and State law. Recent revisions to state transport mitigation regulations compel

an upwind district to take expeditious action to reduce emissions until the downwind

area attains California’s health-protective ozone standard. The requirements on upwind

districts also include the adoption of all feasible measures and parity with the downwind

area’s program to address new and modified stationary sources. ARB is committed to

ensuring effective implementation of these requirements and to reflecting the resulting

benefits in the SIPs for downwind areas. Air Resources Board Members and staff are

currently working with local air district representatives to craft an effective inter-regional

planning strategy for California’s eight-hour ozone SIPs.

Our prior recommendations for nonattainment areas considered air basin boundaries,

geography and meteorology, the location of emission sources, transportation corridors,

metropolitan areas, and existing political jurisdictions. We will transmit specific

descriptions of the recommended nonattainment area boundaries in supplemental

correspondence, before U.S. EPA proposes nationwide designations this fall. An

outstanding issue is the Sacramento Region boundary, specifically treatment of

Southern Sutter County that is now part of the one-hour ozone nonattainment area.

Enclosure 2 provides summary eight-hour ozone data for all California monitoring sites

from 2000 through 2002. We will update the air quality data and any changes to our

recommendations, based on monitoring during the 2003 ozone season and

consideration of the implementation policy, before U.S. EPA finalizes the designations.

If you have any questions, please call Ms. Lynn Terry, Deputy Executive Officer, at

(916) 322-2739 or have your staff contact Ms. Cynthia Marvin, Chief, Air Quality and

Transportation Planning Branch, at (916) 322-7236.

Sincerely,

Catherine Witherspoon

Executive Officer

Enclosures

cc: See next page.
Mr. Jack Broadbent, Director

July 15, 2003

Page 3

cc: (With Enclosures 1 and 2)

Air Pollution Control Officers

Directors of Metropolitan Planning Organizations

Mr. Brian Smith, Deputy Director

Planning and Modal Programs

California Department of Transportation

1120 N Street

Sacramento, California 95812

Ms. Lynn Terry

Air Resources Board

Ms. Cynthia Marvin

Air Resources Board
Enclosure 1

Areas in California that Violate the Federal Eight-Hour Ozone Standard

 (based on 2000 – 2002 air quality data)

Area Design Value1

(ppm) Includes

South Coast Air Basin 0.128 Western Los Angeles (including

Catalina and San Clemente Islands),

Orange, Southwestern San Bernardino,

and Western Riverside Counties

San Joaquin Valley 0.115 San Joaquin, Stanislaus, Merced,

Madera, Fresno, Kings, Tulare, and

Western Kern Counties

Sacramento Region 0.106 Sacramento, Yolo, Eastern Solano,

western portions of El Dorado and

Placer County (inclusion of Southern

Sutter County to be determined)

Western Mojave Desert 0.106 Central San Bernardino County

Coachella Valley 0.105 Central Riverside County

Ventura County 0.097 Continental portion of Ventura County

(excludes Anacapa and San Nicolas

Islands)

Eastern Kern County 0.095 Portion of Kern County east of the

Tehachapi Mountains except the Indian

Wells Valley

San Diego County 0.095 San Diego County

Antelope Valley 0.0912 Northeastern Los Angeles County

Imperial County 0.090 Imperial County

Western Nevada

County

0.098 Portion of Nevada County west of the

crest of the Sierra Nevada

Central Mountain

Counties

0.092 Amador and Calaveras Counties

Southern Mountain

Counties

0.091 Tuolumne and Mariposa Counties

Butte County 0.089 Butte County

1

The design value is the three-year average of the annual fourth highest eight-hour ozone

concentration at the highest monitor (if less than 0.085 = attainment, if 0.085 ppm or greater =

nonattainment)

2

Preliminary design value is based on air quality data from 1999 – 2001. Since the monitor was

moved in 2001, a final design value cannot be calculated until complete data for the 2003 ozone

season are available.

July 15, 2003