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Area Designations for 2008 Ground-level Ozone Standards

2008 Ground-level Ozone Standards —
Region 9 Final Designations, April 2012

EPA is implementing the 2008 ozone standards as required by the Clean Air Act.  Meeting these standards will provide important public and environmental health benefits. EPA has worked closely with states and tribes to identify areas in the country that meet the standards and those that need to take steps to reduce ozone pollution.

EPAs final designations are based on air quality monitoring data, recommendations submitted by the states and tribes, and other technical information. EPA will work closely with states and tribes to implement the standards using a common sense approach that improves air quality, maximizes flexibilities and minimizes burden on state and local governments.

Map of Final Designations - EPA Region 9

Region 9

This table identifies area designations for EPAs region 9 states. In some cases EPA designated partial counties. These are identified by a (P). If a county is not listed below, EPA has designated it as unclassifiable/attainment.

EPA Areas for Designations for the 2008 Ozone Standards

State Area Name Counties Area Classification
American Samoa Entire territory is unclassifiable/attainment
Arizona Phoenix-Mesa, AZ Maricopa (p) Marginal
Pinal (p)
Rest of state is unclassifiable/attainment
California Calaveras County, CA Calaveras Marginal
Chico (Butte County), CA Butte Marginal
Imperial County, CA Imperial Marginal
Kern County (Eastern Kern), CA Kern (p) Marginal
Los Angeles-San Bernardino Counties (West Mojave Desert), CA Los Angeles (p) Severe
San Bernardino (p)
Los Angeles-South Coast Air Basin, CA Los Angeles (p) Extreme
Riverside (p)
San Bernardino (p)
Mariposa County, CA Mariposa Marginal
Nevada County (Western part), CA Nevada (p) Marginal
Riverside County (Coachella Valley), CA Riverside (p) Severe
Sacramento Metro, CA El Dorado (p) Severe
Placer (p)
Solano (p)
Sutter (p)
San Diego County, CA San Diego Marginal
San Francisco Bay Area, CA Alameda Marginal
Contra Costa
San Francisco
San Mateo
Santa Clara
Solano (p)
Sonoma (p)
San Joaquin Valley, CA Fresno Extreme
Kern (p)
San Joaquin
San Luis Obispo (Eastern San Luis Obispo), CA San Luis Obispo (p) Marginal
Tuscan Buttes, CA Tehama (p) Marginal
Ventura County, CA Ventura (p) Serious
Morongo Areas of Indian Country (Morongo Band of Mission Indians) Areas of Indian Country Serious
Pechanga Areas of Indian Country (Pechanga Band of Luiseno Mission Indians of the Pechanga Reservation) Areas of Indian Country Moderate
Rest of state is unclassifiable/attainment
Guam Entire territory is unclassifiable/attainment
Hawaii Entire state is unclassifiable/attainment
Nevada Entire state is unclassifiable/attainment
Northern Mariana Islands Entire territory is unclassifiable/attainment

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Tribal information is available on the Tribal Designations page.

Recommendations from Region 9 States and EPA Responses


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