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Several areas in CA, AZ, NV fail to meet U.S. EPA's new health standard for ozone

Release Date: 4/15/2004
Contact Information: Laura Gentile, 415/947-4227 (

Regions required to develop plan to meet ozone standards

SAN FRANCISCO -- The U.S. Environmental Protection Agency announced today that large parts of California and two smaller areas in Nevada and Arizona are included on its list of hundreds of regions nationwide that failed to meet a new, more stringent health standard for ozone.

Today EPA administrator Mike Leavitt made a final decision that designates 474 areas of the country as out of attainment with the new eight-hour ozone, or smog, air-quality standard that is replacing a one-hour standard the agency had used since 1979.

Following is a listing of all of the areas with California, Arizona and Nevada to fail to meet the eight hour standard, along with the classification that determines how far out of compliance each area is:

California: San Francisco Bay Area (Marginal); the Sacramento region (Serious); the San Joaquin Valley (Serious); the Sutter Buttes in north Sutter County and Eastern Kern County (Basic); Western Nevada County (Basic); the central mountain counties of Amador and Calaveras (Basic); Butte County (Basic); the southern mountain counties of Tuolumne and Mariposa (Basic); the South Coast Basin, including parts of Orange, Los Angeles, Riverside and San Bernardino counties (Severe); Ventura County (Moderate); the Western Mojave Desert area, including parts of Los Angeles and San Bernardino counties (Moderate); Imperial County (Marginal); the Coachella Valley portion of Riverside County (Serious); and San Diego County (Basic).

Nevada: Clark County has been designated as Basic.

Arizona: The EPA designated the Phoenix area as Basic. The designated area is located mainly in Maricopa County as well as a small portion of northern Pinal County.

For a full description of the 8 hour standard, along with an explanation on each non-attainment designation, go to:

"Implementation of the 8 hour ozone standard will ultimately result in cleaner, safer air for millions of people living in the West," said Wayne Nastri, administrator of the EPA's Pacific Southwest Office in San Francisco. "We look forward to working with our state and local partners to advance this important, far-reaching provision of the federal Clean Air Act."

The EPA developed the new standard to protect public health from prolonged exposures to ozone. The new standard of 0.08 parts per million, which protects people from exposure to lower concentrations of ozone over the course of the day, is substantially more protective of public health than the current one hour standard. All of the areas that are out of attainment with the new 8 hour standard will be required to develop a plan to bring the area into compliance with the new EPA health standard for ozone within the next three years.

Measures that states and localities may be required to take to control ozone pollution may include stricter controls on emissions from industrial facilities, additional planning requirements for transportation sources and vehicle emissions inspection programs. The EPA plans to work with states and local governments to help develop innovative approaches to meeting the new standard. A nonattainment designation does not mean that an area must curb its growth nor does it mean the loss of highway funds -- two common myths associated with ozone designations.

Ozone is a gas that occurs naturally in the upper atmosphere to protect Earth from the sun's harmful ultraviolet rays. At ground level, ozone is created by a chemical reaction involving sunlight, high temperatures and pollutants such as car exhaust, oil and gas vapors, and paint and hairspray fumes.

Ozone pollution aggravates respiratory illnesses such as asthma, bronchitis and emphysema. Healthy people who are active outdoors on high ozone days may experience coughing, nasal congestion and itchy eyes.