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U.S. EPA approves State of California’s request to redesignate the San Joaquin Valley Air Basin to attainment EPA also approves commitment for monitoring in East Kern area

Release Date: 09/24/2008
Contact Information: Mary Simms, (415) 947-4270,

(9/25/2008 -- SAN FRANCISCO) The U.S. Environmental Protection Agency has redesignated the San Joaquin Valley air basin to attainment for the national ambient air quality standard for coarse particulate matter (PM-10) – also approving the PM-10 maintenance plan for the area.

In doing so, the EPA first approved the state’s request to change the boundary of the San Joaquin Valley nonattainment area by splitting the area into two separate PM-10 nonattainment areas.

Geographically, the area will now be divided into the San Joaquin Valley air basin PM-10 area, and the East Kern PM-10 area. This change reflects natural geographical and jurisdictional divisions for these two distinct air basins. With this split, PM-10 now follows the same regulatory boundaries as PM-2.5 and ozone for the SJV air basin.

East Kern will continue to be a PM-10 nonattainment area. The EPA is approving a commitment from the state to install a PM-10 monitor in East Kern that will address Clean Air Act requirements for the area.

“The EPA remains committed to the emission controls, enforcement and monitoring requirements currently in place in the San Joaquin Valley,” said Deborah Jordan, Air Division director for the U.S. EPA’s Pacific Southwest region. “In addition to the current controls, many additional reductions will be needed to attain the more protective PM 2.5 standard and the ozone standard.”

The maintenance plan retains all PM-10 controls and monitoring for the SJV air basin, provides a demonstration that the area will continue to attain until 2020, and provides for contingency measures if the area does not continue to attain.

Particulate matter (PM) pollution is a complex mixture of extremely small particles and liquid droplets. It’s made up of a number of components, including acids, organic chemicals, metals, and soil or dust particles.

The size of particles is directly linked to their potential for causing health problems. The EPA is concerned about particles 10 micrometers in diameter or smaller because those are the particles that generally pass through the throat and nose and enter the lungs. Once inhaled, these particles can affect the heart and lungs and cause serious health effects.

Areas of the country where air pollution levels persistently exceed the national ambient air quality standards (NAAQS) may be designated "nonattainment." To view a list of areas designated nonattainment please visit: