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San Joaquin Valley continues to meet federal coarse particle standard: No PM-10 regulatory violations for 4 year period

Release Date: 03/10/2008
Contact Information: Mary Simms 415-947-4270

SAN FRANCISCO – The U.S. Environmental Protection Agency is affirming that the San Joaquin Valley has attained the PM-10 air quality standard, relating to coarse particle pollution. This final action concurs with the State of California and the Santa Rose Rancheria’s request to “flag” certain PM-10 exceedances and therefore exclude them from regulatory consideration.

Air monitors throughout the Valley reported no regulatory violations of the PM-10 standard from 2003 through the end of 2006.

"The Valley continues to move toward cleaner air", said Deborah Jordan, the Air Division director for EPA's Pacific Southwest region. "There is still more work needed to reduce smog and fine particle pollution, but meeting the federal coarse PM standard is a step in the right direction".

The EPA considered public comments, both in favor, and against excluding several of the 2006 exceedences. Exceedances on six days were recorded in the fall of 2006. Three exceedence days were attributed to high wind events. Three exceedence days occurred due to improperly sited air monitors during construction activity. Due to the nature and cause of these exceedences and the documentation provided by the State, EPA excluded them from regulatory consideration as allowed for by the Clean Air Act.

Air monitoring data for the Valley is reported to the EPA from the Air Resources Board and the San Joaquin Valley Air District’s official air monitoring network. The network consists of 15 monitoring sites from Stockton to Bakersfield, operated in accordance with EPA regulations and guidelines to ensure precision and accuracy.

The State of California has submitted a PM-10 maintenance plan and request for redesignation to attainment -- the EPA is currently reviewing that request. Today’s action does not redesignate the San Joaquin Valley to attainment for the PM-10 standard.

Particle pollution is a complex mixture of extremely small particles and liquid droplets in the air. When inhaled, these particles can reach the deepest regions of the lungs. Exposure to particle pollution is linked to a variety of significant health problems, ranging from aggravated asthma to premature death in people with heart and lung disease. It’s also the main cause of visibility impairment in the nation’s cities and national parks.

Relevant information, including a fact sheet will soon be posted on:

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