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U.S. EPA Finds San Diego County Meets Federal Fine Particulate Standard

Release Date: 4/5/2005
Contact Information: Francisco Arcaute, (213) 244-1815, Cell: (213) 798-1404, Main press line: (415) 947-8700

SAN FRANCISCO - The U.S. Environmental Protection Agency today announced that San Diego County, Calif., attains the federal standard for fine particulates, which are solid particles and liquid droplets found in the air that cause respiratory and cardiovascular illness. This designation is based on San Diego area air monitoring data for the years 2002 - 2004.

"The EPA is pleased to acknowledge the trend toward improved air quality in the San Diego area," said Deborah Jordan, director of air programs for EPA's Pacific Southwest regional office. "Attainment of the fine particulate standard demonstrates continued effort by the private and public sectors to ensure a healthier environment for San Diego."

In December 2004, the U.S. EPA announced that San Diego County did not attain the standard for fine particulates, based on 2001 - 2003 data. The EPA revised its designation when newer monitoring data showed that the county met the fine particulate standard. Presently, only two areas in California are designated by the EPA as failing to meet the federal standard for fine particulates: the South Coast (Los Angeles area) Air Basin and the San Joaquin Valley.

PM2.5 is made up of very fine particles of sulfates, nitrates and carbon compounds that can lodge deeply into the lungs causing a myriad of respiratory health problems. The particles can be emitted directly from smoke or fire or can form from certain chemical reactions in the air. Those chemicals come from a variety of sources, including cars, trucks, buses, construction equipment, industrial facilities and power plants.

PM2.5 can be present all year. Unlike ozone, there is no consistent nationwide "season" for particle pollution and PM levels can be elevated year-round. In California, PM2.5 tends to be higher in the fall and winter because nitrates form better in cooler weather and increased use of wood stoves and fireplaces produces more carbon.

A recent EPA report demonstrated that the country has made progress in reducing fine and coarse particle pollution from 1999 to 2003. In 2003, fine particle concentrations were the lowest they have been since nationwide monitoring began in 1999.

During this period, concentrations dropped the most in areas with the highest concentrations. For example, PM2.5 concentrations fell by 16 percent in Southern California.

For more information, please visit https://www.epa.gov/region09/air/sandiegopm25 .