When the epidemiologists examined links between particle pollution and mortality within more than 260 Los Angeles neighborhoods, they found that pollution's chronic health effects are two to three times greater than earlier believed. The study appears in the November issue of Epidemiology but was published early on the journal's Web site.

Among participants, for each increase of 10 micrograms per cubic meter (g/m3) of fine particles in the neighborhood's air, the risk of death from any cause rose by 11 to 17 percent, according to Michael Jerrett, Ph.D., associate professor of preventive medicine at the Keck School of Medicine of the University of Southern California and the paper's lead author. Fine particle levels can differ by about 20 g/m3 from the cleanest parts of Los Angeles to the most polluted.

"By looking at the effects of pollution within communities, not only did we observe pollution's influence on overall mortality, but we saw specific links between particulate matter and death from ischemic heart disease, such as heart attack, as well as lung cancers," Jerrett says. Ischemic heart disease mortality risks rose by 25 to 39 percent for the 10 g/m3increase in air pollution.

Earlier studies took one or two pollution measures from several cities and compared health effects among cities. This study digs more deeply, taking pollution measures at 23 sites within Los Angeles to more accurately reflect air pollution exposure where residents live and work.

Researchers examined data from 22,906 residents of Los Angeles, Riverside, San Bernardino and Ventura counties in the American Cancer Society's Cancer Prevention Study II since 1982. They determined air pollution exposure in
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Contact: Kathleen O'Neil
koneil@usc.edu
323-442-2830
University of Southern California
20-Sep-2005