Exhaust Fumes Impact Mortality Rates From Heart, Lung Disease

Mortality rates for California residents increase when levels of microscopic, tailpipe exhaust particles are elevated, according to a study published in the journal Environmental Health Perspectives, the Sacramento Bee reports. The higher mortality rate is generally limited to people with heart or lung disease, the researchers said.

Bart Ostro, the state's top air pollution epidemiologist, and scientists at the University of California-Davis and UC-San Francisco studied four years of air pollution data taken from monitors in Contra Costa, Fresno, Kern, Los Angeles, Orange, Riverside, Sacramento, San Diego and Santa Clara counties. The study also considered mortality data for the same time period from the Department of Health Services.

A particularly "significant association" between microscopic particles and mortality was found in the southern San Joaquin Valley and in Riverside and San Bernardino counties, the Bee reports.

For reasons not determined, the increase in the death rate from lung diseases in Sacramento County was more than twice the increase in any other area besides Orange County. Researchers said a possible explanation was a difference in the chemical composition of particles in different areas.

In addition, the link is especially apparent among women, diabetics and people over age 65. The study also found higher mortality rates among people with less than a high school education.

In their paper, the scientists stated, "Overall, this large, multicounty analysis provides evidence of significant associations of fine particles with daily mortality among nearly two-thirds of California's population."

Ostro has launched a follow-up study to determine which factors cause mortality rates to differ from place to place (Bowman, Sacramento Bee, 9/26).