The number of deaths from breathing sooty smog in California may be more than twice as high as previously estimated, based on a recent USC study that examined the risk of such deaths in the Los Angeles Basin.
A team of researchers headed by Michael Jerrett, associate professor of preventive medicine, found two to three times greater risk of mortality from heart attacks, lung cancer and other serious illness tied to chronic exposure to fine particulate matter than did previous studies.
The study looked at specific soot measurements and deaths in hundreds of neighborhoods -- rather than relying on citywide annual averages used in the past -- and detected the largest increased risks in the Inland Empire, Jerrett said.
Fine particulate matter spewed out by cars, trucks, locomotives, ships, planes, refineries and other sources lodges deep in the lungs and is widely considered the most lethal form of air pollution.
The staff of the California Air Resources Board said this week they are considering boosting statewide death estimates based on the USC data, pending independent review.
"I think candidly it's likely," said Michael Scheible, deputy executive director of the board. "The research suggests we will end up raising our estimates ... but we want to be cautious."
Currently, state officials estimate 9,000 Californians die annually from diseases caused or aggravated by air pollution, more than half of them in Southern California.
That number could double or even triple if the Air Resources Board incorporates the USC data into its estimates, Scheible said.
He said the board decided Thursday that the USC study and two others examining the effect of air pollution on mortality should undergo one more layer of review to determine the best possible way of applying them statewide. That review could be completed by the end of summer.
The other studies include one by researchers at Harvard University who found that as soot pollution declined in six northeastern cities, related deaths declined as well. The other, a recent study by Loma Linda University, found increased coronary deaths among women exposed to both fine particulate matter and ozone.
The Times reported earlier this week that one in every 15,000 Californians -- about 66 per million -- is at risk of contracting cancer from breathing chemicals in the air over his or her lifetime, according to the U.S. Environmental Protection Agency's recent National-Scale Air Toxics Assessment. The study was based on emissions of 177 chemicals in 1999.
