The risk of dying from air pollution in parts of traffic-clogged Los Angeles appears sharply higher than previously believed, according to a study comparing the risks of living in affluent, beachfront neighborhoods to the hazy and fast-growing inland area.
LOS ANGELES The risk of dying from air pollution in parts of traffic-clogged Los Angeles appears sharply higher than previously believed, according to a study comparing the risks of living in affluent, beachfront neighborhoods to the hazy and fast-growing inland area.
The study was a first to attempt to look at how chronic health problems are linked to the degree of pollution across the neighborhoods of a major U.S. city, lead author, Michael Jerrett said.
The study, which will be published in the November issue of Epidemiology, found the risk of death rose by 11 to 17 percent from the cleanest parts of Los Angeles to the most polluted areas of Riverside and San Bernardino counties to the east.
The risk of fatal heart disease rose by between 25 percent to 39 percent as the concentration of fine particles in the neighborhood's air rose by a measure of 10 micrograms per cubic meter of air, the study showed.
Data from monitoring sites within Los Angeles show that the concentration of such airborne particles -- tiny specks of solids and droplets of acids and other chemicals -- rises by almost 20 micrograms per cubic meter as commuters head east from L.A.'s wealthier, westside neighborhoods.
Los Angeles, infamous for its smog and traffic congestion, is ringed by mountains that help trap pollution in a basin that is home to over 13 million people.
Previous research has concentrated on how the health risks from pollution differ from one city to the next, broad measurements that have been used to set air quality standards, said Jerrett, a professor at USC's Keck School of Medicine.
Scientists believe the smallest particles of pollution pose the greatest health risk since they sink deep into the lungs and enter the blood, causing inflammation and a thickening of artery walls that can prompt heart attacks and strokes.
"It's what we can't see that is most dangerous to us," Jerrett said.
The study, based on an analysis of data on almost 23,000 people tracked by the American Cancer Society, also found that the risk of death from diabetes almost doubled in the more polluted areas of Southern California.
"I think that's something we need to investigate further," Jerrett said.
A separate study by USC researchers, also published in the same medical journal, found that children living close to freeways in Southern California had a far higher risk of developing asthma. "It adds to a growing body of literature that air pollution can cause asthma," the study's lead author, James Gauderman said.
Funded by the National Institute of Environmental Health Sciences, a federal agency, the study found that children living in homes with a higher concentration of nitrogen dioxide -- a pollutant found in car exhaust -- had an 83 percent higher chance of developing asthma.
"We see that pollution is a problem from the cradle to the grave," said Jerrett.