Recent Study Shows Smog May Cause Asthma
RECENT STUDIES are confirming what health advocates have known for a long time — ozone is a serious threat to public health.
"This is a major step forward in linking the onset of asthma to air pollution."
John Balmes, MD |
A comprehensive study of children in Southern California has produced the strongest evidence yet that ozone, known as smog, can cause asthma in children. These latest findings come from the Children's Health Study, an ongoing research project funded by the California Environmental Protection Agency's Air Resources Board and conducted by the University of Southern California.
"This is a major step forward in linking the onset of asthma to air pollution," says John Balmes, MD, president of the California Thoracic Society, the American Lung Association of California's medical section. As professor of medicine at the University of California, San Francisco, and chief of the Division of Occupational Health and Environmental Medicine at San Francisco Hospital, he has spent his career studying the health effects of air pollution.
More than 3,500 children were followed over five years in 12 Southern California communities to determine the potential health damage caused by growing up in polluted air. Six of the communities had higher than average ozone concentrations while six had lower than average.
Researchers compared new asthma cases in children who played up to three team sports. Young athletes are more likely to develop asthma because participation in some sports can cause them to breathe up to 17 times the normal amount of air into their lungs.
The study showed that the children in high- ozone communities developed asthma at a rate three times higher than those in the low-ozone communities.
Previous evidence has shown that ozone can exacerbate asthma and other respiratory ailments. But this new study strongly suggests that ozone can actually cause the development of asthma in young people who previously did not have the lung disease.
Ozone Linked to Birth Defects
Another recent study conducted by the University of California, Los Angeles, links ozone to birth defects.
"Air pollution doesn't just impact asthmatics and old people at the end of life, but it can affect people at the beginning of their lives," says Beate Ritz, an epidemiologist who conducted the study, which was published in the American Journal of Epidemiology
Ritz and a team of researchers found that women exposed to high levels of ozone and carbon monoxide were three times more likely to have babies with cleft lips and palates, as well as defective heart valves.
Reducing Ozone Would Protect Public Health
Ozone is a highly reactive form of oxygen that results primarily from the action of sunlight on hydrocarbons and nitrogen oxides emitted in fuel combustion. Gasoline and diesel-powered cars, trucks and buses are major contributors to ozone air pollution.
"A major problem is the proliferation of sport utility vehicles," Dr. Balmes says. "It's ridiculous to be driving a truck to the grocery store. We need to switch over to zero emission vehicles and ultra- low emission vehicles to reduce emissions."
The American Lung Association has been working in California to reduce emissions by advocating for a steady transition to cleaner transportation by using natural gas, fuel cells and electricity. The association is also advocating for policies that would reduce emissions caused by electricity generation.
California Counties Receive Poor Marks
Ozone continues to be a serious problem in California as 33 counties received "F" grades from the American Lung Association in its State of the Air 2001 report, released last May during its Clean Air Month. The annual report card grades and ranks counties across the nation based on how often their air exceeds "unhealthful" ozone levels.
The health of more than 29 million Californians is at risk due to the high levels of ozone. While some places, like Los Angeles, have made important gains in reducing ozone levels, other areas, such as San Joaquin, are becoming smoggier.
"Los Angeles has done an admirable job of reducing ozone levels," Dr. Balmes says. "It just shows what you can do when you commit the resources and energy."
The American Lung Association will issue its State of the Air 2002 report in May. The complete report, including county-by-county results, will be available online at www.californialung.org.
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