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Study: Pollution May Cause Asthma
Illness Affects 9 Million U.S. Children

By William Booth
Washington Post Staff Writer
Friday, February 1, 2002; Page A02

LOS ANGELES, Jan. 31 -- For the first time, researchers have shown that children who breathe heavily polluted air are much more likely to develop asthma, according to a decade-long study released today.

The scientists said the study is the strongest evidence yet that smog can not only aggravate existing childhood asthma, which has reached epidemic proportions among American youth, but may actually be one cause of the life-threatening disease.

Asthma is now the leading serious chronic illness among youth, afflicting about 9 million children, and it causes not only suffering, but millions of lost hours at school and at work for parents who must nurse sick kids. Asthma sufferers feel their lungs constrict and experience, during their episodes, each new breath as if drawn through a narrow straw.

"We've known for some time that smog can trigger attacks in asthmatics. This study has shown that ozone can cause asthma as well," said Alan Lloyd, chairman of the California Environmental Protection Agency's Air Resources Board, which sponsored the newly published research conducted by the University of Southern California. The study is being published in the current issue of the Lancet, a British medical journal.

The new findings could invigorate the debate in Washington over how quickly -- and how cleanly -- America's air should be scrubbed of pollutants such as ozone, nitrogen oxides and tiny particulate dust, all produced by the machinery of the modern world, from automobiles to power plants to backyard barbecues.

The Bush administration is reviewing standards for emissions from refineries and factories and other sources, and the White House and Congress are both being heavily lobbied by industries and environmentalists.

Because of decades of stricter state and federal regulation, the air in the United States has steadily become cleaner, but in many cities, on many days, the government and health officials still consider the smog levels capable of making people sick.

Researchers said today that their finding that active children can develop asthma applies not only to the Los Angeles region, but to other heavily polluted areas, such as Washington, Houston and Las Vegas.

During a news conference announcing the study results, California officials and the researchers agreed their study suggested that even as the air has gotten cleaner, "it has not sufficiently protected children's health," Lloyd said. "We still have a long way to go."

The study compared new asthma cases in 3,535 children who were followed over five years in 12 Southern California communities, though the youths are part of a longer 10-year study. Six of the communities enjoyed relatively clean skies and six experienced some of the dirtiest air in the nation.

The researchers further focused their study on children who participated in active sports, which would require them to draw up to 17 times the "normal" amount of air sucked into the lungs of a child who was relatively inactive.

The researchers followed children who played active sports such as soccer, basketball, baseball, tennis and swimming, for at least five years, starting at age 9. They found that 265 of the children were diagnosed with asthma during the study, and that those most likely to develop the disease were exercising in the most polluted cities.

"This research suggests that contrary to conventional wisdom, ozone is involved in the causation of asthma," said Rob McConnell, associate professor of preventative medicine at the University of Southern California.

McConnell and his colleagues said they attempted to sort out other risk factors for asthma, such as a family's income, smoking habits, pest infestations and histories of allergies and other ailments.

"Somewhat to our surprise, in low-ozone communities, we found no increased risk of asthma in children who played team sports," McConnell said.

What they found was that the children who played the most active sports in the most polluted areas developed the most asthma.

"The bottom line is this: Exercise is really healthy for children, for many reasons, and children should be encouraged to play team sports," McConnell said. "But on days when air pollution levels are expected to be high, children should limit prolonged outdoor exertion."

The researchers suggested that parents in areas where the air is dirty monitor the air pollution forecasts and levels, and take appropriate action, such as stopping exercise and play.