A new study in the Journal of the American Medical Association says long-term exposure to the air pollution in some of America?s biggest cities significantly raises the risk of dying from lung cancer and is as dangerous as living with a smoker. The danger comes from combustion-related fine particulate matter, which is soot emitted by cars and trucks, coal-fired power plants and factories. This risk can be found in many big cities and even some smaller ones, according to the researchers from Brigham Young University and New York University.
In 1982, the American Cancer Society studied 500,000 adults. They examined their health records through 1998 and analyzed data on annual air pollution averages in the more than 100 cities in which they lived. Researchers also took into account other risk factors for heart and lung disease such as cigarettes, diet, weight and occupation.
Lung cancer death rates were compared with average pollution levels, as measured in micrograms per cubic meter of air. The researchers found that the number of lung cancer deaths increased 8 percent for every increase of 10 micrograms of air pollution. ?This study is compelling because it involved hundreds of thousands of people in many cities across the United States who were followed for almost two decades,? says George Thurston, an NYU environmental scientist.
Allen Dearry of the National Institute of Environmental Health Sciences, which funded the study, calls it ?the best epidemiologic evidence that we have so far that that type of exposure is associated with lung cancer death.?
Thurston says the lung cancer risks were comparable to those of nonsmokers who live with smokers and are exposed to long-term secondhand smoke. These risks have been estimated to be 16 percent to 24 percent higher than those faced by people living with nonsmokers.
The study did not list data from individual cities in which the participants lived, since it was designed to examine the overall health risk posed by fine particulate matter in the United States, not compare pollution levels in various cities. Therefore, you have no way of knowing if you?re more likely to die from lung cancer in Los Angeles than in New York. According to Thurston, the biggest sources of fine-particulate pollution are coal-burning power plants in the Midwest and East, and diesel trucks and buses in the West.
In the early 1980s, when the study began, some major cities had air pollution levels of 25 to 30 micrograms per cubic meter. In 1997, the Environmental Protection Agency set annual limits at 15 micrograms per cubic meter and tightened its standards to include fine particulate matter, which are pollutants measuring less than 2.5 micrometers (1/28th the width of a human hair).
That regulation followed another study by C. Arden Pope of Brigham Young University, which linked fine particulate pollution to lung cancer and included many of the same participants as the latest study. Industry groups challenged the earlier study and sued the EPA over the 1997 regulations, but last year the Supreme Court upheld them.
Industry challenges to the tighter standards are continuing, says Jayne Brady, of the Edison Electric Institute, which represents most of the nation?s major electric utilities, including operators of many coal-powered plants. But despite this, Brady says, ?We are trying to do everything we can to reduce emissions.?
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