(November 2002)

A careful study published in the Journal of the American Medical Association in March 2002 demonstrates a clear relationship between particulate air pollution from industrial activity and deaths from lung cancer. The investigators analyzed deaths in approximately 500,000 adults who were enrolled by the American Cancer Society in 1982 and followed for the next sixteen years. The deaths by cause and geographic location were correlated with fine particle pollution measured in 51 metropolitan areas. A fine particle was defined as less than 2.5 micrometers in diameter; concentrations per cubic meter of air ranged from 5 to 20 micrograms in the 51 metropolitan areas. These fine particles are formed from combustion of fuel in cars, trucks, and various industries. A 10 microgram per cubic meter increase in fine particle concentration increased the death rate from lung cancer by 8 percent; the increased risk for lung cancer was found particularly for non-smokers whose risk of lung cancer is ordinarily very low. But, the fine particle pollution also increased mortality among current and former cigarette smokers.

The authors concluded "long-term exposure to combustion-related fine particulate air pollution is an important environmental risk factor for cardiopulmonary and lung cancer mortality".

Commentary: This is a very thorough study and it is reasonably convincing. The good news is that:

- the increased risk (8 percent overall, 16 percent going from almost no fine particulate pollution to the maximum amount observed in the 51 metropolitan areas) is small. That is especially true because the increased risk is mainly in non-smokers whose risk is very small; so, an 8 to 16 percent increase creates only a small addition to a very low risk - still, the fine particle pollution does produce a definite increase in risk of lung cancer for both smokers and non-smokers.

- the amount of fine particle pollution has been decreasing as a consequence of newer, less polluting technologies and environmental protection regulations.

There is still controversy about the health effects of fine particles and also larger particles. Some studies have shown larger particles pose health risks; others have not. This study also found risk associated with sulfur oxides pollution.

This study is persuasive enough that it would be folly to relax the regulations that require less pollution of our cities - by cars, trucks, and industrial plants. Unfortunately, the attack on environmental laws and regulations by the Bush Administration is doing just that - relaxing environmentally sound regulations, thereby endangering the health of the public.

Of course, the conclusions of this and other studies on air pollution do not change one basic irrefutable fact - the major cause of lung cancer is cigarette smoking. That risk factor dwarfs air pollution and every other risk factor for lung cancer that has ever been investigated.

Pope, C.A., et al. Lung cancer, cardiopulmonary mortality and long-term exposure to fine particulate air pollution. Journal of the American Medical Association. Vol 287 (March 6) Pgs 1132-1141. 2002.