Newly Discovered Air Pollutants May Cause Lung Problems

MONDAY, Aug. 18 (HealthDay News) -- Recently discovered so-called free radicals that are attached to small particles of air pollution could cause lung damage and perhaps even lung cancer, researchers report.

If confirmed through further research, the finding could help to explain why nonsmokers develop tobacco-related diseases like lung cancer, said lead researcher H. Barry Dellinger, the Patrick F. Taylor Chair of environmental chemistry at Louisiana State University.

It has been known for years that free radicals exist in the atmosphere, and these atoms, molecules and fragments of molecules can damage cells. It had been thought that these particles, which can be produced by combustion, exist for less than a second and then disappear.

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"What I found out is that combustion-generated particles contain environmentally persistent free radicals," said Dellinger. "When the radicals are associated with particles, they can apparently exist indefinitely."

These free radicals are remarkably similar to the free radicals found in cigarette tar, Dellinger said. "The implication is you can have the same environmentally related diseases by exposure to airborne fine particles that you can get from cigarettes," he said.

Dellinger noted, however, that one would have to smoke about 300 cigarettes a day to be exposed to the same level of environmental free radicals found in moderately polluted air.

The findings were to be presented Monday at the American Chemical Society annual meeting, in Philadelphia.

The persistent free radicals (PFRs) discovered by Dellinger's team attach themselves to small particles of air pollution as they leave smokestacks, car exhaust pipes and household chimneys, and continue to exist as free radicals. Particles of air pollution containing metals, such as copper and iron, are more likely to remain in the atmosphere and can carry these PFRs great distances, Dellinger said.

As PFRs are inhaled, they're absorbed by the lungs and other tissues and cause cell damage that can lead to problems such as asthma, emphysema and lung cancer. However, there's still no direct evidence linking PFRs to any of these diseases, he said.