- 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.

“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, Dellinger said.

Studies have shown that more than 500,000 Americans die of
cardiopulmonary disease linked to breathing fine air particle pollution
every year. Some 10 percent to 15 percent of lung cancers occur in
nonsmokers and have been linked to air pollution, according to the
American Cancer Society.

It's possible that persistent free radicals are the real culprit in
these deaths, Dellinger said.

Dr. Neil Schachter, a professor of pulmonary medicine at Mount Sinai
Medical Center in New York City, thinks it's premature to blame persistent
free radicals for the adverse effects of air pollution.

“These airborne free radicals are of interest, but I am not sure we are
at a point where our scalpel is sharp enough to dissect the individual
components of air pollution that cause problems for people,” he said.

It's possible that persistent free radicals are responsible for the
respiratory damage caused by pollution, Schachter acknowledged. “There are
studies that show that modifying free radicals can alter the course of
disease,” he said. “But the implications of this — what it means to
clinics, what it means to doctors, what it means to regulators — I think
we are a long way from pulling that together.”

More information

For more on the health risks posed by air pollution, visit the U.S.
Centers for Disease Control and Prevention.