Newly detected air pollutant mimics damaging effects of cigarette smoke

(19 August 2008: VIDYYA MEDICAL NEWS SERVICE) -- A previously unrecognized group of air pollutants could have effects remarkably similar to harmful substances found in tobacco smoke, Louisiana scientists are reporting. Inhaling those pollutants exposes the average person up to 300 times more free radicals daily than from smoking one cigarette, they added. The discovery could help explain the long-standing medical mystery of why non-smokers develop tobacco-related diseases like lung cancer, said study leader H. Barry Dellinger.

Scientists have long known that free radicals exist in the atmosphere. These atoms, molecules, and fragments of molecules are highly reactive and damage cells in the body. Free radicals form during the burning of fuels or in photochemical processes like those that form ozone. Most of these previously identified atmospheric free radicals form as gases, exist for less than one second, and disappear. In contrast, the newly detected molecules — which Dellinger terms persistent free radicals (PFRs) — form on airborne nanoparticles and other fine particle residues as gases cool in smokestacks, automotive exhaust pipes and household chimneys. Particles that contain metals, such as copper and iron, are the most likely to persist, he said. Unlike other atmospheric free radicals, PFRs can linger in the air and travel great distances.

Once PFRs are inhaled, Dellinger suspects they are absorbed into the lungs and other tissues where they contribute to DNA and other cellular damage. Epidemiological studies suggest that more than 500,000 Americans die each year from cardiopulmonary disease linked to breathing fine particle air pollution, he says. However, Dellinger stresses additional research is necessary before scientists can definitely link airborne PFRs to these diseases. — DD

The American Chemical Society is the source of this information. The information was presented at the ACS 236th national meeting.

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