It’s generally understood that smoking cigarettes dramatically increases one’s likelihood of developing lung cancer. But people who’ve never smoked also get lung cancer. Theories abound but there’s no generally accepted reason, other than second-hand smoke, as to why nonsmokers get lung cancer. A team of research scientists in Louisiana have just announced the discovery of a group of air pollutants, previously unknown, that is thought to be a likely culprit.

The Louisiana State University (LSU) researchers have identified a form of atmospheric free radicals that have a longer life span than other free radicals, such as those formed by a burning cigarette. These free radicals that form from burning of fuels last for less than a second and then they disappear.

The LSU team identified persistent free radicals (PFRs), so called because they linger in the air and can travel a significant distance, thereby increasing the likelihood of exposure to humans. To be in danger of the free radicals created by burning gases, exposure must be immediate, occurring in the same second of time and place the free radical exists during its very short life span. To be in danger of the PFRs, immediate and direct exposure are irrelevant.

PFRs are often metal based, with copper- and iron-based PFRs being common. The LSU research team says they are 300 times more harmful than the free radicals emitted by smoking one cigarette. The PFRs cling to nanoparticles and other very fine particulate atmospheric residue as gases cool and collect in chimneys at home, the exhaust pipes of our vehicles, and in smokestacks in industrial settings.

H. Barry Dellinger, PhD, an environmental chemist at LSU’s Baton Rouge campus, says there’s no way to ever get away from PFRs. And he fears that, since cigarettes emit PFRs as they burn, cigarette smokers are getting double the exposure to the potent effects of PFRs.

How, exactly, PFRs affect the lungs is still a mystery to Dellinger but he suspects they damage the DNA and other parts of the cell once they are inhaled and absorbed into the circulatory system. He stresses that further research is needed before definitively linking PFRs to lung cancer in nonsmokers.

Each year, an estimated 500,000 Americans die from cardiovascular diseases that are thought to originate with fine particle air pollution, including tobacco-related diseases such as lung cancer. Of this half million Americans, 10% to 15% of them are nonsmokers.

Dellinger presented his findings to the American Chemical Society earlier today as part of the society’s 236th national meeting.

Source: American Chemical Society