Particles in the air we breathe may pose genetic risks to humans

In December 2002, associate professor of biology James Quinn and PhD student Chris Somers made headlines when they announced findings that suggested some component of industrial air pollution had the potential to cause genetic damage.

Now, joined by chemistry professor Brian McCarry, Quinn and Somers have been able to conclude that fine airborne particulate is the culprit.

"Air pollution has the potential to affect millions of humans worldwide, and has been associated with an increased risk of lung cancer and genetic damage in other tissues," says Quinn, who was the principal investigator on the study. "These findings implicate exposure to airborne particulate matter as a principal factor contributing to elevated mutation rates in sentinel mice, and add to accumulating evidence that air pollution may pose genetic risks to humans and wildlife."

In the study, published May 14 in Science, Quinn, McCarry, and Somers show that airborne particulate matter contributed to elevated mutation rates in mice. The mice were exposed outdoors to ambient air for 10 weeks at two field sites: one located in an urban-industrial area near two integrated steel mills and a major highway, and the other in a rural location 30 km away.

Comparison of genetic mutations passed from parents to offspring from each site revealed a 1.5- to 2.0-fold increase in mutation rate at the urban-industrial site, providing evidence that air pollution can cause genetic damage in germ cells, inducing trans-generational effects.

However, a second group of mice was housed inside of a high-efficiency-particulate-air (HEPA) filtration chamber. Mice exposed to HEPA-filtered air at the urban-industrial site had paternal mutation rates that were 52 per cent lower than those exposed to ambient air at the same location.

The study was funded by the Toxic Substances Research Health Initiative and the Natural Sciences and Engineering Research Council of Canada (NSERC). http://www.mcmaster.ca