Soot and other types of air pollution can not only affect animals and people, but developing fetuses too, researchers reported on Thursday.

They found that genetic mutations known to be caused by some pollutants can be passed through sperm to fetal mice. Presumably, the same thing could happen to human beings, they report in Friday’s issue of the journal Science.

Mice that breathed polluted air from a steel mill were much more likely to father offspring with clear genetic mutations than mice that breathed filtered air, the team at McMaster University in Toronto found.

“Our study identifies airborne particulate matter as a contributor to heritable mutation induction in mice; however, a direct link between…mutations and health effects has not yet been established,” they wrote.

“Nonetheless, structural changes in DNA have been detected in human sperm after air pollution exposure.”

Air pollution has also been linked to heart disease, lung cancer and birth defects, they noted, citing many studies.

Christopher Somers and colleagues put caged mice downwind of steel mills in Hamilton, Ontario. Some got filtered air and some got what the wind brought.

“Mice exposed to HEPA-filtered air at the urban-industrial site had paternal mutation rates that were 52 percent lower,” they wrote.

How the inhaled pollutants cause mutations is not yet clear, they said.

SOURCE: Science, May 14, 2004.