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This is Scientific Americans' 60-Second Science. I am Cynthia Graber. This'll just take a minute.

Air pollution is bad for our health, but scientists say we don't know much about the long-term effects. So researchers in Canada and the Netherlands decided¹ to gather genetic³ information in an urban industrial environment by looking at mouse sperm⁴. They published the study in the Proceedings⁵ of the National Academy of Sciences. The scientists placed cages of mature male mice near two steel mills and a major highway in the city of Hamilton, in Ontario, Canada. Some of the mice breathed in ambient, particulate-filled air. The control mice breathed pure, filtered air. After ten weeks, researchers checked the two groups. The mice exposed to the polluted air had a 60 percent higher rate of sperm mutation⁶. It occurred in a piece of DNA⁷ particularly susceptible⁸ to mutation. Researchers say these specific mutations are known to affect gene² expression and genome stability and could lead to changes in genetic composition and disease. They say they can't yet extrapolate from these findings to the long-term health effects in humans, but they say the results definitely warrant a more detailed⁹ look at pollution's effects on our genes¹⁰.