cars-driving-at-sunset.jpgSteps to curb air pollution in the United States are paying off, helping to dramatically increase average life spans, a new study says.

Researchers at Brigham Young University and the Harvard School of Public Health report in the Jan. 22 issue of the New England Journal of Medicine that the average life expectancy in 51 U.S. cities increased nearly three years over recent decades. (WebMD.com)