Dear Yaël and Don, 

 

I know that it's important to have clean air, but why? Besides making the air smell better, what's the advantage of reducing air pollution? 

 

Yaël: Interesting question. There are many reasons why reducing air pollution is important. For example, several studies over the past few years have linked higher levels of air pollution to putting people at greater risk for heart disease. 

 

D: But maybe the clincher is that decreasing air pollution appears to actually increase human life expectancy. A study by researchers at the University of Utah looked at air pollution statistics collected from more than sixty cities across the United States from 1979 to 1983, and then again from 1999 to 2000. The researchers also looked at life expectancy during the same periods. 

 

Y: By 2000, Americans were living an average of nearly three years longer than they had twenty years earlier. The researchers considered other factors, including fewer people smoking cigarettes, changes in income and improvements in health are. But less air pollution played an important role, too, accounting for around five months of the life expectancy increase. 

 

D: The finding is important because, as our listener's question suggests, the positive effects of cleaning the air aren't always clear. The Utah study paints a pretty clear picture: the cleaner our air, the longer we live.