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Don: Time to go again to the A Moment of Science mailbag. A listener writes:
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 disease1.
D: But maybe the clincher is that decreasing air pollution appears to actually increase human life expectancy2. A study by researchers at the University of Utah looked at air pollution statistics3 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 improvements4 in health are. But less air pollution played an important role, too, accounting5 for around five months of the life expectancy increase.
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1 disease | |
n.疾病,弊端 | |
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2 expectancy | |
n.期望,预期,(根据概率统计求得)预期数额 | |
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3 statistics | |
n.统计,统计数字,统计学 | |
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4 improvements | |
增加或修改( improvement的名词复数 ); 改进; 改善; 改良 | |
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5 accounting | |
n.会计,会计学,借贷对照表 | |
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6 finding | |
n.发现,发现物;调查的结果 | |
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