【英语时差8,16】空气污染更容易引起心脏病

A study finds that air pollution is worse for the heart than the lungs.The American Heart Association published the findings in its magazine, Circulation¹. Researchers used information given by more than half-a-million adults. The information is from a continuing study by the American Cancer Society on cancer prevention. The study included people thirty and older living in cities where officials kept records on air pollution. During the sixteen-year period, one in five of the people in the study died. The scientists found that heart disease caused about forty-five percent of the deaths. Only eight percent of the people died from diseases of the breathing system. The researchers compared the information with air pollution records from more than one-hundred-fifty cities. The scientists controlled for things that increase the risk of heart disease, like smoking and being overweight. Still, they found a stronger link between air pollution and heart disease than respiratory disease.

1 circulation   

n.循环，流通，传播，发行，发行量

参考例句：

• There is a large circulation in the musical public.在音乐界销路很广。
• The ideas have been in circulation for some time.这些想法已经流行了一段时间。