“这些微细颗粒物是影响可见度，让天空看起来雾茫茫的原因，”康奈尔空气质量专家威斯·特达说，“它也是最直接影响健康的因素。”

"The fine particulate matter is what affects visibility and makes it look like a horrible foggy day," said Cornell air quality expert Westerdahl. "it also is what most directly affects human health."

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并对影响城市空气质量的5个主要因素进行主成分分析，找出最能代表原来数据信息的2至3个因子代替原来的5个变量。

Then 5 main factors affecting urban air quality to principal component analysis identify the most representative of the original data instead of the 2 to 3 factors 5 variables.

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摘要：本文针对我国城市的空气质量现状及影响城市空气质量的主要因素进行分析研究。

Abstract: This article mainly analyze urban air quality present situation in China and the key factors affecting urban air quality study.

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