Since a chief source of pollutants is automobile emissions, it might be expected that pollutant levels could be correlated with automobile traffic, at least to some extent.

因为污染物的主要来源是汽车的排出物，所以可以料想污染物的浓度至少在某种程度上是与汽车运输有关。

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Since a chief source of pollutants is automobile emissions, it might be expected that pollutant levels could be correlated with automobile traffic, at least to some extent.

因为污染物的主要来源是汽车的排出物，所以可以料想污染物的浓度至少在某种程度上是与汽车运输有关。

youdao