pollutant levels meaning in English

污染物浓度

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。
If the water is not adequately circulated and used then pollutant levels would increase
假如海水没有得到适当的循环及使用，便可能会增加污染物的数量。