有毒有害空气污染物的环境影响是国内外研究的热点，而机动车排放是其重要源之一。

Studying the environmental effects of toxic air pollutants is currently very important in the world.

youdao

有毒有害空气污染物的环境影响是国内外研究的热点，而机动车排放是其重要源之一。

Studying the environmental effects of toxic air pollutants is currently very important in the world.

youdao