Coal itself is a heavy pollutant.

煤本身就是一种严重的污染物。

youdao

The treatment method is environment friendly, does not generate pollutant gas or heavy metal ions;

环保型，不产生污染气体和重金属离子；

youdao

The treatment method is environment friendly, does not generate pollutant gas or heavy metal ions;

环保型，不产生污染气体和重金属离子；

youdao