air pollution

There are many sources of air pollution; exhaust fumes, for example.

空气有许多来源, 例如废气。

California's air pollution guidelines are stringent.

加州制定空气标准很严格。

Air pollution in the city had reached four times the acceptable levels.

这座城市空气程度曾高达可接受标准四倍。

Setting off firecrackers makes a tremendous noise and causes serious air pollution.

燃放鞭炮会产生巨大噪声,严重大气。

This article summarized the indicating function of bryop hyte to air pollution, heavy metal pollution and mineral resources.

综述了苔藓植物对大气、重金属和监测指示作用。