酸雨

指pH值小于5.6的雨水。其酸性来自于工业制程排放的二氧化硫（SO2）、氮氧化物（NOx）与水产生化学反应，而转化成为硫酸和硝酸。

acid rain

Rain having a pH less than 5.6. The acidity results from chemical reactions occurring when water, sulphur dioxide, and nitrogen oxides, generally released by industrial processes, are chemically transformed into sulphuric and nitric acids. (Source: DUNSTE)