酸雨

指pH值小於5.6的雨水。其酸性來自於工業製程排放的二氧化硫（SO2）、氮氧化物（NOx）與水產生化學反應，而轉化成為硫酸和硝酸。

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)