Sulfur dioxide and nitric oxides, after being emitted into the atmosphere, can be chemically converted by oxidation into sulfates and nitrates, which may return to the earth as components of rain or snow, known as acid precipitation.

• 二氧化硫和氧化氮被排放到大气中后，能氧化转变成硫酸盐和硝酸盐，这些物质可以成为雨或雪的成分并返回大地，这就是著名的酸雨。