acid rain

Syllable breakdown

Dictionary meaning

precipitation including rain, snow, sleet, and fog with a pH significantly lower than normal (below about 5.6) due to the dissolution of sulphur dioxide and nitrogen oxides in atmospheric water vapour, forming sulphuric and nitric acids; primarily caused by emissions from coal-burning power plants, industrial facilities, and vehicle exhausts; causes acidification of lakes and rivers killing aquatic life, leaches essential nutrients from soils damaging forests, and corrodes limestone and marble monuments and buildings; first described scientifically by Robert Angus Smith in his 1872 book Air and Rain