Know how to use "fewer" and "less"? Find out.
|acid precipitation |
Any form of precipitation, including rain, snow, hail, fog, or dew, that is high in acid pollutants, especially sulfuric and nitric acid. Acid precipitation has a pH of less than 5.6 (the normal acidity of unpolluted atmospheric water) and is often less than pH 5.0. Also called acid rain. See Note at acid deposition.