Acid rain

Acid rain is rain that is unusually acidic and highly corrosive in nature. It is rain with high levels of hydrogen ions (low pH). It may be defined as "rain water having pH less than 5.6".

Acid rain can have harmful effects on plants, animals and humans. It is caused when gaseous compounds of ammonium, carbon, nitrogen, and sulphur are released into the atmosphere. The wind carries the gases high into the sky. There the compounds react with the water in the atmosphere and acids are made. In 1852, Robert Angus Smith showed the relationship between acid rain and atmospheric pollution in Manchester.^[1] He coined the term "acid rain" in 1872.^[2]

1. ↑ Seinfeld, John H.; Pandis & Spyros N 1998. Atmospheric chemistry and physics — from air pollution to climate change. John Wiley. ISBN 978-0-471-17816-3
2. ↑ Acid rain in New England: a brief history. Epa.gov. Retrieved on 2013-02-09.