What is acid rain ?

What is acid rain ?
Acid rain is rain that is unusually acidic, (low pH). It can have
harmful effects on plants, aquatic animals, and infrastructure through
the process of wet deposition.
Acid rain can be caused naturally by lightning
strikes and volcano eruptions, or by polluting emissions of
compounds of ammonium, carbon, nitrogen,
and sulfur
which react with the water molecules in the atmosphere to produce acids.

2010-04-13 16:44:05 補充：
Acid rain is rain that is unusually acidic, (low pH). It can have harmful effects on plants, aquatic animals, and infrastructure through the process of wet deposition.

2010-04-13 16:44:12 補充：
Acid rain can be caused naturally by lightning strikes and volcano eruptions, or by polluting emissions of compounds of ammonium, carbon, nitrogen, and sulfur which react with the water molecules in the atmosphere to produce acids.

The rain containing less than pH 5.7 is called acid rain. It is usually caused by sulphur dioxide in air pollution, produced by factories in common.