Atmospheric sulfur dioxide that dissolves in it on its way down.
It is fairly common in some countries that air pollution causes acid rain.
Because rainwater is mildly acidic. Acid in the rainwater dissolves the limestone.
because it does not contain acid
Rain water is generally acidic
That depends where you live. Acidic rainwater is not always better than groundwater.
Erosion I think :-)
Yes it can
Rainwater is normally acidic because the carbon dioxide in the air which mixes with rainwater to form weak acid. That's why its acidic ^_^ Rainwater is also because of the pollutions in the air and it mixes with the water so its not good. meee!
salt salt makes it more acidic
Could be either, although it's essentially rainwater, which is normally acidic.
Quickly evaporating rainwater causes most of the drought cycles
The rainwater is more acidic after passing through polluted air.