Acid rain is any kind of precipitation that has been contaminated due to human activities. When this precipitation is still in a cloud form, and thesmoke of cars and factories reaches it, the particles of that smoke (usually nitrogen oxide and sulfur dioxide) mix with the water vapour making the pH of the waterdecrease and become contaminated.
This means that once this contamination has reached the cloud, it would stick to the water molecules and wherever this pollutedwater goes it will affect it, as I will explain after.
How acidic is acid rain?
Acidity is measured using the pH scale. This scale goes from 0 to 14. 0 is themost acidic, therefore 14 is the most alkaline (opposite of acidic). Something with a pH value of 7 would be neutral.
Unpolluted rain would have a pH value between5 and 6, and when the air becomes more polluted water's acidity can increase to a pH value of 4, and sometimes even of 2.
What's the problem with acid rain?
Theproblem is that acid rain doesn't affect only soil for example, or water in lakes, rivers, etc. It affects everything on Earth, because plants would absorb thatwater, which is in that ground, and plants would be contaminated. The eggs of aquatic animals would be in contaminated lakes, so they could be damaged. Then, biggeranimals eat those plants and fishes, and they would also have in their organism that acid. Wen they die, as the ground absorbs dead bodies (humus), that soil willalso be affected. So acid rain, if it reaches an environment where living beings habit, it will have an influence since that moment in these living creatures life.