Acid rain is rain that is more acidic than normal.
Acid rain is a complicated problem. Caused by air pollution, acid rain's spread and damage involves weather, chemistry, soil, and the life cycles of plants and animals on the land and from acid rain in the water. Acid rain causes acidification of lakes and streams and contributes to damage of trees at high elevations. In addition, acid rain accelerates the decay of building materials and paints, including irreplaceable buildings, statues,and sculptures that are part of our nation's cultural heritage. Air toxics are known or suspected to cause cancer or other serious heath effects, such as damage to respiratory or nervous systems.