Acid rain is a kind of air pollution caused by chemicals in the air. Eventually these chemicals can make rain, snow, or fog more acidic than normal. The main source of these chemicals is exhaust from cars, trucks, buses, waste incinerators, factories, and some electric power plants, especially those that burn fossil fuels, such as coal.
When these chemicals mix with moisture and other particles, they create sulfuric acid and nitric acid. The wind often carries these acids many miles before they fall to the ground in rain, snow, and fog, or even as dry particles.
Acid rain can harm people, animals, and plants. It is especially harmful to lakes. Thousands of lakes in Canada, Finland, Norway, and Sweden have been declared "dead." Not even algae can live in them.
Birds and other species that depend on the lakes for food are also affected. Acid rain can also affect crops and trees. Buildings, statues, and cars are also damaged when acid rain destroys metal, stone, and paint.
