Part of the problem starts with us. The fuels we burn to make electricity and run cars release sulfur dioxide and nitrogen oxide into the air. These gases mix with water and oxygen already in the air to make acids such as sulfuric acid. Some of the acids fall to earth as acid rain or snow. Some fall as dry particles. The rest stays in the air,and we breathe it. Acid deposits that fall to earth run off into lakes and streams. If the soil under the water cannot neutralize the acid, the water itself becomes more and more acidic.