Acid Rain Acid rain is polluted rain. The pollutants go up to the atmosphere and when it rains it brings the pollution down with it. Sulfur dioxide and nitrogen oxide are the gases that form the acid rain. When these gases mix with moisture it can make rain, snow, hail, or even fog. The scientific term for acid rain is acid deposition which means when the acid is taken from the air and is deposited on the earth. Major industries, coal burning factories, power plants and automoble engines are the main sources of sulfur dioxide and nitrogen oxide which caues acid rain. Volcaneoes and forest fires also causes sulfur dioxid