Thermal pollution is pollution caused by the heat energy discharged from modern industrial production and other human activities. Hot water discharged from the cooling systems of thermal power plants, nuclear power plants, coal-fired power plants, and iron and steel plants as well as the production waste discharged from factories, such as petroleum, chemical and papermaking facilities, contains large amounts of waste heat. Additional energy is released from households and vehicle exhaust heat. Heat pollution can pollute the atmosphere and water bodies. The waste heat energy increases the air and water temperatures, leading to changes in the ecological environment.