Most fossil fuels are burned to turn into energy, and the gasses released into the air by burning, in turn causes air and water pollution. Gases released by the burning of fossil fuels include carbon monoxide, nitrogen oxides, sulfur oxides and hydrocarbons. In the air, these gases become a carcinogen, which can be inhaled and can also mix with falling rain to form acid rain.Also, burning of fossil fuels produces smoke and a lot of ash.