Where does Sulfur Oxides Come From?
Sulfur oxides are present naturally at low concentrations in Earth’s atmosphere, and at much higher concentrations in polluted urban environments. Natural sources include volcanoes, sea spray, biological decay, and forest fires. Fossil fuel combustion accounts for 75 to 80% of human production of sulfur oxides in the air. Coal burning generates about half of the sulfur oxide emissions we release, while burning oil accounts for 25 to 30%. Smelting, manufacture of sulfuric acid, conversion of wood pulp to paper, and incineration of refuse are other man made sources of atmospheric sulfur oxides.
