What are Sulphur Oxides?
SOx refers to all sulphur oxides, the two major ones being sulphur dioxide (SO2) and sulphur trioxide (SO3). Sulphur dioxide is a colourless gas with a pungent, irritating odour and taste. It is highly soluble in water forming weakly acidic sulphurous acid. When sulphur dioxide combines with the oxygen (O2) in the air some sulphur trioxide is slowly formed. Sulphur trioxide rapidly combines with water to produce sulphuric acid. The lifespan of sulphur oxides in the atmosphere is from 4 to 10 days. Sulphur dioxide is used in many industrial processes such as chemical preparation, refining, pulp-making and solvent extraction. Sulphur dioxide is also used in the preparation and preservation of food because it prevents bacterial growth and the browning of fruit. Sources Natural sources of sulphur dioxide include volcanoes and hot springs. Sulphur dioxide is also formed by the oxidation of hydrogen sulphide (H2S), a toxic gas that smells like rotten eggs. Oxidation occurs when hydrogen sulp
