Sulphur dioxide is a colourless gas with a pungent odour. It is an acid gas at normal temperature and is readily soluble in water and can be oxidised within airborne water droplets to form sulphuric acid.
Sources
Sulphur dioxide in the air comes mainly from activities such as the burning of coal and oil at power stations. This is the predominant source in the UK. In nature, sulphur dioxide can be released into the air by volcanic eruptions. Following the smog’s of the 1950’s and the introduction of the Clean Air Acts of 1956 and 1968, the pattern of domestic coal combustion dramatically changed with the move towards alternative, cleaner fuels. However pockets of coal burning continue within existing smoke control areas, creating localised elevations in sulphur dioxide and smoke.
Health Effects
Sulphur dioxide causes constriction of the airways when breathed in. This effect is particularly likely to occur in those already suffering breathing difficulties, including asthma and chronic lung disease.
