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Sulfur Dioxide Pollutants

Sulfur dioxide is a chemical compound released when fossil fuels such as coal and petroleum are burned. It is also released into the atmosphere during volcanic eruptions. Although sulfur dioxide is a pollutant and is believed to have negative effects on air, soil and human health the compound does have some industrial uses.

  1. Environmental Impact

    • Sulfur dioxide is, along with nitrogen oxides, a source of acid rain. In addition to air pollution, acid rain causes soil and water pollution and accelerates the deterioration of buildings and other structures. Once in the water sulfur dioxide causes the acidification of rivers, lakes and streams which has a detrimental effect on fish and plant life in the water. It is also believed to cause mineral depletion in soil which damages vegetation in forests and other natural areas and reduces crop yields in agricultural areas.

    Health Impact

    • Sulfur dioxide in the atmosphere irritates the eyes, nose and throat. It also damages the lungs when inhaled which can have long term, negative health effects especially in individuals with conditions such as asthma. Long term exposure to sulfur dioxide can reduce lung capacity, particularly in children and may lead to other respiratory problems. At very high levels sulfur dioxide can be poisonous, but those levels are rarely encountered as a result of air pollution unless it is in an enclosed space.

    Levels and Controls

    • Since the dangers of acid rain were first realized, controls and filtering processes have been put in place to reduce sulfur dioxide in the atmosphere. This is frequently done with "scrubbers" which mix the sulfur dioxide with calcium oxide to produce calcium sulfite and prevent it from entering the atmosphere. Since 1980 the amount of sulfur dioxide found at 252 U.S. test sites has been reduced by more than 80 percent. As of 2006, China, which relies heavily on coal power and has few environmental controls, was the largest emitter of sulfur dioxide.

    Uses

    • Sulfur dioxide is commonly used in food and beverages as a preservative and antioxidant, it is especially common in winemaking and in soft drinks. A wine label with the words "contains sulfites" indicates that the wine has a concentration of 10 ppm (parts per million) or greater. Although it is generally considered safe as a few additive some individuals seem to have a greater sensitivity than others. Sulfur dioxide is also sometimes used as a reducing agent, has some medical uses and was once used as a refrigerant prior to the development of freon.

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