Sulphur Dioxide gas (SO2)
Sulfur Dioxide gas is a toxic gas with a strong irritating smell. It is present at very low concentrations in the atmosphere and is naturally emitted during volcanic eruptions. Inhaling sulfur dioxide has been associated with respiratory disease and difficulty breathing. It is also a precursor to acid rain and atmospheric particulates. Sulfur dioxide gas can be an active component or a waste product of several different industrial processes.
Fossil fuel combustion at power plants is the largest emission source of sulfur dioxide into the atmosphere. Other sources include extracting metal from ore and the burning of high sulfur containing fuels by ships, trains and machinery. Perimeter monitoring at industrial sites is common to measure the concentration of sulfur dioxide being emitted into the atmosphere.
Sulfur dioxide is an intermediate component in the formation of sulfuric acid. Sulfuric acid is a very important commodity chemical used in several industrial processes including the removal of oxidation and rust from metal sheeting. Sulfur dioxide gas is also used directly in many industries. It acts as a preservative for dried fruits due to its antimicrobial properties and is used in wine making to protect the wine from spoilage.