About

• Sulphur dioxide (SO2) is a gaseous air pollutant composed of sulfur and oxygen.
• SO2 is a colourless, soluble gas with a characteristic pungent smell which forms sulphuric acid when combined with water.
• Sulphur dioxide Emissions: 
  • Anthropogenic sources of sulphur emissions include, burning of coal in power plants, oil refineries, motor vehicles , domestic boilers, etc.
  • Natural sources for the emission of Sulphur dioxides include volcanic eruptions, forest fires, etc.

• SO2 emissions can cause respiratory, cardiovascular and lung diseases, and can induce acid rain, which is a threat to crops, forests, and aquatic species.

Role of SO2 in cooling the planet

• SO2 emissions cool the planet in two ways:
  • First is the direct effect, in which SO2 in the atmosphere is converted into sulphate aerosols that reflect solar radiation into space. 
  • The second, indirect effect is brought about by the interaction between clouds and sulphate aerosols. Clouds formed around sulphate aerosols have more droplets, and are brighter and more reflective of sunlight than normal clouds.