Air Pollution

Air Pollution

  • The following are the major gaseous and particulate pollutants present:
    • Gaseous air pollutants: Oxides of sulphur, nitrogen and carbon, hydrogen sulphide, hydrocarbons, ozone and other oxidants.
    • Particulate pollutants: Dust, mist, fumes, smoke, smog etc. In India, thermal power plant account for 80% of all industrial emissions of particulate matter, sulphur and nitrous oxides in India.


Sulphur Dioxide Pollution

  • Oxides of sulphur are produced when sulphur containing fossil fuel is burnt.
  • Most common oxide of sulphur is sulphur dioxide, SO2.
  • Sulfur dioxide is a gas. It is invisible and has a nasty, sharp smell. It reacts easily with other substances to form harmful compounds, such as sulfuric acid, sulfurous acid and sulfate particles.
  • Particulate matter in the air accelerates formation of oxides of sulphur catalyses the process of oxidation.



Sources of SO2 Pollution

  • Burning of fossil fuels such as coal, oil and natural gas are the main source of SO2 emissions.
  • Volcanic eruptions are also a major source of SO2 emissions.
  • Hydrogen sulphide, released from biological decay, reacts with O2 in the atmosphere to produce SO2.


Harmful effects of SO2

  • SO2 is a poisonous gas known to cause respiratory diseases such as asthma, bronchitis, emphysema in human beings, irritation to the eyes.
  • At high concentrations, gaseous SOx can harm trees and plants by damaging foliage and decreasing growth.
  • SO2and other sulfur oxides can contribute to acid rain which can harm sensitive ecosystems.
  • SO2and other sulfur oxides can react with other compounds in the atmosphere to form fine particles that reduce visibility.
  • Deposition of particles can also stain and damage stone and other materials, including culturally important objects such as statues and monuments. SO2 is the main cause of discoloration of marble in Taj mahal.

Section : Environment & Ecology