Consider the following:

  1. Carbon monoxide
  2. Nitrogen oxide
  3. Ozone
  4. Sulphur dioxide

Excess of which of the above in the environment is/are cause(s) of acid rain?


1, 2 and 3


2 and 4 only


4 only


1, 3 and 4

Correct Answer

(b) 2 and 4 only


  • The term ‘acid rain’ refers to the deposition of wet or dry acidic materials from the atmosphere on the earth’s surface.
  • The phenomenon of Acid rain was discovered in the 19th century by Robert Angus Smith, a pharmacist from Manchester (United Kingdom), who noted that there were high levels of acidity in rain falling over industrial regions of England and compared them to the much lower levels of acidity in rain falling over less polluted areas near the coast and agricultural regions.
  • The pollutants, Sulphur dioxide, nitrogen oxide which are released by burning of coal and petroleum products combine with moisture in ‘the air and rain water and produce Sulphuric acid and nitric acid respectively and fall along with the rain called as acid rain.
  • The acid rain pollute soil, water and reduces the growth of crops and fishes in river, streams, canals and ponds.
  • It also stops the growth of plants and destroys: the buildings made of marble and stones and statues made up of metals.
  • Acid rain can cause respiratory problems such as asthma, bronchitis and emphysema.
  • Sources of compounds causing acid rain:
    • Sulfur
      • Natural Resources: – Seas and oceans, Volcanic eruptions, Biological processes in the soil e.g., Decomposition of Organic matter
      • Man-made sources: – Burning of coal (60%), Petroleum products (30 % of S02) and smelting of metal sulfides ores to obtain the pure metals, Industrial production of sulphuric acid in metallurgical, chemical, and fertilizers industries.
    • Nitrogen
      • Natural Resources: – Lightning, Volcanic eruptions
      • Anthropogenic sources: – Forest fires, Combustion of Oil, Coal, And Gas