Gaseous Pollutants

Concept Explanation

Gaseous Pollutants

Gaseous air pollutants are emitted from various natural sources, such as volcanoes and forest fires. However, human generated emissions of some gases may be greater than the natural ones, and are increasing because of population growth and industrialization.

Air Pollutants, Their Sources and Their Effects. The major air pollutants are:

Gaseous Pollutants: These are the pollutants which remain in gaseous state at normal temperature and pressure. For example, carbon monoxide, carbon dioxide, oxides of nitrogen, sulphur dioxide.

  • Carbon monoxide (CO): Carbon monoxide gas is the main air pollutant. It is very poisonous. It lowers the amount of oxygen that enters our blood. It can slow down our reflexes.
  • Carbon dioxide (CO_2) : Accumulation of excessive carbon dioxide traps large amount of heat and increases the earth’s temperature. This is called the greenhouse effect.
  • Sulphur dioxide (SO_2) : Sulphur dioxide is a serious health hazard. Sulphur dioxide is so poisonous that it can damage our lungs by causing diseases like bronchitis. It also damages the plants by causing their leaves to dry up and fall off. It combines with the oxygen of the air and form sulphur trioxide (SO_3). This reacts water present in the clouds to form sulphuric acid (H_2SO_4). Rain mixed with sulphuric acid is called acid rain.
  • Nitrogen dioxide (NO_2) : Nitrogen dioxide is poisonous. It irritates the eyes. Like SO_2, it damages our lungs and can cause breathing problems. The exhausts of vehicles, and some industries release this gas. Nitrogen dioxide reduce oxygen present in the air and form nitrogen trioxide (NO_3). Nitrogen trioxide so formed combines water vapour present in the air to form nitric acid (HNO_3). Nitric acid dissolves in rain water and reaches the earth in the form of acid rain.
  • Sample Questions
    (More Questions for each concept available in Login)
    Question : 1

    Which of the following gas causes harm to plants by causing their leaves to dry up and fall off ?

    Right Option : A
    View Explanation
    Question : 2

    Match column I with column II and select the correct option from the codes given below.

    Column IColumn II

    (A) Carbon monoxide

    (B) Inert gas

    (C) Sulphur dioxide

    (D) Nitrogen

    (p) Poisonous gas

    (q) Inactive gas

    (r) Causes respiratory problems

    (s) Xenon


    Right Option : A
    View Explanation
    Question : 3

    Bhopal tragedy was caused due ________________________

    Right Option : D
    View Explanation

    Students / Parents Reviews [10]