UPSC General Studies Sample Paper General Studies Sample Paper-1

  • question_answer
    Which of the following are examples of primary pollutants?
    1. Sulphur Dioxide         
    2. Peroxyacetyl Nitrate (PAN)
    3. Particulate matters     
    4. Carbon Monoxide
    5. CFC
    Select the correct answer using the codes given below.

    A)  1, 2 and 4                    

    B)  1, 3 and 5      

    C)  I, 4 and 5                    

    D)  All of these

    Correct Answer: C

    Solution :

    [c] Primary and Secondary Pollutant A primary pollutant is an air pollutant emitted directly from a source. A secondary pollutant is not directly emitted as such, but forms when other pollutants (primary pollutants) react in the atmosphere. Primary Pollutants Sulphur dioxide \[(S{{O}_{2}})\] produced from burning of coal mainly in thermal power plants. It causes smog and acid rain. Nitrogen Oxide\[(N{{O}_{2}})\]causes smog and acid rain. It is produced from burning fuels including petrol, diesel and coal. Carbon monoxide \[(CO)\] is a product by incomplete combustion of fuel such as natural gas, coal or wood. Chlorofluorocarbons (CFCs) released mainly from refrigeration. These gases combine with few other gases, which leads to reduction of the ozone layer that protects the Earth from harmful ultraviolet rays of the Sun. Carbon dioxide\[(C{{O}_{2}})\], greenhouse gas, emitted from combustion. Suspends Particulate Matter (SPM), include smoke, dust and vapour that can remain suspended for extended periods and can be introduced in the environment as primary as well as secondary pollutants. Toxic metals, such as lead, cadmium and copper can enter in the environment through petrol, hair dye product paints, batteries etc. Volatile Organic Compounds (VOC), sue as hydrocarbon fuel vapours and solvents, ammonia (NH emitted from agricultural processes. Odours from garbag sewage and industrial processes. Radioactive pollutants produced by nuclear explosions and war explosives and nature processes such as radon. Secondary Pollutants Particulate matter formed from gaseous primary pollutants and compounds in photochemical smog such as nitrogen dioxide. Ground level ozone (03) formed from\[N{{O}_{2}}\]and VOCs, Peroxyacetyl Nitrate (PAN) similarly formed from\[N{{O}_{2}}\] and VOCs.

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