SSC Ecology And Environment Sample Paper NCERT Sample Paper-6

  • question_answer
    In almost all Indian metropolitan cities like Delhi, the major atmospheric pollutant(s) is/are

    A)  Suspended particulate matter (SPM)

    B)  Oxides of sulphur

    C)  Carbon dioxide and carbon monoxide

    D)  Oxides of nitrogen

    Correct Answer: A

    Solution :

    [a] Suspended particulate matter (SPM) are finely divided solids or liquids that may be dispersed through the air from combustion processes, industrial activities or natural sources. Particulate Matter is the general term used for a heterogeneous mixture of solid particles and liquid droplets found in the air, including dust, dirt, soot, smoke, and liquid droplets. Particles can be suspended in the air for long periods of time. Some particles are large or dark enough to be seen as soot or smoke. Others are so small that individually they can only be detected with an electron microscope. PM can be a primary or secondary pollutant. "Primary" particles, such as dust or black carbon (soot) are directly emitted into the air. They come from a variety of sources such as cars, trucks, buses, factories, construction sites, tilled fields, unpaved roads, stone crushing, and burning of wood. "Secondary"-particles are formed in the air from the chemical change of primary gaseous emissions. They are indirectly formed when gases from burning fuels react with sunlight and water vapour. These can result from fuel combustion in motor vehicles, at power plants, and in other industrial processes.


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