SSC Ecology And Environment Sample Paper NCERT Sample Paper-2

  • question_answer
    PAN (Peroxyacetyl Nitrate) is an important constituent of photochemical smog. It is a

    A)  Primary pollutant

    B)  secondary pollutant

    C)  Natural pollutant

    D)  corrollary pollutant

    Correct Answer: B

    Solution :

    [b] 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. Peroxyacetyl nitrate, or PAN, is an oxidant more stable than ozone. Hence, it is better capable of long-range transport than ozone. It serves as a carrier for oxides of nitrogen (NOx) into rural regions and causes ozone formation in the global troposphere. The formation of PAN on a secondary scale becomes an issue when ethanol is used as an automotive fuel. Acetaldehyde emissions increase, which subsequently react in the atmosphere to form smog. Whereas ethanol policies solve domestic oil supply problems, they drastically exacerbate air quality conditions.


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