SMOG : Environment for UPSC Exams

SMOG : Environment for UPSC Exams

  • The term "smog" was first used in London during the early 1900's to describe the combination of smoke and fog. What we typically call "smog" today is a mixture of pollutants but is primarily made up of ground-level ozone.

  • Ozone can be beneficial or harmful depending on its location. The ozone located high above the Earth in the stratosphere protects human health and the environment, but ground-level ozone is responsible for the choking, coughing, and stinging eyes associated with smog.

  • Smog usually is produced through a complex set of photochemical reactions involving volatile organic compounds (VOC's) and nitrogen oxides in the presence of sunlight that result in the production of ozone.

  • Smog-forming pollutants come from many sources, such as automobile exhausts, power plants, factories, and many consumer products, including paints, hair spray, charcoal starter fluid, solvents, and even plastic popcorn packaging.

  • Major smog occurrences often are linked to heavy motor vehicle traffic, high temperatures, sunshine, and calm winds.

  • In Delhi, smog severity is often aggravated by stubble burning in neighbouring agricultural areas.

  • Smog is made up of a combination of air pollutants that can injure health of people with heart and lung conditions such as emphysema, bronchitis, and asthma and further harm the environment, and cause property damage.

  • This mixture of air pollutants may include the following:

    • Aldehydes

    • Nitrogen oxides, particularly nitric oxide and nitrogen dioxide

    • Peroxyacyl nitrates

    • Tropospheric ozone

    • Volatile organic compounds

  • Photochemical smog is the chemical reaction of sunlight, nitrogen oxides and volatile organic compounds in the atmosphere, which leaves airborne particles and ground-level ozone.

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