INSIGHT UPSC QUIZ

Science & Technology General Science
Q.

Read the following statements carefully in the context of ‘particulate pollutants’?

1. Smoke particulates consist of gaseous or mixture of gaseous and liquid particles formed during combustion of organic matter.

2. Dust is composed of fine solid particles produced during crushing, grinding and attribution of solid materials.

3. Mists are produced by particles of spray liquids and by condensation of vapours in air.

4. Fumes are generally obtained by the condensation of vapours during sublimation, and boiling.

Which of the statements given above are correct?

Explanation:

ANSWER: (B) 

  • Smoke particulates consist of solid or mixture of solid and liquid particles formed during combustion of organic matter. (Thus, Statement 1 is not correct)
  • Examples are cigarette smoke, smoke from burning of fossil fuel, garbage and dry leaves, oil smoke etc.
  • Dust is composed of fine solid particles (over 1μm in diameter), produced during crushing, grinding and attribution of solid materials. (Thus, Statement 2 is correct) 
  • Sand from sand blasting, saw dust from wood works, pulverized coal, cement and fly ash from factories, dust storms etc., are some typical examples of this type of particulate emission.
  • Mists are produced by particles of spray liquids and by condensation of vapours in air. (Thus, Statement 3 is correct)
  • Examples are sulphuric acid mist and herbicides and insecticides that miss their targets and travel through air and form mists.
  • Fumes are generally obtained by the condensation of vapours during sublimation, distillation, boiling and several other chemical reactions. (Thus, Statement 4 is correct)
  • Generally, organic solvents, metals and metallic oxides form fume particles.

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