This set of Pollution Control Multiple Choice Questions & Answers (MCQs) focuses on “Characteristics and Sources of Particulates – Set 2”.
1. What is the state of aerosol particles?
a) Solids and liquids
b) Solids and gases
c) Gases and liquids
d) Liquids only
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Explanation: Aerosols are made of both solid and liquid particles. The size of these particles is so small that they act like colloidal systems when in the atmosphere. Aerosols are not gaseous in nature.
2. Which of the following particulates are larger in size than aerosols?
a) Smoke
b) Dust
c) Fumes
d) Mist
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Explanation: Dust particles have a significant size range. The lower limit of dust particles (1 micron), is the upper limit of aerosols. Liquid and solid particles in the atmosphere smaller than 1 micron may be called aerosols.
3. Which of the following size ranges of particulates are the most prominent in urban areas?
a) 1 micron to 10 microns
b) 0.1 micron to 0.5 microns
c) 0.1 micron to 10 microns
d) 0.1 microns to 100 microns
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Explanation: In urban regions, particulates (dust, mist, fumes aerosols, et cetera) that fall into the size range of 0.1 microns to 10 microns have high concentrations. Such particles are produced in these areas, from combustion and other industrial activities, and remain in these areas.
4. Which factor determines the chemical composition of particulates?
a) The atmosphere pressure
b) Their treatment
c) Temperature of the atmosphere
d) Their origin
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Explanation: The chemical composition of particulates depends on their sources and their formation. For example, coal dust is chemically different from the cement dust because these sources are separate.
5. Which kind of particulates are a primary health concern?
a) Metals and their salts
b) Organic compounds
c) Carbon dioxide
d) Sulphates
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Explanation: Metals and their salts have many health concerns. These materials are toxic in nature and accumulate in living organisms. Additionally, their sizes are very small, making it easy to enter living organisms.
6. Which of the following particulates falls into the size range of 0.05 to 1 micron?
a) Cement dust
b) Oil smoke
c) Virus
d) Mist
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Explanation: Oil smoke particles have sizes ranging from 0.05 micrometres to 1 micrometre. In general, cement dust and mists have much larger sizes. On the other hand, viruses have much smaller sizes.
7. Which of the following statements is false about dust particles?
a) Smog particles are larger than dust particles
b) Viruses are larger than dust particles
c) They have the smallest size amongst all particles
d) They have the largest size amongst all particulates
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Explanation: Generally, most dust particles are visible to the naked eye, and hence, their sizes are larger than most particulate matter. On the other hand, the particulates with the smallest sizes are viruses.
8. What is the size range of smog particles?
a) 0.01 to 1 micrometre
b) 10-2 to 10 micrometres
c) 1 to 100 micrometres
d) 10-2 to 5 micrometres
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Explanation: Smog particles have relatively small particle sizes, ranging from 10-2 to 5 micrometres. Smoke and fog together, which are big particulates, make smog. Naturally, the smoke and fog particles are of comparable sizes.
9. Particulates from which of the following sources are relatively the smallest?
a) Metallurgical
b) Construction
c) Combustion
d) Plants
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Explanation: Combustion particles give rise to relatively the smallest particulates. The construction industry mostly releases dust, which is on the larger side; same with plants (pollen), and metallurgical industry (fumes).
10. Pollen grains have sizes comparable to dust particles.
a) True
b) False
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Explanation: Both pollen grains and dust particles are often visible to the naked eye. Such particles have sizes ranging up to 100 microns. Dust particles can be as small as 1 micron, while pollen grains have a lower limit of 10 microns.
11. Which of the following may form aerosols?
a) Water vapour
b) Hydrocarbons
c) Carbon dioxide
d) Inorganic gases
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Explanation: Hydrocarbons may form aerosols in the atmosphere. These gases react in the atmosphere due to the action of sunlight and other catalysts, to form bigger particles, thus forming aerosols.
12. Particulates from soils and metals do not contain which of the following elements?
a) Calcium
b) Aluminium
c) Silicon
d) Potassium
View Answer
Explanation: Natural particulates originating from the soil contain elements like calcium, aluminium, and silicon. These elements are abundant in the soil, and small light particles may become airborne.
Sanfoundry Global Education & Learning Series – Pollution Control.
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