This set of Pollution Control Multiple Choice Questions & Answers (MCQs) focuses on “Air Pollution Sources & Effects”.
1. Which of the following is a classification of combustion sources?
a) Stationary and Mobile sources
b) Point and line sources
c) Particulates and gaseous
d) Vapours and gases
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Explanation: Stationary and mobile sources are how combustion sources classified. Particulates, gases and vapours may fall into either of the classifications. Both line and point sources can be mobile or stationary.
2. Which of the following is not a method to classify air pollutants?
a) Based on their sources
b) Based on their effects
c) Primary or secondary pollutants
d) Natural or Anthropogenic pollutants
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Explanation: Air pollutants are not classified based on their effects. This is because many pollutants have overlapping effects. The other options given are all distinctions used to classify air pollutant types.
3. What are primary pollutants?
a) Their effects are severe
b) They have industrial sources
c) Their emission is from known sources
d) They are emitted from unknown sources
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Explanation: The origins of primary pollutants are identifiable. Such types of pollutants are emitted directly from their sources, and not from any intermediate sources. This fact makes primary pollutants easily quantifiable.
4. Which of the following is an example of primary pollutants?
a) Ozone
b) Carbon dioxide
c) Smog
d) Sulphuric acid
View Answer
Explanation: Carbon dioxide is an example of a primary air pollutant. Smog, ozone, and sulphuric acid are secondary pollutants made in the atmosphere upon the interaction of various primary pollutants.
5. Which of the following is NOT an example of primary sources of air pollutants?
a) Dust
b) Nitric oxide
c) Hydrogen sulphide
d) Ozone
View Answer
Explanation: Ground-level ozone is a secondary air pollutant. It is formed in photochemical smog when the primary air pollutants react in the presence of light. The other options are examples of primary pollutants.
6. What is meant by secondary air pollutants?
a) Their formation occurs on the surface
b) Their sources are unknown
c) Their sources are known
d) They are formed in the atmosphere
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Explanation: Secondary air pollutants are those pollutants whose formation occurs in the atmosphere. One method of production is by the reaction between primary air pollutants. Another is the reaction between primary pollutants and natural components of air. Such reactions may require sunlight as a catalyst.
7. Which of the following is an example of secondary air pollutants?
a) Smoke
b) Ozone
c) Carbon dioxide
d) Ash
View Answer
Explanation: Ozone is a secondary air pollutant. Its formation primarily occurs in photochemical smog, due to the reaction of hydrocarbons and NOx. In the atmosphere, this reaction occurs in the presence of sunlight.
8. Which of the following is NOT a secondary air pollutant?
a) Nitrogen dioxide
b) Ketones
c) Nitric oxide
d) Aldehydes
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Explanation: Secondary air pollutants are such pollutants whose formation occurs in the atmosphere due to chemical reactions. Nitric oxide is the only given option that is a primary air pollutant. The other options are all examples of secondary pollutants.
9. Carbon dioxide is a primary air pollutant.
a) True
b) False
View Answer
Explanation: Carbon dioxide is generally not considered an air pollutant because it does not have direct effects on humans. Its presence in the atmosphere is of major concern because of its behaviour as a greenhouse gas.
10. Which of the following is NOT a category of air pollutant classification based on their constituents?
a) Natural contaminants
b) Aerosols
c) Gases and vapours
d) Radioactive compounds
View Answer
Explanation: Radioactive compounds fall into the subcategory of gases and vapours. These gases and vapours are naturally present in the atmosphere, or they are released into the atmosphere by human-made processes.
11. Which of the following is a factor that affects the formation of secondary air pollutants?
a) Pressure
b) Humidity
c) Altitude
d) Cloud cover
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Explanation: Humidity or the moisture concentration in the air is a factor that may affect the mechanism of formation of secondary air pollutants. For example, the concentration of sulphuric acid formed depends on the concentration of moisture in the air.
12. Which of the following is not a factor that affects the formation of secondary air pollutants?
a) Moisture concentration
b) Reactant concentration
c) Product concentration
d) Incident sunlight
View Answer
Explanation: Product concentration does not affect reactions from taking place, and hence, are not a factor affecting the formation of secondary air pollutants. The other options all affect the rate of the reaction and the mechanism itself.
13. What is the residence time of carbon dioxide in the atmosphere?
a) Between 2 and 4 years
b) 2 year
c) 4 years
d) Between 4 and 6 years
View Answer
Explanation: Residence time is the duration of time for which gases remain in the atmosphere. Residence time is different for different gases. For carbon dioxide, the residence time is between 2 and 4 years.
14. What is the reason for gases, vapours, particulates, et cetera to get classified as air pollutants?
a) They affect people and the environment
b) They affect people only
c) They affect the environment only
d) They affect the planet
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Explanation: Air pollutants are those materials that directly harm humans and the environment adversely. The concentration of such materials has to be higher than their natural concentrations so that they may be classified as pollutants.
15. Which of the following is the most common way of expression of pollutant concentration in the air?
a) Mass concentration
b) Volume concentration
c) Mass-volume concentration
d) Volume concentration (ppm)
View Answer
Explanation: Mass-volume concentration is the most common way to express pollutant concentration in the air. The concentration of particulates and gases, both, is expressed using this formula.
Sanfoundry Global Education & Learning Series – Pollution Control.
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