This set of Pollution Control Multiple Choice Questions & Answers (MCQs) focuses on “Sources and Classification of Air Pollutants – Set 4”.
1. What is the approximate residence time of nitric oxide in the atmosphere?
a) 2 days
b) 5 days
c) 2 years
d) 5 years
View Answer
Explanation: Residence time of gases in the atmosphere is the time duration for which it remains in the atmosphere, which is five days for nitric oxide. Nitric oxide is converted rapidly to nitric acid in the atmosphere.
2. What is a secondary source of sulphur dioxide?
a) Oxidation of hydrogen sulphide
b) Industrial combustion
c) Breakdown of sulphuric acid
d) Reduction of sulphur trioxide
View Answer
Explanation: The primary source of sulphur dioxide is from industrial combustion. A secondary source is the oxidation of hydrogen sulphide, which is produced naturally in marshes and swamps found naturally.
3. Which of the following is the prime source of hydrocarbons?
a) Combustion
b) Industrial production
c) Waterbodies
d) Volcanic eruptions
View Answer
Explanation: Natural sources like water bodies are the prime sources of hydrocarbons. Hydrocarbons are released from swamps and marshes. These natural sources are a significant point of origin of methane.
4. Petroleum refining and use are the largest source of hydrocarbon air pollutants.
a) True
b) False
View Answer
Explanation: Refining and use of petroleum generate the bulk of hydrocarbon air pollutants. Although other sources do produce a significant number of hydrocarbons, they release much less in comparison.
5. Which of the following are not primary sources of carbon monoxide?
a) Incomplete combustion of fuels
b) Complete combustion of fuels
c) Oxidation of methane
d) Oxidation of Methanal
View Answer
Explanation: The incomplete combustion of fuels produces carbon monoxide. Oxidation of methane and formaldehyde also give rise to carbon dioxide in the atmosphere. Oxidation accounts for more than 80% of its formation.
6. What are the two types of smog?
a) Sulphurous and nitrogenous
b) Photochemical and carbonaceous
c) Photochemical and nitrogenous
d) Photochemical and sulphurous
View Answer
Explanation: There are two chief types of smog. These types are photochemical smog and sulphurous smog. Both of these types occur over urban areas, mostly due to weather conditions like temperature.
7. Why does photochemical smog occur?
a) High temperatures
b) Limited movement of air
c) In urban areas
d) Low temperatures
View Answer
Explanation: When there is limited air movement in urban areas, photochemical smog settles over these areas. This type of smog gives rise to peroxyacetyl nitrate or PAN, which is very harmful for plant and animal health.
8. Why does sulphurous smog occur?
a) High tempera
b) Limited movement of air currents
c) In urban areas
d) Low temperatures
View Answer
Explanation: This type of fog occurs over urban areas in low temperatures. These temperatures are as low as 10 degrees Celsius. Another reason for the occurrence of sulphurous smog is calm weather conditions.
9. Which of the following compounds is produced in the air in photochemical smog?
a) Peroxyacetyl nitrate
b) Sulphur dioxide
c) Smoke
d) Carbon dioxide
View Answer
Explanation: The action of light causes many secondary pollutants to form in photochemical smog. One such material is peroxyacetyl nitrate (PAN). This pollutant is harmful for the health of plants, animals and humans.
10. How is ppm concentration (yppm) calculated in terms of volume concentration (yp)?
a) yppm = yp
b) yppm = yp / 106
c) yppm = yp * 106
d) yp= yppm * 106
View Answer
Explanation: yppm = yp*106
The remaining three are false. yp is the volume concentration of an air component, and yppm is the volume concentration expressed in parts per million.
11. What are the units of volume concentration?
a) It has no units
b) ppm
c) Cubic centimetre
d) Kilogram per cubic metre
View Answer
Explanation: Volume concentration has no units. It is the ratio of the volume of pollutant, to the sum of the volume of the air and the air pollutant. The nature of this ratio results in the units getting cancelled out.
12. What is the source of oxides of trace metals?
a) Paper and pulp manufacture
b) Organic chemical manufacture
c) Mobile combustion sites
d) Stationary combustion sites
View Answer
Explanation: Generally, stationary combustion sites release oxides of trace metals. Stationary combustion includes incineration and waste burning, which is the final destination of untreatable waste.
13. Which of the following is not a natural source of carbon monoxide?
a) Oceans
b) Crop burning
c) Breakdown of methane
d) Oxidation of formaldehyde
View Answer
Explanation: Crop burning process is an anthropogenic process, so it is not a natural carbon monoxide source. The other given sources of carbon dioxide naturally produce and release it into the atmosphere.
14. Chemical manufacture does not release ammonia.
a) True
b) False
View Answer
Explanation: Manufacture of many chemicals falls under this category. The release of gases depends on the process, while some chemical manufacture processes may give off ammonia, others may not.
15. Which of the following is not a significant source of air pollutants from metallurgical operations?
a) Roasting
b) Smelting
c) Digestors
d) Furnaces
View Answer
Explanation: Roasting, smelting, and furnaces are common ore processing operations. They all release air pollutants, like particulates. On the other hand, digestion is a process used in the pulp and paper industry.
Sanfoundry Global Education & Learning Series – Pollution Control.
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