Free Atmospheric Pollution MCQs with Answers

1. CFCs is used in:

• A. Refrigeration
• B. Aerosol spray
• C. Plastic foam industry
• D. All of above

Explanation: Chlorofluorocarbons (CFCs) are nontoxic, nonflammable chemicals containing atoms of carbon, chlorine, and fluorine. They are used in the manufacture of aerosol sprays, blowing agents for foams and packing materials, as solvents, and as refrigerants.

2. Identify greenhouse gases:

• A. CH4 and O2
• B. CO2 and H2O Vapours
• C. NO2 and H2O Vapours
• D. CH4 and O3

Explanation: This is correct as it includes both carbon dioxide (CO2) and water vapor (H2O), which are major greenhouse gases contributing to the greenhouse effect on Earth.

3. Name which one of the following gas is not pollutant?

• A. Sulphur dioxide
• B. Carbon monoxide
• C. Carbon dioxide
• D. Nitrogen dioxide

Explanation: Among sulfur dioxide (SO2), carbon monoxide (CO), carbon dioxide (CO2), and nitrogen dioxide (NO2), carbon dioxide (CO2) is not typically considered an air pollutant in the same sense as the others.Carbon dioxide is a naturally occurring gas in the Earth's atmosphere and is essential for life on Earth. It is produced through natural processes such as respiration and volcanic eruptions, as well as human activities such as combustion of fossil fuels and deforestation. While carbon dioxide is a greenhouse gas and contributes to climate change when present in excessive amounts, it is not directly toxic to humans at typical ambient concentrations.On the other hand, sulfur dioxide, carbon monoxide, and nitrogen dioxide are all considered air pollutants due to their harmful effects on human health and the environment.

4. Peroxyacetyl Nitrate (PAN) is an irritant to human beings and it affects:

• A. Eyes
• B. Nose
• C. Stomach
• D. Skin

Explanation: Nose is correct because Peroxyacetyl Nitrate (PAN) primarily affects the respiratory system, causing irritation to the nose, throat, and lungs.

5. Choose the correct statement:

• A. Ultraviolet radiation from sun causes a reaction that produces ozone
• B. Ozone hole is depletion in total amount of O
• C. A single chlorine free radical can destroy 10000 ozone molecules
• D. AII of above

Explanation: Ultraviolet radiations cause photochemical splitting of oxygen molecules in the stratosphere. The nascent oxygen combines with molecular oxygen to form ozone. In troposphere nascent oxygen comes from nitrogen dioxide. Option B is incorrect because ozone depletion does not reduce the amount of oxygen atoms, however it reduces the amount of ozone (O3) by converting it to oxygen gas O2. Option C is incorrect because a single chloride free radical can destroy upto 100,000 ozone molecules.

6. Which of the following is not an air pollutant?

• A. N2
• B. N2O
• C. NO
• D. CO

Explanation: Nitrogen is an inert gas - meaning it doesn't chemically react with other gases - and it isn't toxic

7. Natural rain forms _ in the presence of carbon dioxide in the air.

• A. Smog
• B. Ozone
• C. Carbonic acid
• D. Chlorofluorocarbons

Explanation: CO2+H2O->H2CO3 This is how carbonic acid is formed from water.

8. The major source of unburnt hydrocarbons in the atmosphere is/are:

• A. Petroleum
• B. Natural gas
• C. Automobiles
• D. Human beings

Explanation: There are many sources of unburned hydrocarbons. Unburned hydrocarbons (UHC) are typically an output of incomplete combustion due to unfavorable engine design, low fuel quality, or failure in the control system. Sometimes unburned hydrocarbons are released into the air during incomplete combustion. Burning fossil fuels, including gasoline in automobile engines, releases some hydrocarbons into the air. In a typical urban environment, the atmospheric concentration of hydrocarbons is around 3 ppm (parts per million).

9. Coal contain sulphur:

• A. 1 - 3 %
• B. 2 - 5 %
• C. 1 - 9 %
• D. 3 - 8 %

Explanation: Organic sulfur is chemically bonded to the carbon atoms in the coal. The organic sulfur content of most coals ranges from 0.5% to about 2%.

10. What is the most common gas in the environment?

• A. N2
• B. CO2
• C. O2
• D. He

Explanation: The most abundant naturally occurring gas is nitrogen (N2), which makes up about 78% of air. Oxygen (O2) is the second most abundant gas at about 21%. The inert gas argon (Ar) is the third most abundant gas at 0.93%.