Pollutants, Ozone Depletion and Greenhouse Gases

Attempt the quiz above first, then review every question with its correct answer and a short explanation below.

1. Q1.The ozone layer protects life on Earth by absorbing:

   • A.visible light
   • B.radio waves
   • C.harmful ultraviolet radiation✓ Correct Answer
   • D.sound waves

   Explanation: It lies in the stratosphere.

2. Q2.Which gas is the main contributor to the greenhouse effect among the following?

   • A.argon
   • B.neon
   • C.helium
   • D.carbon dioxide✓ Correct Answer

   Explanation: It traps outgoing heat radiation.

3. Q3.Acid rain is mainly caused by oxides of:

   • A.carbon only
   • B.hydrogen
   • C.sulphur and nitrogen✓ Correct Answer
   • D.helium

   Explanation: They form sulphuric and nitric acids in the air.

4. Q4.Which chemicals are mainly responsible for ozone layer depletion?

   • A.carbon dioxide
   • B.chlorofluorocarbons (CFCs)✓ Correct Answer
   • C.methane
   • D.ammonia

   Explanation: Chlorine atoms from CFCs destroy ozone molecules.

5. Q5.Which poisonous gas from vehicle exhaust binds to haemoglobin?

   • A.oxygen
   • B.nitrogen
   • C.carbon monoxide✓ Correct Answer
   • D.argon

   Explanation: It reduces the oxygen-carrying capacity of blood.

6. Q6.Plastic waste is a pollution problem mainly because it is:

   • A.non-biodegradable✓ Correct Answer
   • B.soluble in water
   • C.a fertiliser
   • D.a gas

   Explanation: It persists in the environment for very long.

7. Q7.The ozone hole is most prominent over:

   • A.the Sahara
   • B.the Amazon
   • C.Antarctica✓ Correct Answer
   • D.India

   Explanation: Polar stratospheric clouds help the destruction every spring.

8. Q8.The Montreal Protocol (1987) deals with:

   • A.reducing carbon dioxide only
   • B.protecting wetlands
   • C.trade in wildlife
   • D.phasing out ozone-depleting substances✓ Correct Answer

   Explanation: It is regarded as one of the most successful environmental treaties.

9. Q9.Minamata disease is caused by poisoning from:

   • A.lead
   • B.cadmium
   • C.mercury✓ Correct Answer
   • D.arsenic

   Explanation: It was first noticed in Japan in fish-eating communities.

10. Q10.The Bhopal gas tragedy of 1984 was caused by the leak of:

    • A.methyl isocyanate✓ Correct Answer
    • B.carbon monoxide
    • C.chlorine
    • D.ammonia

    Explanation: It leaked from a pesticide plant.

11. Q11.BOD stands for:

    • A.biological ozone depletion
    • B.biochemical oxygen demand✓ Correct Answer
    • C.basic organic density
    • D.bulk oxygen deficit

    Explanation: A higher BOD indicates more organic pollution in water.

12. Q12.Excess nutrients such as nitrates and phosphates in a lake cause:

    • A.desertification
    • B.acid rain
    • C.ozone depletion
    • D.eutrophication✓ Correct Answer

    Explanation: Algal blooms then deplete oxygen in the water.

13. Q13.Photochemical smog is formed from:

    • A.nitrogen oxides and hydrocarbons in sunlight✓ Correct Answer
    • B.carbon dioxide and nitrogen
    • C.oxygen and argon
    • D.water vapour and helium

    Explanation: It contains ozone and peroxyacetyl nitrate at ground level.

14. Q14.Which greenhouse gas is released in large amounts from paddy fields and cattle?

    • A.argon
    • B.neon
    • C.oxygen
    • D.methane✓ Correct Answer

    Explanation: Anaerobic decay of organic matter produces it.

15. Q15.The thickness of the ozone layer is measured in:

    • A.decibels
    • B.pascals
    • C.lux
    • D.Dobson units✓ Correct Answer

    Explanation: About 300 Dobson units is typical globally.

16. Q16.PM2.5 refers to airborne particles with a diameter of:

    • A.2.5 micrometres or less✓ Correct Answer
    • B.2.5 millimetres
    • C.25 micrometres
    • D.2.5 centimetres

    Explanation: Such fine particles enter deep into the lungs.

17. Q17.The Kyoto Protocol (1997) seeks to reduce emissions of:

    • A.greenhouse gases✓ Correct Answer
    • B.only radioactive waste
    • C.only noise
    • D.only plastics

    Explanation: It set targets for developed countries.

18. Q18.Rainwater is considered acid rain when its pH falls below about:

    • A.7.0
    • B.5.6✓ Correct Answer
    • C.8.5
    • D.10.0

    Explanation: Normal rain is slightly acidic because of dissolved carbon dioxide.

19. Q19.Itai-itai disease is caused by poisoning from:

    • A.mercury
    • B.cadmium✓ Correct Answer
    • C.iron
    • D.sodium

    Explanation: It was linked to cadmium in rice grown with polluted water.

20. Q20.Ozone is formed in the stratosphere from:

    • A.nitrogen under heat
    • B.oxygen under ultraviolet radiation✓ Correct Answer
    • C.carbon dioxide under pressure
    • D.water vapour under cold

    Explanation: UV splits O2 and the atoms combine with O2 to give O3.