Environmental Pollution MCQs

1. The gaseous layer that surrounds the Earth is called:

a) Troposphere b) Lithosphere c) Atmosphere d) Ozonosphere

Correct Answer: c) Atmosphere

Explanation:
The atmosphere is the layer of gases surrounding Earth, held by gravity. It consists of nitrogen (78%), oxygen (21%), and trace gases. The atmosphere protects life by absorbing UV radiation, regulating temperature, and reducing temperature extremes.

2. Toxic gases are primarily released by:

a) Motor vehicles b) Bullock carts c) Electric bikes d) Bicycles

Correct Answer: a) Motor vehicles

Explanation:
Motor vehicles burning fossil fuels are major sources of toxic gases like carbon monoxide (CO), nitrogen oxides (NOx), and volatile organic compounds (VOCs). A single car emits about 4.6 metric tons of CO₂ annually. Electric vehicles produce zero direct emissions.

3. The innermost layer, the troposphere, extends ___ km above sea level at the equator and ___ km over the poles.

a) 17 and 8 b) 8 and 17 c) 10 and 5 d) 5 and 10

Correct Answer: a) 17 and 8

Explanation:
The troposphere is thicker at the equator (17 km) due to thermal expansion and thinner at poles (8 km). It contains 75% of the atmosphere's mass and nearly all weather phenomena. Temperature decreases with altitude (6.5°C per km) in this layer.

4. The temperature reversal in the troposphere is called:

a) Diapauses b) Thermoregulatory c) Tropopause d) Diurnal

Correct Answer: c) Tropopause

Explanation:
The tropopause is the boundary between troposphere and stratosphere where temperature stops decreasing with height. Its altitude varies from 8 km (poles) to 17 km (equator). Commercial jets fly near the tropopause to avoid weather disturbances.

5. The second layer of the atmosphere is:

a) Troposphere b) Ionosphere c) Stratosphere d) Gasosphere

Correct Answer: c) Stratosphere

Explanation:
Atmospheric layers from Earth upward: 1) Troposphere, 2) Stratosphere (12-50 km), 3) Mesosphere, 4) Thermosphere. The stratosphere contains the ozone layer which absorbs UV radiation. Temperature increases with altitude here due to ozone absorption.

6. The Bhopal Gas Tragedy (1984) was caused by:

a) CO₂ b) Methyl Isocyanate (MIC) c) Methane d) Oxygen

Correct Answer: b) Methyl Isocyanate (MIC)

Explanation:
The Bhopal disaster occurred when water entered a MIC storage tank at Union Carbide's pesticide plant. 40 tons of MIC gas leaked, killing 3,787 people immediately and affecting 500,000 more. It remains the world's worst industrial disaster.

7. The "Great Smog of London" was due to:

a) Water pollution b) Coal burning & stagnant air c) Nuclear testing d) Deforestation

Correct Answer: b) Coal burning & stagnant air

Explanation:
The 1952 London smog lasted 5 days (Dec 5-9) when cold weather increased coal burning and an anticyclone caused air stagnation. PM levels reached 14x normal, SO₂ 7x normal. Caused 4,000 immediate deaths and 8,000 more subsequently, leading to the Clean Air Act 1956.

8. Catalytic converters in vehicles reduce:

a) Noise b) CO, NOx & Hydrocarbons c) Soil erosion d) Water pollution

Correct Answer: b) CO, NOx & Hydrocarbons

Explanation:
Catalytic converters use platinum/palladium/rhodium catalysts to convert: CO → CO₂, NOx → N₂, and unburned hydrocarbons → CO₂ + H₂O. Mandatory since 1975 in the US, they reduce emissions by 90% but require unleaded fuel (lead poisons the catalyst).

9. The "3R principle" stands for:

a) Run, Relax, Rejoice b) Reduce, Reuse, Recycle c) Rain, River, Reservoir d) None of the above

Correct Answer: b) Reduce, Reuse, Recycle

Explanation:
The waste hierarchy prioritizes: 1) Reduce (prevent waste generation), 2) Reuse (use items multiple times), 3) Recycle (process materials into new products). Recycling 1 ton of paper saves 17 trees, 7,000 gallons water, and 4,000 kWh energy.

1. Basics of Environmental Pollution

2. Case Studies on Pollution

3. Pollution Control Measures

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