Question

Which pollutant is responsible for the destruction of chlorophyll and adversely affects monuments like the Taj Mahal?

• A. Nitrogen oxides
• B. Sulphur oxides
• C. Carbon monoxide
• D. Methane

Answer 1

Answer:

B. Sulphur oxides

• Correct Answer: Option B - Sulphur oxides

• Sulphur oxides, particularly sulphur dioxide (SO₂), are primary air pollutants that have significant negative impacts on both plants and monuments:

• Effect on chlorophyll: Sulphur dioxide damages plant tissues and interferes with photosynthesis by destroying chlorophyll. It enters plant leaves through stomata and forms sulfurous acid when it combines with water, which then breaks down chlorophyll molecules, leading to yellowing of leaves (chlorosis) and reduced plant growth.

• Effect on the Taj Mahal: Sulphur dioxide reacts with moisture in the air to form sulphuric acid, which causes "acid rain." This acidic precipitation attacks the marble of the Taj Mahal (calcium carbonate) through a chemical reaction:

• CaCO₃ + H₂SO₄ → CaSO₄ + H₂O + CO₂

• This reaction converts the white marble into calcium sulfate (gypsum), resulting in yellowing and deterioration of the monument's surface. This phenomenon is known as "marble cancer."