Which causes maximum pollution?

Question

Which causes maximum pollution?

1. A. Carbon dioxide
2. B. Oxygen
3. C. Nitrogen
4. D. Carbon monoxide (Correct answer)

Correct Answer

Option D — Carbon monoxide

Detailed Solution & Explanation

The correct answer is Carbon monoxide.

Key Points

• Carbon monoxide (CO) is a highly toxic pollutant produced by the incomplete combustion of fuels, chiefly in vehicle exhaust.
• It binds to haemoglobin about 200-250 times more readily than oxygen, forming carboxyhaemoglobin and starving the tissues of oxygen.
• Oxygen and nitrogen are normal constituents of clean air, and carbon dioxide is a greenhouse gas rather than a direct poison at ambient levels.

Additional Information

• CO is called the silent killer because it is colourless, odourless and tasteless, giving no warning of exposure.
• India's National Ambient Air Quality Standards monitor CO alongside PM2.5, PM10, SO₂, NO₂, ozone and lead.
• Catalytic converters in vehicles oxidise CO to the far less harmful CO₂.