Question

What is the CORRECT match between the air pollutants and treatment techniques given in the table

Air Pollutants		Treatment techniques
P	NO2	i	Flaring
Q	SO2	ii	Cyclonic separator
R	CO	iii	Lime scrubbing
S	Particles	iv	NH3 injection

• A. P-i, Q-ii, R-iii, S-iv
• B. P-ii, Q-i, R-iv, S-iii
• C. P-ii, Q-iii, R-iv, S-i
• D. P-iv, Q-iii, R-i, S-ii

Answer 1

The Correct Option is D

To address this question about matching air pollutants with their respective treatment techniques, let's break down each option and explain the correct matches:

1. NO₂ (Nitrogen Dioxide): A common treatment technique for nitrogen oxides (NOx), such as NO₂, is the injection of ammonia (NH₃) during selective catalytic reduction (SCR) or selective non-catalytic reduction (SNCR) processes. This helps to reduce NO₂ emissions by converting them to harmless nitrogen gas (N₂).

   Thus, match P-iv: NO₂ - NH₃ injection.

2. SO₂ (Sulfur Dioxide): Lime scrubbing is frequently used to treat sulfur dioxide emissions in flue gases by utilizing lime or limestone to form calcium sulfite or calcium sulfate, which can be easily handled as a solid waste.

   Thus, match Q-iii: SO₂ - Lime scrubbing.

3. CO (Carbon Monoxide): Flaring is a treatment technique used to burn off waste gases and is effective in converting carbon monoxide (CO) to carbon dioxide (CO₂) in industrial settings, thus reducing its impact.

   Thus, match R-i: CO - Flaring.

4. Particles: Cyclonic separators are devices designed to remove particulates from air, gas, or liquid streams without using filters, through vortex separation.

   Thus, match S-ii: Particles - Cyclonic separator.

Accordingly, the correct answer is P-iv, Q-iii, R-i, S-ii.