Question

Which of the following is NOT an air pollution control measure/ technique?

• A. Bag houses
• B. Electrostatic Precipitators
• C. High Volume Air Sampler
• D. Cyclone Chambers

Hint:

Particulate control devices remove pollutants from flue gas:
- Gravity settling chambers
- Cyclone separators
- Baghouse fabric filters
- Electrostatic precipitators (ESP)
- Venturi scrubbers
Samplers (e.g., High Volume Sampler) only measure pollutants; they do not control emissions.

Answer 1

The Correct Option is C

Concept:
Industrial air pollution management relies on engineering devices designed to capture, separate, or neutralize particulate matter and gaseous pollutants from industrial flue gas emissions before they are discharged through stacks.
In contrast, environmental monitoring instruments are used to measure the concentration of ambient pollutants in the atmosphere.

Step 1: Evaluation of Air Pollution Control Technologies:
1. Bag houses (Fabric Filters): Industrial particulate control units containing long, tubular fabric filter bags. When dust-laden flue gas passes through the fabric, particulate matter is retained on the bag surface, achieving capture efficiencies exceeding $99\%$ for fine particles.
2. Electrostatic Precipitators (ESP): Filtration devices that use high-voltage electrode wires to ionize incoming gas streams and charge passing particles. The negatively charged particles are then attracted to grounded collecting plates, effectively removing fly ash from coal-fired power plants.
3. Cyclone Chambers (Centrifugal Collectors): Inertial separators that utilize centrifugal force generated by a vortex flow to separate heavier particulates ($> 10\,\mu\text{m}$) from flue gas streams.

Step 2: Identification of Monitoring Equipment:
High Volume Air Sampler (HVAS): This is an analytical sampling instrument used in ambient air quality stations. It draws a measured volume of ambient air through a pre-weighed glass-fiber filter at a rate of $1.1$ to $1.7\text{ m}^3/\text{min}$ over a 24-hour period to measure the concentration of Suspended Particulate Matter (SPM and $\text{PM}_{10}$).
The High Volume Air Sampler is a measuring instrument used for ambient air analysis, not an industrial abatement or control device.
Final Answer:
A High Volume Air Sampler is an air quality monitoring instrument rather than a pollution control technique, corresponding to option (C).