NPTEL Air Pollution and Control Assignment Answers 2025
1. Which of the following formula is given for calculating the mean wind speed at plume height?
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2. How does the wind angle direction with respect to the receptor affect the total concentration of air pollutants?
- It increases with an increase in wind angle direction.
- It remains constant regardless of wind angle direction.
- It decreases as the wind angle direction increases.
- It is unaffected by the wind angle direction.
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3. The expression for the determination of concentration (C) of a pollutant using the Gaussian dispersion model for a line source is given as:
What is the standard unit of the (σz) standard deviation in the given equation
- meter/second (m/s)
- gram/second (g/s)
- meters (m)
- micrograms/cubic meters (μg/m3)
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4. The initial spread for the interpretation of the area source is given as
- σyo = S/1.2
- σyo = S/2.2
- σyo = S/3.2
- σyo = S/4.2
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5. On a highway, a lot of vehicles traveling daily release harmful chemical emissions. Consider the average emission rate from the vehicles of a pollutant P1 as 0.05 g/s. Determine the total chemical concentration of pollutant P1 at a point 600 m downwind from the highway on an overcast day. Let the wind be perpendicular to the highway with a speed of 5 m/s. The number of vehicles per unit length (in m) is 0.18 m.
- 1.44 μg/m3
- 14.44 μg/m3
- 2.88 μg/m3
- 28.88 μg/m3
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6. What does “assimilative capacity” of air environment refer to?
- The amount of pollution that can be discharged without violating water standards
- The maximum amount of pollution that can be discharged without violating air quality standards
- The ability of air to remain stagnant without pollutants spreading
- The rate at which pollutants are produced in an industrial area
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7. What does a higher ventilation coefficient indicate?
- Poor air quality due to stagnation
- Inefficient dispersal of pollutants
- Efficient atmospheric dispersion and better air quality
- Increased levels of hazardous pollution
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8. The height of the layer in which air pollutants or any constituents emitted or entrained into it is vertically dispersed due to turbulence and convection; it is called
- Mixing height
- Effective height
- Plume rise
- Ventilation coefficient
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9. How is the emission factor (EF) expressed?
- As the ratio of pollutants to air quality index
- As mass of pollutants divided by a volume or weight of raw material
- As the proportion of emission to meteorological variations
- As the concentration of pollutants in the mixing layer
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10. What does a gridded emission inventory provide?
- Information on global wind patterns
- Locational information of emissions of air pollutants and their sources
- Data on rainfall and its effect on pollution
- The chemical composition of pollutants in the atmosphere
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