# NPTEL Air Pollution and Control Week 4 Solutions

This set of MCQ(multiple choice questions) focuses on the NPTEL Air Pollution and Control Week 4 Solutions

### Course layout

Week 0: Assignment Solutions
Week 1: Assignment Solutions

Week 2: Assignment Solutions
Week 3: Assignment Solution
Week 4: Assignment Solution
Week 5: Assignment Solutions
Week 6: Assignment Solutions
Week 7: Assignment Solutions
Week 8: Assignment Solutions
Week 9: Assignment Solutions
Week 10: Assignment Solutions
Week 11: Assignment Solutions
Week 12: Assignment Solutions

NOTE: You can check your answer immediately by clicking show answer button. Moreover, this set of “NPTEL Air Pollution and Control Week 4 Solutions” contains 10 questions.

### NPTEL Air Pollution and Control Week 4 Solutions

Q1. What is the standard unit of the (σz) standard deviation of the vertical distribution of plume concentration?

a) m
b) m/s
c) g/s
d) μg/m3

Q2. Which of the following assumptions are associated with the Gaussian plume model?
I.  There is no diffusion in the X-direction
II.  Uniform continuous emission rate
III.  The shape of the plume is conical
IV.  The pollutants are non-reactive gases or aerosol

a) I & II
b) II & IV
c) II, III & IV
d) I, II, III & IV

Q3. The expression for the determination of concentration (C) of a pollutant using the Gaussian dispersion model for a line source is given as: The above equation is generally used if

a) Φ = 0°
b) Φ = 20°
c) Φ > 20°
d) Φ > 20°

Q4. What is/are the disadvantages of using the gaussian plume model for area sources?
I. Require large amounts of input information
II. Consume large amounts of computer time
III. Involves complexity

a) I
b) II & IV
c) I & III
d) I, II & III

NPTEL Air Pollution and Control Week 4 Solutions

Q5. The buoyancy flux parameter (F) is utilized to calculate the effective height of the stack. The formula for the buoyancy flux parameter (F) is given below:

Where,
Vs = Exit velocity Ds = Stack DiameterTs = Exit Temperature Ta = Ambient air temperature
The unit of F is

a) m2/s
b) m4/s2
c) m4/s3
d) m4/s4

Q6. To calculate the maximum concentration using the Gaussian plume model, σz is given as

a) √H/2
b) H/√2
c) H/2
d) H√2

Q7. A part of the atmosphere that behaves in a coherent way concerning the dispersion of air pollutants is known as

a) Pollution potential
b) Atmospheric stability
c) Ventilation Coefficient
d) Airshed

Q8. The available assimilation capacity (AAC) is given as

a) AAC = Permissible Standard (NAAQS) – Ambient Pollutant concentration
b) AAC = Permissible Standard (NAAQS) + Ambient Pollutant concentration
c) AAC = Permissible Standard (NAAQS) x Ambient Pollutant concentration
d) AAC = Permissible Standard (NAAQS) / Ambient Pollutant concentration

Q9. The basic equation for emission estimation is

a) Emission = Emission Factor – Activity Data
b) Emission = Emission Factor + Activity Data
c) Emission = Emission Factor × Activity Data
d) Emission = Emission Factor / Activity Data

NPTEL Air Pollution and Control Week 4 Solutions

Q10. The comprehensive stock of all the pollution-emitting sources and emissions in a given region with a specific time period is called

a) Emission inventory
b) Emission factor
c) Emission correction coefficient
d) Emission norm

### Previous Year- NPTEL Air Pollution and Control Week 4 Solutions

Q1. The Gaussian plume model-based estimations of the concentrations of a pollutant are not reliable beyond the radius of approximately _________

a) 15km
b) 20km
c) 25km
d) 30km

Q2. In the downwind direction from an air pollution source, with the increasing distance, the lateral and vertical dispersion coefficients will

a) Remain constant
b) Decrease
c) Increase
d) Initially increase and then decrease

Q3. Which of the following is not an example of line source of air pollution?

a) Motor Vehicles travelling along a straight section of a highway
b) Agricultural burning along the edge of a field
c) Fire in a large area of a forest
d) A line of industrial sources on the bank of a river etc

Answer: c) Fire in a large area of a forest

Q4. The expression for determination of concentration (C) of a pollutant using Gaussian dispersion model for a line source is given as:

NPTEL Air Pollution and Control Week 4 Solutions

Q5. Sulfur dioxide is emitted at a rate of 150 g/s from a stack with an effective height of 60 m. The wind speed at stack height is 5 m/s, and the atmosphere stability class is D for the overcast day. (Given, σ= 38 m and σ= 19 m). Ground-level concentration along the center line at a distance of 500 m from the stack, in micrograms per cubic meter (µg/m3).

a) 40 µg/m3
b) 60 µg/m3
c) 90 µg/m3
d) 100 µg/m3

Q6. Estimate the total hydrocarbon concentration at a point 300 m downwind from an expressway at 5:30 P.M on an overcast day. The wind is perpendicular to the highway and has a speed of 4 m/s. The traffic density along the highway is 8000 vehicles per hour, and the average vehicle speed is 40 mi/hr. The average vehicle emission rate of hydrocarbons is 2×10-2  g/s.

a) 32 µg/m3
b) 42 µg/m3
c) 28 µg/m3
d) 58 µg/m3

Q7. ___________ is the product of maximum mixing depth/height and the average wind speed within the mixing layer for a given region.

a) Ventilation Coefficient
b) Pollutant Concentration
c) Pollution potential
d) Atmospheric stability

Q8. ________________ of an air environment is the maximum amount of pollution load that can be discharged into it without violating the best designated use of the air resource in the planning region.

a) Assimilative capacity
b) Airshed
c) Ventilation coefficient
d) None of the above

Q9. __________ is an average representative value that is related to the quantity of an air pollutant released to the atmosphere due to a particular activity.

a) Correction factor
b) Activity Data
c) Assimilative capacity
d) Emission factor

NPTEL Air Pollution and Control Week 4 Solutions

Q10. The basic equation for estimating the emissions from a particular sector is given as the product of :

a) Activity data and Emission factor
b) Activity data and Concentration of a pollutant
c) Emission factor and Average wind speed
d) Emission factor and Concentration of a pollutant

Answer: a) Activity data and Emission factor

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