The Gaussian plume model is the most common air pollution model. It is based on a simple formula that describes the three-dimensional concentration field generated by a point source under stationary meteorological and emission conditions. 

1. AIR
POLLUTION
MODELLING
K U L V E N D R A P A T E L
2 K 1 9 / E N E / 0 5
G a u s s i a n P l u m e
D i s p e r s i o n
M o d e l
D E L H I T E C H N O L O G I C A L U N I V E R S I T Y

2. Dispersion Modelling
• The Gaussian plume model is the most common air pollution model. It is
based on a simple formula that describes the three-dimensional concentration
field generated by a point source under stationary meteorological and
emission conditions.
• Gaussian-based dispersion models are widely used to estimate local pollution
levels.
• The dispersion of plume which is emitted from a chimney is governed by
many factors: wind speed, wind direction, local terrain, turbulence intensity
of atmosphere, temperature, etc.

3. A contaminant plume emitted from a continuous point source, with wind direction aligned with the x-axis. Profiles of concentration are given at two
downwind locations (vertical in red, horizontal in blue) and the Gaussian shape of the plume cross-sections are shown relative to the plume centerline.
From John M. Stockie : The Mathematics of Atmospheric Dispersion Modeling

4. C (𝑥, 𝑦, 𝑧) =
𝑄
2𝜋𝑢𝜎𝑦𝜎𝑧
𝑒
−
𝑦2
2𝜎𝑦
2 0
0
𝑒
−
(𝑧+𝐻)2
2𝜎𝑧
2
+ 𝑒
−
(𝑧−𝐻)2
2𝜎𝑧
2
C = Pollution concentration (g/𝑚3
)
Q = pollutant emission rate (g/s)
y = lateral distance from the centerline of plume (m)
z = height off the ground (m)
H = effective stack height (m)
u = wind speed (m/s)
𝜎𝑦 and 𝜎𝑧 are plume standard deviation in the y and z directions (m)
Where atmospheric stability is chosen from A- very unstable, B- somewhat unstable, C-Neutral, D- somewhat stable, F- Very stable

5. Air quality modelling study to analyse the impact
of the World Bank Emission Guidelines for thermal
power plants in Delhi ( Arun Kansal et.al )
• Delhi is one the most polluted cities in the world due to its unrestricted growth. Urban
transport, manufacturing industries and thermal power plants are the major sources of
anthropogenic pollution.
• The World Bank (WB) has propose some environmental Guidelines for the TPPs in 1998
as a part of its pollution prevention and abatement handbook.
• The present study analyses how the ambient air quality of Delhi would improve if the
WBEG for the TPPs were to be implemented.
• Performance was evaluated by comparing monthly estimated and observed concentrations
at seven receptor locations: -
i. Ashok Vihar v. Shahadara
ii. ITO vi. Sirifort
iii. Shazadabagh vii. Nizamuddin
iv. Janakpuri

6. • Emission from
TPPs
TPP
Temperature
(K)
Exit
Velocity
(m/s)
Stack
Height
(m)
TSP
(g/s)
S𝐎𝟐
(g/s)
N𝐎𝟐
(g/s)
Rajgha𝐭𝐚
366.4 4.0 160 22.3 73.2 21.5
IG𝐓𝒃 384.0 1.6 30 0.36 0.1 12.6
I𝐏𝐛 402.1 8.2 61 14.5 45.1 28.8
Badarpu𝐫𝒂
401.7 25.2 150 237.9 1233 405.4
Pragat𝐢𝐚
372.0 2.3 70 0.7 0.08 23.8
Average emission rates and characteristics of TPPs
a – average of 12 months of two stacks
b – average of 12 months of three stacks

7. • Emission from
Industries
Industrial
Area
Temp.
(K)
Exit
Velocity
(m/s)
Stack
Diameter
(m)
TSP
(g/s)
S𝐎𝟐
(g/s)
N𝐎𝟐
(g/s)
Okhla Ph I 356 7 1.2 0.21 0.08 0.04
Okhla Ph II 352 5 1.1 0.11 0.05 0.03
Okhla Ph III 357 4 1.4 0.16 0.05 0.03
Smaipur 346 7 0.9 0.11 0.03 0.02
Badli 345 6 1.4 0.32 0.10 0.06
Udyog Nagar 367 5 0.8 0.06 0.03 0.01
Zakhira 341 8 0.7 0.09 0.02 0.01
Shazadabagh 350 6 0.6 0.04 0.02 0.01
Jhilmil 353 8 1.0 0.19 0.08 0.05
Najafgarh 341 7 1.1 0.15 0.05 0.03
Nangloi 352 6 0.8 0.06 0.02 0.01
Naraina 343 5 1.3 0.20 0.07 0.02
Wazirpur 354 4 2.2 0.42 0.15 0.06
S.M.A. 340 8 0.7 0.06 0.03 0.02

8. • Emission from
Vehicles
Receptor Station TSP S𝐎𝟐 N𝐎𝟐
ITO 33.4 0.42 8.60
Shazadabagh 8.80 0.04 2.60
Janakpuri 6.4 0.50 2.60
Ashok Vihar 2.5 0.10 2.10
Shahadara 24.4 1.15 7.60
Sirifort 21.9 0.12 7.70
Nizamuddin 14.1 0.04 6.70
Pollutant emissions (g/s) from roads

9. Indian and the WBEG for TPPs

10. Result
s
Average annual GLCs (μg/m3) of pollutants at CPCB air quality Monitoring stations in Delhi
Receptor
Stations
Indian Scenario WBEG Scenario
Percent
Reduction
TSP SO2 NO2 TSP SO2 NO2 TSP SO2 NO2
ITO 63.8 6.3 10.8 20.6 6.1 7.6 67.8 2.1 8.1
Shazadabagh 120.6 7.6 3.4 14.0 6.7 3.1 88.4 11.4 10.3
Janakpuri 57.8 2.9 3.2 9.3 2.7 2.6 83.9 6.6 17.8
Ashok Vihar 125.7 9.3 4.2 14.5 7.8 3.5 88.4 16.7 15.7
Shahadara 22.8 1.6 0.7 4.6 1.6 0.7 79.8 2.4 6.9
Sirifort 110.5 6.3 2.8 14.5 5.6 2.5 86.9 11.0 11.0
Nizamuddin 168.1 19.2 11.0 27 17.2 9.2 83.9 10.0 16.6
Impact of WBEG on air quality of Delhi

11. Conclusio
n
• The implementation of WBEG shows a significant reduction in TSP concentrations.
• Impact of WBEG on SO2 levels is not significant, since the Indian coal has already
lower sulphur content, and the current emissions are not affected significantly under
the WBEG scenario.
• The significant reduction in TSP emissions under the WBEG Scenario from theTPPs
is noteworthy.

12. Air Dispersion Modeling: Using SCREEN3
to Determine the MAGLC of Air Toxics
( Mario G. Cora et.al )
• The default hourly concentration estimate incorporated in the SCREEN3 program is based on one-hour
averaging.
3-hour: Multiply by 0.90
8-hour: Multiply by 0.70
24-hour: Multiply by 0.40
Annual: Multiply by 0.08
• MAGLC is the abbreviation for “maximum allowable ground level concentration.
i. Determine if a TLV exists for the compound being modeled.
ii. Divide it by 10.
iii. Adjust the standard to account for the duration of the exposure
MAGLC = 4(TLV)/XY
• Receptor means a particular location at which the pollutant’s concentration is measured or estimated

13. Maximum concentration at simple terrain = 130.3 μg/m3
TLV = 300 μg/ m3(as per European Community 1992 (EU) )
MAGLC = 300/42 = 7.14 μg/ m3
MAGLC Calculation

14. References
• Kansal Arun, Khare Mukesh, Sharma Chandra Shekhar, 2011. Air quality modelling
study to analyse the impact of the World Bank Emission Guidelines for thermal power
plants in Delhi. Atmospheric Pollution Research, 99-105
• Cora Mario G. ,Hung Yung-Tse, Pagan-Rodriguez Doritza, 2003. Air Dispersion
Modeling: Using SCREEN3 to Determine the MAGLC of Air Toxics. Environmental
Quality Management, 67-79

15. Thank You