air pollution control for environmental socity

1. Chapter 5.
Air Pollution Meteorology
VALLURI MAHENDRA
Asst. Prof.

2. 22.12.2023 S. Demir 2
Outline
 Introduction
 Solar Radiation
 Atmospheric Pressure
 Lapse rate & Potential Temperature
 Atmospheric Stability
 Coriolis Force & Gravitational Force
 Pressure Gradient Force
 Overall Atmospheric Motion
 Equations of Motion
 Wind Speed Profile

3. 22.12.2023 S. Demir 3
Introduction (1/2)
 Air pollutant cycle
 Emission
 Transport, diffusion, and transformation
 Deposition
 Re-insertion
 In large urban areas, there are several concentrated
pollutant sources
 All sources contribute to pollution at any specific site
 Determined by mainly meteorological conditions
 Dispersion patterns must be established
 Need for mathematical models and meteorological input data
for models

4. 22.12.2023 S. Demir 4
Introduction (2/2)
 Three dominant dispersion mechanisms
 General mean air motion that transport pollutants downwind
 Turbulent velocity fluctuations that disperse pollutants in all
directions
 Diffusion due to concentration gradients
 This chapter is devoted to meteorological fundamentals for
air pollution modelling

5. 22.12.2023 S. Demir 5
Solar Radiation (1/6)
 Solar constant  8.16 J/cm2.min
 0.4-0.8 µ  visible range, maximum intensity
Ref:
http://www.globalwarmingart.com/image
s/4/4c/Solar_Spectrum.png

6. 22.12.2023 S. Demir 6
Solar Radiation (2/6)
 Distribution of solar energy on earth
Ref: OpenLearn Web Site,
http://openlearn.open.ac.uk/file.php/1697/t206b1c01f26.jpg

7. 22.12.2023 S. Demir 7
Solar Radiation (3/6)
 At right angle on June, 21  Tropic of cancer
 At right angle on December, 21  Tropic of capricorn
 At right angle on March, 21 and september, 21  Equator
http://upload.wikimedia.org/wikipedia/commons/8/84/Earth-lighting-equinox_EN.png

8. 22.12.2023 S. Demir 8
Solar Radiation (4/6)
 Example: What is the Sun’s angle over Istanbul on June, 21? Note
that Istanbul is located on 40° N latitude.
 Solution: Sunlight reaches Tropic of Cancer (23° 27′) at right angle
on June, 21.
Where
θ = Sun’s angle at the given latitude
L2 = Latitude of given region
L1 = Latitude of region where sunlight reaches surface at right
angle
 
1
2
90 L
L 

 

  '
'
27
73
27
23
40
90 









9. 22.12.2023 S. Demir 9
Solar Radiation (5/6)
 Example: What is the Sun’s angle over a city located on 39° N
latitude when the sunlight reaches surface at right angle on 21° S
latitude?
 Solution:
 
 
  




30
21
39
90
90 1
2









 L
L

10. 22.12.2023 S. Demir 10
Solar Radiation (6/6)
 Homework (due 18.04.2008)
 Make a brief research on Stefan-Boltzman Law and write a one
page report for your research.
 Comment on what would happen if earth’s inclination were 24°
instead of 23°27′.
 What determines the seasons? Why some regions of earth get
warmer than other regions.
 Calculate the sunlight angle over Istanbul
 on March, 21
 on June, 21
 on September, 21
 on December, 21

11. 22.12.2023 S. Demir 11
Atmospheric Pressure (1/4)
 Force on earth surface due to the weight of the atmosphere
 Defined as force exerted per unit surface area
 Units of measurement  Pascal (Pa), atmospheric pressure
unit (apu, atm), newtons per meter-squared (N/m2), water
column (m H2O), etc.
 1 atm = 101325 Pa
 1 atm = 10.33 m H2O
 1 atm = 760 mm Hg
 1 Pa = 1 N/m2
 Atmospheric pressure at sea level is 1 atm

12. 22.12.2023 S. Demir 12
Atmospheric Pressure (2/4)
 Consider a stationary air parcel as shown
 Force balance (assuming no horizontal
pressure gradient)
 
 
 
 
g
dh
dP
g
h
P
g
h
P
h
g
P
h
gA
hA
g
Vg
mg
P
A
mg
PA
A
P
P
G
A
P
P
A
P
F
F
h
h
Net






























































0
0
lim
lim
0





13. 22.12.2023 S. Demir 13
Atmospheric Pressure (3/4)
 Integrating from h = z0 to h = z produces
 
 
     























0
0 exp
;
0
0
z
z
g
RT
M
z
P
z
P
gdh
RT
M
P
dP
gdh
RT
M
P
dP
g
RT
PM
dh
dP
RT
PM
g
dh
dP
A
z
z
A
z
P
z
P
A
A
A



14. 22.12.2023 S. Demir 14
Atmospheric Pressure (4/4)
 Homework (due 18.04.2008)
 Make a research about pressure measurement devices and
prepare a one-page report for your research. Give brief
explanations for each type.
 Calculate the atmospheric pressure on top of Everest if it is
1013 mb at sea level.

15. 22.12.2023 S. Demir 15
Lapse Rate & Potential Temperature (1/5)
 Adiabatic  no heat exchange
with surroundings
 Consider an air parcel moving
upward so rapidly that it
experiences no heat exchange
with surrounding atmosphere
 Enthalpy change:
where
H1 = initial enthalpy of air parcel
H2 = final enthalpy of air parcel
U1 = initial internal energy
U2 = final internal energy
V1 = initial volume
V2 = final volume
1
2 H
H
H 



16. 22.12.2023 S. Demir 16
 Enthalpy change is a
function of only temperature
when pressure is constant
 Substituting differential
pressure as follows:
 Since the process is
adiabatic, no heat exchange
occurs
Lapse Rate & Potential Temperature (2/5)
 By enthalpy’s definition
 In infinitesimal expression
 Internal energy substitution
 By internal energy definition
   
pV
U
H
pV
U
pV
U
H









 1
2
  pdV
Vdp
dU
pV
d
dU
dH 




  pdV
Vdp
W
Q
d
dH 



Vdp
dQ
pdV
Vdp
pdV
dQ
dH 





dT
C
Vdp
dQ
dH p



dT
C
gVdh
dQ p

 
m
C
C
gV
dh
dT
dT
C
gVdh
p
p
100
98
.
0











17. 22.12.2023 S. Demir 17
Lapse Rate & Potential Temperature (3/5)
 This approximation assumed there is no phase change in
the air parcel
 called Dry Adiabatic Lapse Rate (DALR)
 If any phase change takes place during the motion, the
temperature change will be far more different from DALR
 Called Saturated (Wet) Adiabatic Lapse Rate (SALR, WALR)
 Variable, must be calculated for each case
 Also significant in some cases; this course does not focus on it
 For standardization purposes, Standard Lapse Rate (SLR),
also known as Normal Lapse Rate (NLR), has been defined
 On average, in middle latitude, temperature changes from 1°C
to -56.7°C
 SLR = -0.66°C/100 m

18. 22.12.2023 S. Demir 18
Lapse Rate & Potential Temperature (4/5)
 Lapse rate measurements are taken by a device called
Radiosonde
 Results of measurements are plotted to obtain Environmental
Lapse Rate (ELR)
 ELR is real atmospheric lapse rate
 Another significant concept is Potential Temperature
 Defined as possible ground level temperature of an air parcel at
a given altitude
  H
DALR
T
Tp *




where
θ = Tp = potential temperature of air parcel
T = Temperature of air parcel
H = Height of air parcel from ground
DALR = Dry adiabatic lapse rate

19. 22.12.2023 S. Demir 19
Lapse Rate & Potential Temperature (5/5)
 Homework (due 18.04.2008)
 Calculate potential temperature for given data
 Calculate the atmospheric temperature at 800 m from the
ground if the atmosphere shows adiabatic characteristic and
the ground level temperature is 12°C.
Height, m Temperature, °C
350 8
750 2
1200 14

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Atmospheric Stability (4/8)
 Subadiabatic

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Atmospheric Stability (5/8)
 Inversion

22. 22.12.2023 S. Demir 22
Atmospheric Stability (7/8)
 Example: Calculate vertical temperature gradient and comment on
atmospheric stability condition if the atmospheric temperature at
835 m is 12 °C when the ground temperature is 25 °C.
 Solution:
The atmosphere is said to be unstable since ELR < DALR
m
C
m
C
m
C
z
T
T
dz
dT
ELR
ground
aloft
100
56
.
1
0156
.
0
0
835
25
12 














23. 22.12.2023 S. Demir 23
Atmospheric Stability (8/8)
 Homework (due 25.04.2008)
 Following measurements are taken over Istanbul at different
times. Determine atmospheric stability condition for each case.
 Briefly explain stable air, unstable air, neutral air and inversion.
 Make a brief research about the role of atmospheric stability in
dispersion of pollutants in the atmosphere and prepare a-one-
page report for your research.
 What is conditional stability? Explain.
Height,
m
Temperature, °C
Case 1 Case 2 Case 3 Case 4
0 14 22 17 4
1000 8 8 7 6

24. 22.12.2023 S. Demir 24
Coriolis Force
 “The Coriolis effect is an apparent deflection
of moving objects from a straight path when
they are viewed from a rotating frame of
reference. Coriolis effect is caused by the
Coriolis force, which appears in the equation
of motion of an object in a rotating frame of
reference.” (Wikipedia Web Site,
http://en.wikipedia.org/wiki/Coriolis_Force)
 
 











x
v
m
F
f
x
v
m
F
Coriolis
coriolis
Coriolis
2
2

25. 22.12.2023 S. Demir 25
Gravitational Force (3/3)
 Homework (due 25.04.2008)
 Determine the acceleration of an object near the Martian surface
due to gravitational attraction force
 Determine the acceleration of an object near the Moon’s surface
due to gravitational attraction force

26. THANK YOU
22.12.2023 S. Demir 26