Adiabatic - No exchange of heat of the parcel of air under consideration with the outside air. Superadiabatic, Strong, Unstable Temperature Reduction > 1 oC/100m Subadiabatic, Weak, Stable Temperature Reduction < 1 oC/100m Neutral Temperature Reduction = 1 oC/100m Inversion (Extreme Subadiabatic) Temperature Increase with Height

1. CEE 1503
Air Pollution
Meteorology and Control
Spring, 2005

2. Meteorology of Air Pollutants

3. Wind Rose
A Graphical
Picture of
The Direction
And Velocity
From Which
The Wind
Came

4. Pollution Rose
A Graphical
Picture of
The Direction
And
Magnitude
From Which
The Pollution
Came
Which Plant
Is the
Offending
Plant ?
Plant
Number 3

5. Lapse Rate
Temperature Change With Height

6. Adiabatic
No exchange of heat of the parcel of air
under consideration with the outside air.

7. Given a Known Volume of Air
As the above parcel of air rises,
it experiences less and less pressure
Ideal Gas Law:
PV = nRT
Since the volume stays the same,
the reduction of pressure corresponds to a
lowering of the temperature of the known volume of air.

8. Dry Adiabatic Lapse Rate
The rate at which non-moist air cools as it rises.
Calculated to Be:
-9.8 oC/km = -5.4 oF/1000 ft = -1 oC/100m
The actual temperature change of the air with
height is the Prevailing Lapse Rate

9. Lapse Rates
T
T - 1
100 m
Elevation
(m)
Temperature (oC)
Dry Adiabatic Lapse Rate

10. Lapse Rates
• Superadiabatic, Strong, Unstable
– Temperature Reduction > 1 oC/100m
• Subadiabatic, Weak, Stable
– Temperature Reduction < 1 oC/100m
• Neutral
– Temperature Reduction = 1 oC/100m
• Inversion (Extreme Subadiabatic)
– Temperature Increase with Height

11. Lapse Rates and
Atmospheric Stability

12. Atmospheric Stability
Superadiabatic – Strong Lapse Rate
Unstable Conditions

13. Atmospheric Stability
Subadiabatic – Weak Lapse Rate
Stable Conditions

14. Lapse Rates and Their
Effect on Smokestack
Plume Shapes

15. Lapse Rates and Atmospheric Stability
Strong Lapse Condition (Looping)
Wind

16. Lapse Rates and Atmospheric Stability
Weak Lapse Condition (Coning)
Wind

17. Lapse Rates and Atmospheric Stability
Inversion Condition (Fanning)
Wind

18. Lapse Rates and Atmospheric Stability
Inversion Below, Lapse Aloft (Lofting)
Wind

19. Lapse Rates and Atmospheric Stability
Weak Lapse Below, Inversion Aloft
(Trapping)
Wind

20. Lapse Rates and Atmospheric Stability

21. Actual Temperature Sounding

22. Dispersion Modeling
Predicting Air Pollutant Concentrations
Or
Air Pollution Control by Dilution

23. Gaussian Dispersion Model

24. Atmospheric Dispersion Model
• A very simple model based upon Gaussian
diffusion equations
• This type of model is used to model the
atmospheric dispersion of:
– A pulse release in three-dimensions
– A steady-state plume from a continuous source in two-
dimensions.

25. Dispersion Model Assumptions
• The predominant force is the wind.
• The greatest concentration of the pollutant
molecules is along the plume centerline.
• The process is a steady state process.

26. Dispersion Model Construction
• Plume travels horizontally in x-direction
• Plume disperses horizontally (y) and vertically (z)
• Concentration inside the plume follows Gaussian
Distribution
• Concentration (C(x,y,z)) is proportional to:
– Source strength (Q)
– Inverse of wind speed (1/U)
– Normalized Gaussian distribution function in the y and z directions
that is dependent on weather conditions

27. Plume Dispersion Coordinate System

28. Gaussian Function
G = A e
-0.5(y/y)2
Where,
y = the perpendicular distance from the
centerline of the plume
 y= Gaussian function in the y direction
where the standard deviation in the
y-direction will describe the dispersion
in the y-direction.

29. Gaussian Dispersion Model
C(x,y,z) = Gy Gz
Q
u
Note:
Atmospheric stability is classified in
categories A through F.

30. Atmospheric Stability Categories
• A&B = Superadiabatic
• C = Neutral
• D = Subadiabatic
• E = Weak inversion
• F = Strong inversion

31. Key to Stability Categories

32. Horizontal Dispersion Coefficients

33. Vertical Dispersion Coefficients

34. Effective Stack Height
ON BOARD

35. Final Model Construction
ON BOARD

36. The Air Pollution Problem
Emission
Source
Atmosphere Receptors
Pollutants Mixing and Chemical
Transformation

37. Air Pollution Sampling
and Control

38. The Air Pollution Control System
Emission
Source
Source
Control
Atmosphere
Detector
Humans
Animals
Plants
Materials
Receptor
Control
Response
Response

39. Air Pollution Control Strategy
Comprehensive air
pollution control strategy
Long-term control Short-term control
Urban planning
and zoning
Rescheduling
of activities
Programmed
reduction of the
emissions
Rescheduling
of activities
Immediate
reduction in
emissions
Requirements for long-term planning
•Air quality objective
•Airshed model
•Survey of control techniques and their cost
•Meteorological probabilities
Requirements for real-time control
•Air quality objective
•Dynamic modeling
•Rapid communication
•Strict enforcement of measures

40. Cost and Damage of Air Pollution

41. Particle Sizes and Measurement
Techniques

42. High Volume Sampler

43. Cascade Impactor

44. Bubbler

45. Stack Sampling Train Schematic

46. Gas Sampling Equipment

47. Air Pollution Control Technologies
• Control of Particulate Emission
- Settling
- Cyclone separation
- Wet scrubbing
- Baghouse filtration
- Electrostatic precipitation
• Control of Vapor-phase Emissions
– Wet scrubbing
– Activated carbon adsorption
– Incineration

48. Gravity Settling Chamber

49. Cyclone

50. Cyclone

51. Wet Collectors

52. Wet Collectors

53. Lime/Limestone Slurry Scrubber System for SO2 Control
CaCO3 + SO2 + H2O  CaSO3 + CO2 + H2O
CaCO3 + 2SO2 + O2 + H2O  2CaSO4 + 2CO2 + 2H2O

54. Baghouse Filters

55. Fabric Filters - Baghouses

56. Fabric Filters - Baghouses

57. Principle of ESP Operation

58. Electrostatic Precipitator

59. Electrostatic Precipitators

60. Electrostatic Precipitators

61. Wet ESP
Leonard
W.
Casson,
Ph.D.,
P.E.,
DEE

62. Wet ESP

63. Activated Carbon Adsorber

64. Incinerator

65. Effectiveness of Particulate Control Technologies

66. Efficiency of Particulate Control Devices

67. Efficiency of Particulate Control Devices