AERMOD Air Dispersion Modeling Workshop-Lakes_AERMOD_Course_Slides.pdf

AERMOD Air Dispersion Modeling Workshop
Copyright 1996-2014 – Lakes Environmental Software - www.webLakes.com
1
AERMOD AIR DISPERSION MODELING WORKSHOP
© 1996–2014 Lakes Environmental Software
AERMOD Course
© Copyright 1996-2014 – Lakes Environmental Software 2
Acknowledgements
LaGa Systems Pvt Ltd
Nayudu S. Sunkaraa
www.lagasys.com

2
Polite Request
Set cell phone to vibrate
No cell phone rings
Take calls outside
Good Morning!
Instructors
Prof. Jesse Thé, Ph.D., P.Eng.
Cris Thé, M.A.Sc.
Introductions
Timeline
Printed slides are available at the end of your Course Notes

3
Introductions
Name/Company
Experience in Air Dispersion Modeling (ADM)
Expectations
Timeline – Day 1
Day 1 – Morning
Introductions
Physics of Air Dispersion
Break (10-min)
Met Preprocessing
Hands-On Met Preprocessing
Coordinate System Maps
Lunch Break (1-hour)

4
Timeline – Day 1
Day 1 - Afternoon
Hands-On BPIP
Hands-On AERMOD
Break (10-min)
Terrain Theory
Hands-On AERMAP
Interpreting Results
Puff versus Plume ADM
Timeline – Day 2
Day 2 – Morning
1st Day Review
Introduction to Turbulence
Break
Hands-On DIY Project
Special Topics

5
Timeline – Day 2
Day 2 – Afternoon
Detailed Project
Hands-On Detailed Project
Break
Multi-Chemical Runs
Hands-On
Wet and Dry Deposition
Closure
Objectives
The participant should:
Understand the basic principles of the
US EPA ADM – AERMOD.
Have a working knowledge of air
dispersion modeling by using various
models.

6
Objectives
Not to learn how to use an
AERMOD interface!!!
ADM Course Warning!

7
The Need for ADM
1. Permitting
2. Design of stacks
3. Design of APC equipment
4. “Culpability” analysis
5. Prediction of air quality
6. Selection of air monitoring sites
7. Evaluation of the impact of new
pollution sources
Warnings on the Use of ADM
Air dispersion is complex and models
cannot be used in all situations
Models are being used:
1. Out of their range of validity
2. Out of the scope for which it was
designed

8
ADM Concepts
Fate of Pollutants

9
Coordinate System
Stability Classes

10
Stability Classes
Pasquill Stability Classes
1 A Very Unstable
2 B Unstable
3 C Slightly Unstable
4 D Neutral
5 E Stable
6 F Very Stable
Dispersion Coefficients
Instantaneous
10 min average
Instantaneous
15-minute
average

11
Important Note
AERMOD does NOT use
Stability Classes!
Instability – Convection Cells
Unstable = Convective

12
Stability Classes - DALR
Dry Adiabatic Lapse Rate ~ -10˚C/km
Temperature (°C)
Height (km)
Mixing Height (MH)
Mixing Height (MH)
The height to which significant mixing
of added pollutants occurs within the
atmosphere Higher MH Lower MH
Unstable Air Stable Air
Summer Winter
Day Time Night Time

13
Mixing Height
Mixing Height Problems
1. LONDON, UK – 1952
12,000 deaths
2. DENORA, PA, USA – 1948
• 50 deaths in a 14,000 city – 5,000 sick.
3. WHO estimates 7,000,000 death / yearly
(www.airimpactct.org)

14
Met. Effect on Stack Plume
Brookhaven Experiment

15
Air Model - Example
A B
Which source has the higher Ground
Level Concentration (GLC)?
B A ?
Air Model – Example
Stack A: Height=50m, Temp=400K
A B

16
Air Model – Example
Stack B: Height=25m, Temp=450K
A B
Plume Rise

17
Plume Rise
Plume Rise

18
Building Downwash
Building Downwash
Cavity Length
Cavity Length
Reattach
Cavity
Length

19
Building Downwash
Building Downwash
Example

20
Building Downwash
L = Lesser of the BH or PBW
BH = Building Height
PBW = Projected Building Width
Structure Influence Zone (SIZ)
Building Downwash
5L Area of Influence

21
Physics of Deposition
Particle Information:
1. Diameter
2. Density
Particle Suspension
Drag C Area
D
≅ •
Weight g Volume
≅ • •
ρ
Concentration within a pollution
plume is reduced by two
mechanisms:
Dispersion
Depletion

22
Flat Elevated Terrain
Flat Terrain
Terrain heights at or below stack base
Elevated Terrain
Terrain heights exceed stack base but are below stack
height
Complex Terrain
Complex Terrain
Terrain heights exceed stack height

23
Gaussian Plume 1-Hr Average
Instantaneous
10 min average
Instantaneous
15-minute
average
15-minute
average
Z
X
Y
Plume Centerline
Y'
Z'
Gaussian Plume – 1Hr Average

24
Gaussian Plume Model
C ~ Q
C ~ 1/U
End of ADM Concepts
Any Questions
Instantaneous
15-minute
average
US EPA Fluid Modeling Facility

25
AERMOD
Modeling System
AERMOD Modeling System
1. U.S. EPA regulatory Gaussian plume
air dispersion model
2. For near-field impacts (50-km max)
3. Preferred model for complex terrain
4. Improved treatment of urban effects

26
Latest Version: 14 134
Year Julian Day
Previous Releases:
13350, 12345, 12060, 11353, 11103,
11059, 09292, 07026, 06341, 04300
ADM Flowchart

27
Levels of Models
Screening Models
Simple estimation of air quality
SCREEN3, AERSCREEN
Refined Models
Need more detailed and precise input
data, more specialized concentration
estimates
AERMOD, CALPUFF, SCIPUFF

28
ADM Software Modules
Application Description
AERMET View Meteorological preprocessor for AERMOD
AERMET
AERSURFACE, AERMINUTE
WRPLOT View Wind rose plots for AERMOD meteorological data
AERMOD View Source contribution
Building downwash
Terrain processing
Post-processing of results
AERMET
Meteorological Preprocessor

29
Wind Direction
Wind Direction/Angles
Blowing From Blowing To
North = 360˚ (0˚denotes calm wind)
South = 180˚
East = 90˚
West = 270˚
Met Preprocessor Computes:
1. Planetary boundary layer turbulence
2. Turbulence scaling parameters
AERMET

30
AERMET System
AERMET Surface Data
Acceptable Surface Formats:
1. SCRAM
2. CD-144
3. SAMSON
4. HUSWO
5. TD-3280
6. TD-3505 (ISHD): Reported in GMT
Notes: - Formats 1 to 5 are reported in local standard time
- Format 6 is the only format currently supported
by U.S. National Climatic Data Center (NCDC)

31
Hourly Surface Met Data
Minimum Parameters:
1. Year, Month, Day, Hour
2. Wind Speed
3. Wind Direction
4. Dry Bulb Temperature
5. Cloud Cover (tenths)
Hourly Surface Met Data
For Deposition Studies:
1. Station Pressure (1013.25mb
default)
2. Relative Humidity
3. Precipitation Amount (for Wet
Deposition)

32
AERMET Upper Air Data
Acceptable Upper Air Formats:
1. TD-6201 Fixed Block
2. TD-6201 Variable Block
3. FSL
All Reported in GMT
Upper Air Data
● Reported in GMT
● Need Adjustment to covert GMT to
Local Standard Time (LST)
● Adjustment = -(Time Zone)

33
Surface Characteristics
AERMET Surface Characteristics:
1. Albedo (r)
2. Bowen Ratio (BO)
3. Surface Roughness (zO)
Albedo (r)
Fraction of solar energy reflected
(0 to 1)
Noon time (normal incidence)
value used
Land Use /
Season
Albedo
(r)
Water/Summer 0.1
Snow/Winter 0.6

34
Bowen Ratio (Bo)
1. A measure of the dryness at the surface
2. Values varies by land-use, season, and
moisture conditions
3. “The Higher the Drier”
Land-Use Bowen Ratio (Bo)
Water 0.1
Desert 10
Surface Roughness (zo)
1. The height at which wind speed
approaches zero
2. Ranges from 0.001 to 1
Land-Use Surface Roughness (zo)
Water 0.001 m (1mm)
Urban 1.00 m

35
AERMET Sectors
Defining Sectors:
1. Define sectors around site or met
station?
2. 0.1 to 5 km from origin
3. Sectors no smaller than a 30 degrees
4. Weighted average of surface
characteristics by surface area within
each sector
Defining Sectors
Desert = Sector 7-210 deg
Water = Sector 210-7 deg

36
Surfaces Parameters
AERSURFACE

37
AERSURFACE
US EPA AERSURFACE Tool:
1. Released Jan/2008, updated Jan/2013
2. Calculates surface parameters from land
use files (USGS NLCD92 format)
3. USGS NLCD92 files available for download
for USA locations only
4. You can create your own NLCD92 land use
file using AERMET View Land Use
Creator.
AERSURFACE
1. Surface Roughness: inverse
distance weighted geometric mean
over 0.1 to 5km – direction specific
2. Bowen Ratio: geometric mean over
10km
3. Albedo: arithmetic mean over 10km

38
AERSURFACE Domains
10 km
10
km Surface
Roughness
Domain
(0.1 to 5 km)
Albedo/Bowen
Ratio Domain
(10x10 km)
Raleigh/Durham (RDU) airport located in North Carolina
(Source: US EPA AERSURFACE User’s Guide)
AERMET View
AERSURFACE Utility

39
Land Use Creator
Create your
own land use
file, in NLCD92
format, to be
used in
AERSURFACE.
“Tools | Land Use Creator” menu option
Instructor Demonstration

40
Hands-On BPIP
Objectives
1. Use AERMET
2. Enter Surface Upper Data
3. Work with AERSURFACE
4. Understand results
Hands-On AERMET
Follow Course Notes – Chapter 1
1. Start AERMET View
2. New Project Name:
Met_Terrain.amf
3. Save Project In:
C:Course_AERMODCase_TerrainMet
4. Data Files:
C:Course_AERMODCase_TerrainMet
40 min

41
AERMET Conclusion
Any questions about running
AERMET?
Review AERMET Output tomorrow
AERMET View Utilities:
Multi-Year Met Data File
Import Surface Data (Excel)
AERMET View Utility
Multi-Year Met Data File Utility

42
AERMET View Utility
Import Surface Data from Excel
Met Data Resources
Surface/Upper Air Met Data:
http://www.webMET.com
Hourly Surface Data (TD-3505 Format):
http://ftp3.ncdc.noaa.gov/pub/data/noaa/
Upper Air Data (FSL Format):
http://www.esrl.noaa.gov/raobs/

43
What is Representative?
Not just a function of proximity
Things to consider:
1. Terrain features (e.g. valleys)
2. Coastal effects
3. Urban effects
Not Representative!

44
Met Data - Problems
1. Representative met data is not
always available
2. Met stations are far away (25 km
to 100 km)
3. Met data gaps
4. Onsite met data not available
Met Data – Possible Solution
1. Use output from prognostic gridded
meteorological models (e.g., WRF)
2. MM5 (Mesoscale Model) or WRF
data already used with CALPUFF

45
Satellite Obs
“95% of data available to NWP comes
from satellites”
SCIENCE, Feb 26, 2010, VOL 327
Modeled Measured
WRPLOT View - Lakes Environmental Software
PROJECT NO.:
DATE:
11/2/2008
MODELER:
Meteor. Silvio de Oliveira.
COMPANY NAME:
LAKES ENVIRONMENTAL
SOFTWARE
COMMENTS:
WIND ROSE PLOT:
PECEM BEACH - CEARÁ - PRODUCED FROM MM5 DATA
ANUAL WIND ROSE
NORTH
SOUTH
WEST EAST
6%
12%
18%
24%
30%
DATA PERIOD:
2007
Jan 1 - Dec 31
00:00 - 23:00
WIND SPEED
(m/s)
= 11.1
8.8 - 11.1
5.7 - 8.8
3.6 - 5.7
2.1 - 3.6
0.5 - 2.1
Calms: 0.09%
AVG. WIND SPEED:
4.00 m/s
CALM WINDS:
0.09%
TOTAL COUNT:
8760 hrs.
DISPLAY:
Wind Speed
Direction (blowing from)

46
MM5 vs Met Station
12-Km MM5 Grid
Wind Speed: Model vs. Measured (Nov-Dec 2012)
0.0
5.0
10.0
15.0
20.0
25.0
30.0
35.0
40.0
45.0
50.0
0
45
90
135
180
225
270
315
360
405
450
495
540
585
630
675
720
765
810
855
900
945
990
1035
1080
1125
1170
1215
1260
1305
1350
1395
1440
Hour
Wind
Speed
(km/h)
Measured
Model
Wind Speed: Model vs. Measured (Nov-Dec 2012)
0.0
5.0
10.0
15.0
20.0
25.0
30.0
35.0
40.0
45.0
50.0
0
45
90
135
180
225
270
315
360
405
450
495
540
585
630
675
720
765
810
855
900
945
990
1035
1080
1125
1170
1215
1260
1305
1350
1395
1440
Hour
Wind
Speed
(km/h)
Measured
Model
Wind Direction: Model vs. Measured (Nov-Dec 2012)
0.0
50.0
100.0
150.0
200.0
250.0
300.0
350.0
400.0
0
46
92
138
184
230
276
322
368
414
460
506
552
598
644
690
736
782
828
874
920
966
1012
1058
1104
1150
1196
1242
1288
1334
1380
1426
Hour
Wind
Direction
Measured
Model
Wind Direction: Model vs. Measured (Nov-Dec 2012)
0.0
50.0
100.0
150.0
200.0
250.0
300.0
350.0
400.0
0
46
92
138
184
230
276
322
368
414
460
506
552
598
644
690
736
782
828
874
920
966
1012
1058
1104
1150
1196
1242
1288
1334
1380
1426
Hour
Wind
Direction
Measured
Model
Met Questions ?

47
Coordinate System
Maps
Maps
We use different kinds of Maps
1. Terrain maps
2. Land use maps
3. Base maps
We need coordinate systems for
these maps

48
Theory of the Globe
1. We live on a BALL!
2. We read from flat surfaces
3. We need to project GEODE
to a plane
Map Projections
Conical Projection:
Lambert Conic Conformal
(LCC)

49
UTM Coordinates
World UTM Zones
60 UTM Zones (1 to 60) – North and South

50
UTM Zones - India
UTM Zones
Source: Ryerson University
(http://www.ryerson.ca/madar/geospatial/internet/static/World_UTM_Map%5B1%5D.pdf)

51
Datum
A model of the shape of the Earth
1. WGS-84
2. NAD-83
3. NAD-27
4. GDA-94
5. Many others
Inconsistent datums can cause
errors up to 200m
Google Earth (GE)
Setting UTM Coordinates in GE
1
2
UTM Zone: 13 UTM Coordinates
Elevation: 1611m (MSL)
3

52
Supported Base Maps
Base Maps
DLG (USGS)
DXF (AutoCAD)
LULC (USGS)
MrSID
Raster Images (BMP, JPEG, TIFF, PNG,
GIF)
Shapefile (ArcView)
Tile Maps
Automated Download of
Geo-Referenced Base Maps
Satellite and Street Maps

53
Base Maps - Example
JPEG Maps from Google Earth
Note: See the Course CD for notes on how to create and
georeference a base map from Google Earth.
Mark coordinates
of 2 reference
points
Overlays / Layers
Overlay Control

54
Export to Google Earth
End of Mapping
Any Questions

55
BPIP
Building Downwash Analysis
BPIP
1. BPIP - Building Profile Input Program
2. Geometry for building downwash
3. Parameters: Point sources and building
locations/dimensions

56
Hands-On BPIP
Objectives
1. Use BPIP
2. Work with Maps
3. Enter Sources and Buildings
4. Understand BPIP results

57
1. Start AERMOD View
Case_Terrain.isc
3. Save Project In:
C:Course_AERMODCase_Terrain
4. Base Maps:
…Case_TerrainBase_Maps
Hands-On BPIP
30 min
BPIP Output
Building Heights
Building Widths
Building Lengths
Along Flow
Across Flow

58
BPIP Output Definitions
Area of Influence

59
AERMOD in 5 Minutes or Less!
Hands-On AERMOD
Objectives
1. Specify Pollutant
2. Specify Met Data
3. Specify Receptors
4. Run AERMOD Model
5. Post-Process AERMOD Results

60
2. Open project created in Chapter 2
Case_Terrain.isc
3. Project folder:
C:Course_AERMODCase_TerrainCase_Terrain
Hands-On AERMOD
30 min
Summary AERMOD
Met Data
Buildings
Sources
Receptors
Model
Run

61
AERMOD
Interpreting Results
Output Types
AERMOD Output Types:
1. Main Output file
2. Summary file
3. Plot file
4. Post file
5. Threshold violations
6. Others…
Use outputs appropriate for your
purpose

62
Main Output File
1. Automatically created
2. Contains input and output summaries
3. Lists errors and warnings
4. Contains optional output data tables
Summary File
1. Contains output summaries
2. Lists errors and warnings

63
Main Output File
Highest Values Table
1. Reports the nth highest concentration
at each receptor
2. n = 1 to 10 (specified by user)
Main Output File
Maximum Values Table
Reports the x highest concentrations,
at any receptor, at any time
x (specified by user)

64
Main Output File
Daily Values Table
Reports concentrations at each
receptor, day by day
A lot of data!
PLOTFILE
Plot Files
Used to create contours
Same data as highest
values table
Not a snapshot in time

65
MAXIFILE
Threshold Violation File
(MAXIFILE)
Lists all concentrations above a user
specified threshold
POSTFILE
POST File
Reports all concentrations at each
hour and at every receptor
Large Files!

66
Source Contributions
Source Groups
Identify the significant sources
Determine individual and group
contributions
Source Contributions
Using EVENT Model
1. Select EVENT option in Control Pathway
2. Run AERMOD (EVENT input file generated)
3. Run EVENT model
4. Review EVENT output file for source contributions

67
Determine Significant Factors
Downwash
Turn downwash on/off and rerun the
model to see the impact
Determine Significant Factors
Date and Time
Check the date/time maximums occur
Maximums occurring all at the same
time?
Maximums at different dates, but same
time of day?
Is a particular met condition to blame?
3D View
Are terrain features causing impacts?

68
Common Situations
No Concentration Around Source
Common Situations
Maximums not downwind in the
prevailing wind direction
Isolated low wind speed hours may be
causing your maximums

69
Common Situations
Zero Contours
Small concentrations need scientific
notation
End AERMOD Hands-On
Any Questions

70
AERMAP
Terrain Processing
AERMAP - Terrain Processor
Calculates:
1. Terrain Elevations for sources
and receptors
2. Hill Height Scale to determine
dividing streamline height

71
Terrain Interpolation
AERMOD Terrain Treatment
AERMOD uses the dividing
streamline height concept
Dividing
Streamline
Height

72
Dividing Streamline Height
In Stable Conditions:
If a “particle” of air has just enough kinetic
energy to reach the top of a hill (Froude No. =
1.0), it is at the dividing streamline height
If higher: goes over the hill
If lower: goes into or around the hill
Dividing Streamline Height
In Convective Conditions:
All flow is over the hill, as with
flow above the dividing
streamline height

73
Hill Height Effects
Mount Taranaki, New Zealand
Peak Elevation: 2,518 m
Plume goes around
the hill
Elevations vs Hill Heights
Mount Taranaki, New Zealand
Hill Heights (ZHILL)
Elevations (ZELEV)

74
AERMAP Domain
Select major hills surrounding
modeling domain
US EPA Model Evaluation
Using AERMAP hill height scale,
AERMOD is able to represent the effect
of terrain on concentration values.
US EPA Model Evaluation Results – Tracy data set, a
rural complex terrain site east of Reno, NV.

75
Terrain Processing
1. Click Terrain button
2. Select Map Type
3. Download Terrain Data
4. Process + Run AERMAP
Hands-On AERMAP
Objectives
1. Specify and process Terrain data
2. Use AERMOD with Terrain
3. Compare AERMOD results

76
2. Open project created in Chapter 2/3
Case_Terrain.isc
3. Project folder:
Hands-On AERMAP
30 min
Terrain Data Formats
United States:
USGS NED GeoTIFF (~30m, ~10m, ~3m)
USGS 7.5-Min DEM (~30m)
USGS 1-Deg DEM (~90m)
SRTM1 (~30m)
Canada:
15-Min DEM (CDED) (~60m)
International:
SRTM3 (~ 90m)
SRTM30 GTOPO30 (~900m)

77
http://www.webGIS.com
Where to Get SRTM / DEM?
Terrain Processing Conclusion
Analysis of results
Where to get terrain data…

78
Puff Vs Plume Models
Plume Limitations
Example: AERMOD
Steady-State
50 km domain
10 km/hr wind
Run AERMOD for 1 hour only

79
Homogeneous Wind Field
Plume Limitation
Plume

80
Puff Vs Plume
(CALPUFF, SCIPUFF)
Non Steady-State
(AERMOD)
Steady-State
PUFF Models
Example: CALPUFF
Simulates pollutant releases as a
series of puffs
U.S. EPA Regulatory Model
Simple 3-D “Diagnostic” Wind Field

81
CALPUFF View – Wind Field
Hour 1 (theta = 1800)

82

83

84
Puff “Memory”

85
CALPUFF vs AERMOD vs Monitor
NJDEP Martin Creek Evaluation
Brode_10thMC_CALPFUFF_Nearfield_Validation_03-13-2012.pdf
Puff Limitation

86
Lagrangian Particle Model
1. Prognostic
Wind Field
2. Multiple Met
Stations
3. 1,000 times
more resources
than Plume
Models
Lagrangian Particle Model
Example: AUSTAL2000

87
Conclusion Plume |Puff | Tracer
“Balancing Act” among approaches
Conclusion AERMOD – Day 1
Met
Files
Buildings Sources Receptors
Avg.
Periods
Run
AERMOD
Post-
Process

88
Day 1 - Concluded
Sleep early
Boost your caffeine in the morning
Get here before 9:00 am
AERMOD Course
Day 2

89
Polite Request
Set cell phone to vibrate
No cell phone rings
Take calls outside
Remember !!!

90
Timeline – Day 2
Day 2 – Morning
1st Day Review
Break
Hands-On DIY Project
Special Topics
Timeline – Day 2
Day 2 – Afternoon
Detailed Project
Break
Multi-Chemical Runs
Hands-On
Wet and Dry Deposition
Closure

91
Review – Day 1
Met
Files
Buildings Sources Receptors
Avg.
Periods
Run
AERMOD
Post-
Process
Review Concepts – Day 1
What is?
1. Stability Classes
2. Mixing Height
3. Building Downwash
4. Main Variables in Deposition
5. Meteorological Preprocessing
6. Terrain Preprocessing
5 MINUTES

92
Introduction to
Turbulence
1. Maybe your first introduction to
turbulence concepts
2. Don’t expect to understand it all
now

93
Fluid Shear Stress
= ∙

Characterizing Turbulence
Both Mechanical and Convective
turbulence are important for dispersion
1. Velocity scale
2. Length scale

94
What Do We Need?
Mechanical Velocity Scale
Convective Velocity Scale
Convective Length Scale
Mechanical Length Scale
Viscous Flow
(a)
(b)
(c)

95
The Reynolds Number
The Froude Number
Used in the treatment of terrain

96
Ground Heating
Net Solar Radiation
1. Solar Angle
2. Cloud Cover
3. Albedo

97
Solar Angle
Relevant Thermal Scale
T / g
ρ
ρ
ρ
ρ * Cp / H

98
Sensible Heat Flux (H)
Tsurface Tair
Tsurface Tair
Convective Velocity Scale (w*)
• w* ~ Convective eddies
• Zic = Convective mix height
• ρ = Air density
w*

99
Check List
w*
Surface Friction Velocity (u*)
1. Function of Kinetic Energy
and surface roughness
2. What is surface roughness?

100
Check List
w*
U*
L* = Monin-Obukhov Length [m]
k = Von Karman’s Constant [0.4]
u* = Friction Velocity [m/s]
Monin-Obukhov Length (L*)
∗ = −

∗

101
L* - Unstable Atmosphere
|L|
|L|
Slightly
Convective
[C]
Very
Convective
[A]
L* - Stable Atmosphere
|L|
|L|
Slightly
Stable
[E]
Very
Stable
[F]

102
Monin-Obukhov Length
Roughness [m] ~ L* [m] Stability Class
0.1 -12.5 A (Very Unstable)
-25 B (Unstable)
-65 C (Slightly Unstable)
-- D (Neutral)
+65 E (Stable)
+30 F (Very Stable)
Roughness [m] ~ L* [m] Stability Class
0.5 -16 A (Very Unstable)
-50 B (Unstable)
-100 C (Slightly Unstable)
-- D (Neutral)
+100 E (Stable)
+50 F (Very Stable)
Check List
w*
U*
L*
L*

103
Example use of L*, u*, and w*
Inspecting AERMET Output
Specifically the Surface Output File
(*.SFC)

104
Sensible Heat Flux and Monin-Obukhov Length
A Look at AERMET Output
[H] [L*]
A Look at AERMET Output
Surface Friction Velocity (u*) and Wind Speed
[U*] [W*]

105
Turbulent Profiles
Conclusions
Very complex
Not solved directly
Use “simplified” parameters
Understanding these parameters is a
major help to QA your modeling
results
AERMOD
Pathways

106
AERMOD Pathways
1. CO – Control
2. SO – Source
3. RE – Receptor
4. ME – Meteorology
5. OU – Output Options
--------------------------
6. BU – Building Inputs
7. TE – Terrain Processor
Control Pathway (CO)
1. Dispersion Options
2. Pollutant Type
3. Averaging Period

107
CO Pathway – Input File
1. Source Types and Locations
2. Release Parameters
3. Building Downwash Data
4. Background Concentrations
5. Source Groups
Source Pathway (SO)

108
SO Pathway – Input File
Receptor Pathway (RE)
1. Grids (Polar, Cartesian)
2. Discrete Receptors
3. Fenceline Receptors
4. Flagpole Receptors

109
RE Pathway – Input File
• 2 Met Files (*.SFC, *.PFL)
• Data Period to Process:
Entire or subset of the met data period
Meteorology Pathway (ME)

110
ME Pathway – Input File
1. Main Output File:Tabular outputs
2. Summary: Summary of high ranked values
3. PLOTFILE: Contour plot files
4. MAXIFILE: Threshold violation files
5. POSTFILE: Post-processing files
6. Others
Output Pathway (OU)

111
OU Pathway – Input File
Building Parameters
1. Tiers
2. Dimensions
3. Base Elevations
Building Pathway (BU)

112
Questions ?
Do-It-Yourself Project
(DIY)

113
Hands-On DIY
No Course Notes to Follow
1. Create new project: DIY.isc
2. Folder: …Course_AERMODCase_DIY
3. Met Files: …Case_DIYMet
4. Use projection: UTM – WGS84
5. Choose reference coordinates from
your facility
6. Choose suitable receptors
7. Flowchart in Quick Reference section
DIY – Building Layout

114
DIY – Project Parameters
Parameter Value
Pollutant CO
Averaging Time 1h, 24h, Period
Dispersion Option Rural
Met Station Base
Elevation
0 m
Stack Parameters
X: ?, Y: ? – Your UTM Coordinates
Base Elevation = 0m
Release Height = 80m
Emission Rate = 1g/s
Diameter = 4m
Exit Velocity = 14m/s
Exit Temp = 400K
Defining Receptors
1. Modeling Domain?
2. Receptor Spacing?
3. Number of Receptors?
4. Type of Receptors ?

115
Results for Different Grids
Max: 1.70 ug/m3
Max: 1.71 ug/m3
Cartesian Grid
Polar Grid
Plant Boundary Options
1. Enter Plant Boundary
2. Eliminate Receptors within Plant
Boundary
3. Add Fenceline Receptors
4. Re-Run Project

116
Plant Blanking Boundary
1. Hides contours
2. Calculations at receptors still occur
Conclusion
Questions?

117
Special Topics
Coastal Effects - Day
Migration
Warmer
Day Time/Summer

118
Coastal Effects - Night
Valley - Morning

119
Valley - Afternoon
Anthropogenic Heat Flux

120
Odor Unit (OU) based odor
threshold
Time averaging Gaussian
plume approx.
Odor Modeling
Cnew = Cold (Told / Tnew)q
C = concentration
T = averaging time
q = decay factor
Odor Units
Emission Output Unit

121
Concentration Converter
Convert 1-hour odor results into smaller
averaging periods (e.g., 10 min)
Odor Thresholds
Odorant Level
Acetic Acid 1. ppm
Acetone 100. ppm
Ammonia 1.5 ppm
H2S 0.5 (3) ppb
Phenol 50 ppb

122
AERMOD – Source Types
AERMOD Source Types:
1. POINT
2. VOLUME
3. AREA (rectangular, circular, polygonal)
4. OPEN PIT
5. LINE (modified area source)
Additional Source Types
Only in AERMOD View
1. FLARE
2. LINE
a. Line VOLUME (collection of volume
sources along a polyline)
b. Line AREA (collection of area
sources along a polyline)

123
POINT Sources
1. Pollutant release rate
(mass/time)
2. Stack location
3. Stack height and diameter
4. Stack gas temperature
and exit velocity
Examples: Stacks, chimneys, vents
VOLUME Sources
1. Pollutant release rate
(mass/time)
2. Location
3. Release height
4. Initial lateral and vertical
dimensions
Examples: building roof monitors, multiple
vents, conveyor belts, haul roads

124
AREA Sources
Area Sources: low level or ground level releases
with no plume rise (plume meander not
implemented)
1. Pollutant release rate (mass/time/area) [g/s/m2]
2. Release height
3. Location and dimensions
4. Initial plume vertical dimension (optional)
Examples: material storage
piles, forest fires, landfills,
waste lagoons
OPEN PIT Sources
Open Pit Sources: used to model particulate
emissions from open pits (no plume rise)
1. Pollutant release rate (mass/time/area)
2. Average release height,
3. Dimensions and volume,
4. Orientation angle
Examples: surface mines and
quarries

125
LINE Sources
Line Sources: Added in AERMOD 12345. Uses
identical routines as rectangular area sources.
Identified with start and end points as opposed to
X Y lengths.
1. Pollutant release rate (mass/time/area)
2. Release height
3. Width
4. Initial plume vertical dimension (optional)
LINE Sources
Represented by
Separated or
Adjacent Volume
Sources
Represented by
Area Sources
Examples: Roads, conveyor belts, rail
lines, haul roads

126
Stack Tip Downwash
Stack Tip Downwash
If Vs 1.5 Ws
FLARE Sources
Pseudo Point Source

127
Hr = Total heat release rate (J/s)
V = Volumetric flow rate to the flare (m3/s)
fi = Volume fraction of each gas component
Hi = Net heating value of each component
(J/g-mole)
Flares – US EPA Method
Hsl = Effective flare height (m)
Hs = Stack height above ground (m)
Hr = Total heat release rate (J/s)
Flares – US EPA Method

128
Flares - Alberta Method
The Flare spreadsheet from the
Energy Resources Conservation
Board (ERCB) of Alberta also
calculates flare point-source pseudo
parameters (ERCBflare.xls) .
Directive 060: Upstream Petroleum Industry
Flaring, Incinerating, and Venting
http://www.aer.ca/rules-and-
regulations/directives/directive-060
Capped Horizontal Stacks
Beta options available for
capped and horizontal releases
Use at your own risk

129
Emissions from Tanks
Evaporative Losses:
1. Breathing/standing storage losses:
Losses during storage
2. Working losses:
Losses during filling and emptying
operations
Tanks – Fixed Roof

130
Tanks – Floating Roof
Tanks – Buildings / Sources
Use the Circular Building tool to
draw each tank as a building.
Use the Point Source tool to specify
point sources on each tank according
to the schema shown on the next
slide.

131
Storage Tanks
Floating Roofs Fixed Roofs
8 point sources around the
perimeter of the tank
1 point source at the center
of the tank
Exit Velocity Stack Diameter Exit Temperature
Near zero
i.e. 0.001 m/s
Near zero
i.e. 0.001m
Ambient – 0.0 sets
models to use ambient
temperature
Example
Tanks with Fixed Roofs
Tanks with Floating Roofs

132
Variable Emissions
Conclusion
Questions?

133
NO2 Modeling Options
NO2 Chemistry
Day Time
NO2 + Light + O2 = NO + O3
Night Time
NO + O3 = NO2 + O2

134
3-Tier Approach – NO2
NO2 NAAQS
Modeling
Tier 1
100%
NOX to NO2
Tier 2
Ambient Ratio Method
(ARM)
Tier 3
OLM
PVMRM
3-Tier Approach – NO2
1. Tier 1 - Total conversion of NOX to NO2
2. Tier 2 - Ambient Ratio Method (ARM)
(0.80 is the recommended the ambient
ratio for the 1-hour NO2)
3. Tier 3 - OLM or PVMRM screening
methods using in-stack and equilibrium
NO2 / NOX ratios and background ozone
concentrations

135
OLM PVMRM
1. For OLM, must use OLM Group ALL for
combining plumes.
2. Default In-Stack NO2 / NOX Ratio = 0.5
can be used in the absence of more
detailed information.
3. PVMRM may not be as good as OLM for
low level sources.
NO2 Options: Default
Select Pollutant
NO2
Choose Tier 1 or
Tier 2 analysis

136
NO2 Options: Non-Default
Select Pollutant
NO2
Enable Non-Default
model option
Select desired tier
and modeling
option
Add background
ozone data for
Tier 3
AERMOD View - NO2 Options
Step 3:
If in USA:
Select the US EPA
1-HR NO2 NAAQS
Step 3:
If Outside USA:
Disable US NAAQS Special
Processing
Step 2: Averaging Period
Specify 1-Hour
Step 1: Pollutant
Select NO2

137
Detailed Project
The Task
1. You are a consultant for OilCo
Refineries.
2. You need to conduct an air
dispersion model for benzene.

138
Source Types Included
1. Furnaces, Boilers and Exhausts (point)
2. Tanks
3. Roads (line)
4. Fugitive release from pipes (volume)
AERMOD and Line Sources
1. Roads are line sources.
2. AERMOD does not model line sources
directly.
3. A line source can be approximated by
a series of volume or area sources.

139
Line Source Tools
Creates a series of volume or
area sources
Line Area
Sources
Line Volume
Sources
Mixing Zone
The width of the volume sources should
cover the road + 3m either side

140
Vertical Dimension
Vertical dimension: 1.7 x vehicle height
Typical heights:
Car: 1.5m x 1.7 = 2.55m
Truck: 3m x 1.7 = 5.1m
Note: 1.7 is the recommended factor in the Haul
Road Workgroup Final Report (March 2012)
available at SCRAM web site.
Initial Vertical Dimension
Initial Vertical Dimension = σz0
Vertical Dimension / 2.15 (surface-based)

141
Fugitive Releases
1. A network of pipes creates emissions
over a volume
2. Use volume sources
Sources
1. You can input them manually if you wish
2. They can also be imported from a partial
input file - OilCo_Sources.p1
3. C:Course_AERMODCase_OilCoOther

142
Objective
1. Work with:
a. Line Sources
b. Area Sources
c. Volume Sources
d. Source Groups
2. Import Sources
OilCo.isc
3. Save Project In:
C:Course_AERMODCase_OilCo
4. Data Files:
…Case_OilCoMet
…Case_OilCoBase_Maps
…Case_OilCoTerrain
30 min

143
Conclusion Oil Co
Questions?
Multi-Chem

144
Unit Emission Concept
Summation Concept

145
Multi-Chemical
Batcher

146
Multi-Chemical Run
Objective
Work with:
1. Multi-Chemical
2. Practice Options

147
Hands-On Multi-Chem
2. Open project created in Chapter 2/3:
Case_Terrain.isc
3. Project Location:
4. Use Multi-Chemical Utility
20 min
Multi-Chem Conclusion
Viewing results

148
Conclusion Multi-Chem
Questions?
Wet and Dry
Deposition

149
Particle Information:
Diameter
Density
Particle Suspension
Drag C Area
D
≅ •
Weight g Volume
≅ • •
ρ
Dry Wet Deposition

150
Deposition Data
SO Pathway – Gas Particle Data
Particle Size Distributions
US EPA AP-42: Appendix B.2
1. “Generic” particle size distributions
2. Examples:
Internal Combustion Engines
(Gasoline/Diesel Fuels)
External Combustion (Mixed Fuels)
Fugitive Aggregates, etc.

151
AP-42 Generic Distribution
Example: Exhaust Emissions (Tailpipe Emissions)
Source: AP-42, Appendix B.2, Table B.2.2
Calculated Mass Fractions for AERMOD
Deposition Flux
Deposition Unit: g/m2/year

152
Hands-On Deposition
2. Open Project Terrain.isc and Save As:
Depos.isc
3. Project Location:
C:Course_AERMODCase_Depos
4. Run AERMOD with Deposition options
20 min
Deposition Results

153
Deposition Conclusion
Questions?
Hands-On Mining Project
Rosemont.isc
3. Save Project In:
C:Course_AERMODCase_Mine
4. Data Files:
…Case_MineMet
…Case_MineTerrain
30 min

154
Hands-On Mining Project
Objectives
● Modeling mining operations
● Work with open pit, volume, and line
sources
Additional Course
Resources

155
Future Air Modeling Topics
Long Range Transport
CALPUFF SCIPUFF
AUSTAL2000 Particle Model
Risk Assessment
Human Health Risk
Ecological Risk
Residual Risk
ADM Resources
FREE MODELING RESOURCES
www.webMET.com www.webGIS.com
www.webLAKES.com

156
ADM Resources
US EPA SCRAM
www.epa.gov/scram001
Example Guidance
Ontario MOE Air Dispersion
Modelling Guidance
Prepared by Lakes Environmental
http://www.ene.gov.on.ca/publications/6830e.pdf
Helpful modeling
advice

157
Course Material
Course Notes
Case studies
Course CD
Case studies data files
Modeling resources
Screen View
WRPLOT View
Course Slides
Course Presentation:
Two color slides per page available in
the Course CD.

158
Closure
Thank You All !!!
Jesse L. Thé
Cris L. Thé
support@webLakes.com

AERMOD Air Dispersion Modeling Workshop-Lakes_AERMOD_Course_Slides.pdf

More Related Content

Similar to AERMOD Air Dispersion Modeling Workshop-Lakes_AERMOD_Course_Slides.pdf

More from Chemical Engineering Dept. NIT Rourkela-769008, Odisha, India

Recently uploaded

AERMOD Air Dispersion Modeling Workshop-Lakes_AERMOD_Course_Slides.pdf