Instruction on AERSCREEN

——A screening mode for AERMOD

Jun Wang

03/24/2011

AERSCREEN Tutorial

A Brief Outline• AERMOD/AERSCREEN history• AERSCREEN overview• AERSCREEN features• Installation• User interface• Example run

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AERSCREEN Tutorial

AERMOD/AERSCREEN History• AERMOD

– Initially developed in 1991, release in 2000, adopted in 2005.

• Point, area, volume Sources • Simple or complex terrain• Transport distance up to 50 km

– SCREEN option added to AERMOD in 1995 forces model to calculate centerline concentration for each source/receptor/meteorology combination.

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AERSCREEN Tutorial

AERMOD/AERSCREEN History• AERSCREEN

– Initially developed by Jim Haywood, Michigan DEQ– Draft submitted to EPA 4/25/06 (Alpha)– Release to public (Beta)– Latest version 11076 was released on 03/17/11

• MAKEMET, BPIPPRM and AERMAP to generate necessary AERMOD inputs.

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AERSCREEN Tutorial

Overview of AERSCREEN• MAKEMET program generates matrix of

meteorological conditions based on user-specified surface characteristics, formatted for input to AERMOD (.sfc and .pfl files)

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AERSCREEN Tutorial

Overview of AERSCREEN• Components of AERSCREEN

– AERSCREEN main program– MAKEMET– BPIPPRPM– AERMAP

• Running screen mode in two ways– Run AERSCREEN alone– Run AERMOD with screening option based on

MAKMETWill the two results same?

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Comparing to SCREEN3

AERSCREEN Tutorial

Overview of AERSCREEN• Source type:

– Single point source(vertical uncapped stack)– Capped stack– Horizontal stack– Rectangular area or circular area– Flare– Volume source

• Routine to find maximum concentration for automatic receptor distances

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AERSCREEN Tutorial

Overview of AERSCREEN• Data entered via prompts or by input file• No deposition• MAKEMET meteorology

– Internal matrices of other meteorological parameters

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AERSCREEN Tutorial

Overview of AERSCREEN• Data required

– Source parameters– Building downwash parameters– NOX to NO2 conversion– AERMAP (Terrain heights)– MAKEMET

• Ambient minimum and maximum temperatures• Minimum wind speed and anemometer height• Surface characteristic (albedo, Bowen ratio, roughness)

– Probe distance– Urban(population)/Rural– Flagpole receptor or discrete receptor (up to 10)

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AERSCREEN Tutorial

Overview of AERSCREEN• DEM File

– Suggest use AERMOD view to generate *.DEM file– Download from AERMOD view, find it at cache file

folder– Create demlist.txt

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AERSCREEN Tutorial

Overview of AERSCREEN• Discrete receptor file

– A txt file

Discrete receptors can be up to 10. 3/24/2011Page 11

AERSCREEN Tutorial

Overview of AERSCREEN• Average time factor

– Based on the upper bound of SCREEN3

– No annually average for area source3/24/2011Page 12

3 hour 1.0 (0.90+0.10)8 hour 0.9 (0.70+0.20)24 hour 0.6 (0.40+0.20)Annually 0.1 (0.08+0.02)

AERSCREEN Tutorial

Overview of AERSCREEN

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Figure 1: AERSCREEN Averaging Period Ratios vs. Plume Height(line shows 95th-percentile and error bars show 90th and 98th percentiles)

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0 50 100 150 200

3-hr8-hr24-hrAnnual

SCREEN 3-hr

SCREEN 8-hr

SCREEN 24-hr

SCREEN Ann

James Thurman, 2006

AERSCREEN Tutorial

Overview of AERSCREEN• MAKEMET

– Default value: min wind speed 0.5 m/sAnemometer height 10 mSingle wind direction 270 deg

– User-specified surface characteristics – albedo, Bowen ratio, and surface roughness

– Use seasonally varying surface characteristics for generic land use classifications. (AERSURFACE)

– Input an external file (AERMET Stage 3)

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AERSCREEN Tutorial

Overview of AERSCREEN• MAKEMET

– Looping through• Wind speeds• Cloud covers• Ambient temperatures• Solar elevation angles• Convective velocity scales

– Result• Friction velocity (U*)• Monin-Obukhov length (L)• Zim

• Zic and w* for convective case

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AERSCREEN Tutorial

AERSCREEN Features• All the input will go to AERSCREEN.INP• No necessary building downwash for area and

volume source.• Zero or negative stack temperature will treat

as temperature difference

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AERSCREEN Tutorial

AERSCREEN Features• Point, capped stacks and horizontal stack

sources– Emission rate (lb/hr or g/s) – Stack height (feet or meters) – Stack diameter (inches or meters) – Stack temperature (degrees Fahrenheit or Kelvin) – Stack velocity (ft/s or m/s) or flow rate (ACFM)

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AERSCREEN Tutorial

AERSCREEN Features• Flare source

– Emission rate (lb/hr or g/s) – Stack height (feet or meters) – Total heat release rate (cal/sec) – Radiative heat loss fraction

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AERSCREEN Tutorial

AERSCREEN Features• Volume source

– Emission rate (lb/hr or g/s)– Release height, i.e. center of volume (feet or meters)– Initial lateral dimension of the volume (feet or

meters)– Initial vertical dimension of the volume (feet or

meters)

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AERSCREEN Tutorial

AERSCREEN Features• Rectangular/Circular area source

– Emission rate (lb/hr or g/s) – Release height above ground (feet or meters) – Long and short dimensions of area (feet or meters)

orRadius of circle (feet or meters)

– Initial vertical dimension of plume (feet or meters)

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AERSCREEN Tutorial

AERSCREEN Features• NOx to NO2 conversion

– Ozone Limiting Method (OLM)– Plume Volume Molar Ratio Method (PVMRM)

• Input– NOx/NO2 in stack ratio– Background ozone concentration

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AERSCREEN Tutorial

AERSCREEN Features• Building downwash

– Building height (feet or meters) – Maximum building horizontal dimension (feet or

meters) – Minimum building horizontal dimension (feet or

meters) – Degrees from North of maximum building horizontal

dimension (0-179 degrees) – Degrees from North of stack location relative to

building center (0-360 degrees) – Distance between stack and building center (feet or

meters)

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AERSCREEN Tutorial

AERSCREEN Features

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AERSCREEN Tutorial

AERSCREEN Features• Meteorology and surface characteristics

– Minimum and maximum ambient air temperatures (Fahrenheit or Kelvin)

– Minimum wind speed (m/s) – Anemometer height (m) – Surface characteristics type (user-entered, AERMET

tables, or surface characteristics listed in an external file)

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AERSCREEN Tutorial

AERSCREEN Features• Terrain

– Probe distance (meters)– Discrete receptor distances – Flagpole receptors – Source elevation or use AERMAP to determine source

elevation – Source coordinates (geographic or UTM)– NAD datum (NAD 27 or 83) – UTM zone– Urban/Rual– Minimum ambient distance

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AERSCREEN Tutorial

AERSCREEN Features• Output

– AERSCREEN.OUT– max_conc_distance.txt,

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AERSCREEN Tutorial

Installation• Download from

– http://www.epa.gov/scram001/dispersion_screening.htm

• Extract AERSCREEN, MAKEMET, AERMOD, AERMAP, BPIPRPM in same directory

• Or simply download from– http://plaza.ufl.edu/j.wang/aerscreen.zip– Extract and go

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AERSCREEN Tutorial

User interface

– Windows interface available• $370~$450

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AERSCREEN Tutorial

Example run • See handout and screen.

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AERSCREEN Tutorial

Summary• What is the component of AERMOD family?

(except AERMOD itself)

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AERSCREEN Tutorial

Thanks!

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