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Support Center for Regulatory Atmospheric Modeling (SCRAM)

Air Quality Dispersion Modeling - Screening Models

The models listed here are screening models that are usually applied before the refined air quality model to determine if refined modeling is needed. The models in this section include AERSCREEN, COMPLEX1, CTSCREEN, RTDM3.2, SCREEN3, TSCREEN, VALLEY, and VISCREEN.

Screening Models and Documentation
AERSCREEN
AERSCREEN is the recommended screening model based on AERMOD. The model will produce estimates of "worst-case" 1-hour concentrations for a single source, without the need for hourly meteorological data, and also includes conversion factors to estimate "worst-case" 3-hour, 8-hour, 24-hour, and annual concentrations. AERSCREEN is intended to produce concentration estimates that are equal to or greater than the estimates produced by AERMOD with a fully developed set of meteorological and terrain data, but the degree of conservatism will vary depending on the application.

AERSCREEN (Version 16216) code including the latest MAKEMET code (Version 16216) is provided below along with documentation and test cases. The MAKEMET program interfaces with AERSCREEN to generate a site-specific matrix of screening meteorological conditions based on user inputs for input into AERMOD.

Please note that before using AERSCREEN, users must have the latest AERMOD executable (09292 or later) as well as the AERMAP terrain preprocessor and BPIPPRM executables. These programs can be downloaded from the AERMOD Modeling System section.
Model Code
AERSCREEN code and executables (v21112) (ZIP)(926 KB, 04-22-2021)
MAKEMET code and executables (v21112) (ZIP)(479 KB, 04-22-2021)
Model Documentation

README (TXT)(2 KB, 12-01-2016)
User's Guide (PDF)(115 pp, 2.3 MB, 04-22-2021, 454-B-21-005)
Model change bulletin #7 - Version Date 21112 (TXT)(1 KB, 04-22-2021)
Model change bulletin #6 - Version Date 16216 (TXT)(1 KB, 12-01-2016)
Model change bulletin #5 - Version Date 15181 (TXT)(3 KB, 06-30-2015)
Model change bulletin #4 - Version Date 14147 (TXT)(1 KB, 05-27-2014)
Model change bulletin #3 - Version Date 11126 (TXT)(1 KB, 05-06-2011)
Model change bulletin #2 - Version Date 11076 (TXT)(1 KB, 03-17-2011)
Model change bulletin #1 - Version Date 11060 (TXT)(15 KB, 03-11-2011)
Key changes since Beta release (PDF)(1 pg, 127 KB, 03-11-2011)
Test Case (ZIP)(48.6 MB, 04-22-2021)

Clarification on AERSCREEN as Recommended Screening Model (PDF)(3 pp, 268 KB, 04-11-2011)

COMPLEX1
COMPLEX1 is a multiple point source screening technique with terrain adjustment that incorporates the plume impaction algorithm of the VALLEY model.
Model Code
Executable (ZIP)(129 KB, 04-26-1990)
Model Documentation
User's Guide is presently not available
Model Change Bulletin #3 - Version Date 92290 (TXT)(3 KB, 10-29-1992)
Model Change Bulletin #2 - Version Date 90095 (TXT)(5 KB, 04-26-1990)
Model Change Bulletin #1 - Version Date 86064 (TXT)(2 KB, 05-22-1989)
CTSCREEN
CTSCREEN is a Gaussian plume dispersion model designed as a screening technique for regulatory application to plume impaction assessments in complex terrain. CTSCREEN is a screening version of the CTDMPLUS model.
Model Code
Readme/Executable/Test Case and Source Codewith Extended Memory Executable (ZIP)(710 KB, 03-21-1994) 
Model Documentation
User's Guide (PDF)(53 pp, 344 KB, 10-01-1990, 600-8-90-087)
Supplement to User's Guide (PDF)(6 pp, 80 KB, 03-01-1993)
Report on Modifications to CTSCREEN and CTDMPLUS(31 pp, 170 KB, 03-01-1993)
Notes on Terrain Input to CTDMPLUS and CTSCREEN (TXT)(10 KB, 08-09-1993)
Model Change Bulletin #5 - Version Date 94111 (TXT)(2 KB, 03-21-1994)
Model Change Bulletin #4 - Version Date 93228 (TXT)(6 KB, 08-19-1993)
Model Change Bulletin #3 - Version Date 93076 (TXT)(8 KB, 03-18-1993)
Model Change Bulletin #2 - Version Date 91107 (TXT)(5 KB, 07-18-1991)
Model Change Bulletin #1 - Version Date 91051 (TXT)(2 KB, 03-28-1991)
Model Tutorial
Tutorial Documentation (ZIP) (155 KB, 07-07-1992)
Instructions for CTSCREEN Tutorial (TXT)(3 KB, 07-07-1992)
CTSCREEN Demonstration (ZIP)(320 KB, 06-25-1992)
CTSCREEN Model, File 1 (ZIP)(305 KB, 05-06-1991)
CTSCREEN Model, File 2 (ZIP)(329 KB, 05-13-1991)
Text editor file (ZIP)(48 KB, 05-19-1992)
Terrain data file (ZIP)(77 KB, 04-17-1991)
BUCKBERG Terrain data file (TXT)(3 KB, 07-07-1992)
ORIG Terrain data file (TXT)(3 KB, 07-07-1992)
CTDM Batch file (TXT)(23 KB, 07-07-1992)
RTDM3.2
Rough Terrain Diffusion Model (RTDM3.2) is a sequential Gaussian plume model designed to estimate ground-level concentrations in rough (or flat) terrain in the vicinity of one or more co-located point sources.
Model Code
Executable (ZIP)(106 KB, 08-14-1989)
Model Documentation
User's Guide (PDF)(156 pp, 3 MB, 07-01-1987)
Model Change Bulletin #2 - Version Date 89226 (TXT)(2 KB, 08-14-1989)
Model Change Bulletin #1 - Version Date 87307 (TXT)(2 KB, 05-22-1989)
SCREEN3
SCREEN3 is a single source Gaussian plume model which provides maximum ground-level concentrations for point, area, flare, and volume sources, as well as concentrations in the cavity zone, and concentrations due to inversion break-up and shoreline fumigation. SCREEN3 is a screening version of the ISC3 model.
Model Code
Readme/Code/Executable (ZIP)(669 KB, 02-12-2013)
Model Documentation
User's Guide (PDF)(68 pp, 715 KB, 09-01-1995, 454-B-95-004)
Model Change Bulletin #3 - Version Date 13043 (TXT)(4 KB, 02-12-2013)
Model Change Bulletin #2 - Version Date 96043 (TXT)(46 KB, 02-12-1996)
Model Change Bulletin #1 - Version Date 95250 (TXT)(1 KB, 09-18-1995)
TSCREEN
Toxics Screening Model (TSCREEN) is a Gaussian model that implements the procedures to correctly analyze toxic emissions and their subsequent dispersion from one of many different types of possible releases for superfund sites. It contains 3 models: SCREEN3, PUFF, and RVD (Relief Valve Discharge).
Model Code
Code/Executable/Test Case (ZIP)(1.6 MB, 09-17-1995)
Model Documentation

User's Guide (PDF)(46 pp, 161 KB, 07-01-1994, 454-B-94-023)
TSCREEN Workbooks (PDF)(257 pp, 5.5 MB, 12-01-1992, 454-R-92-024)
Model Change Bulletin #7 - Version Date 95260 (TXT)(2 KB, 09-17-1995)
Model Change Bulletin #6 - Version Date 94133 (TXT)(7 KB, 05-13-1994)
Model Change Bulletin #5 - Version Date 92334 (TXT)(1 KB, 11-29-1992)
Model Change Bulletin #4 - Version Date 91303 (TXT)(1 KB, 10-30-1991)
Model Change Bulletin #3 - Version Date 91098 (TXT)(7 KB, 04-08-1991)
Model Change Bulletin #2 - Version Date 91070 (TXT)(3 KB, 03-11-1991)
Model Change Bulletin #1 - Version Date 91011 (TXT)(3 KB, 02-19-1991)

Model Tutorial
Tutorial Documentation (ZIP)(86 KB, 07-01-1992)
Instructions for TSCREEN Tutorial (TXT)(2 KB, 07-01-1992)
TSCREEN Demonstration (ZIP)(579 KB, 07-01-1992)
TSCREEN Model, File 1 (ZIP)(253 KB, 10-31-1991)
TSCREEN Model, File 2 (ZIP)(382 KB, 10-31-1991)
TSCREEN Model, File 3 (ZIP)(586 KB, 10-31-1991)
VALLEY
VALLEY is a steady-state, complex terrain, univariate Gaussian plume dispersion algorithm designed for estimating either 24-hour or annual concentrations resulting from emissions from up to 50 (total) point and area sources.
Model Code
Code (ZIP)(76 KB, 05-22-1989)
Model Documentation
User's Guide is available from NTIS (TXT)(18 KB, 05-22-1989)
Model Change Bulletin #1 - Version Date 85338(TXT)(2 KB, 05-22-1989)
VISCREEN
VISCREEN calculates the potential impact of a plume of specified emissions for specific transport and dispersion conditions.
Model Code
Executable (ZIP)(211 KB, 07-09-2013)
Model Documentation

VISCREEN Readme File (TXT)(3 KB, 07-09-2013)
Users Guide (PDF)(154 pp, 4.3 MB, 10-01-1992, 450-R-92-023)
User's Guide Update Pages (PDF)(51 pp, 98 KB, 10-01-1992, 450-R-92-023)
Model Change Bulletin #2 - Version Date 13190 (TXT)(2 KB, 07-09-2013)
Model Change Bulletin #1 - Version Date 88341 (TXT)(1 KB, 05-22-1989)

All VISCREEN Model Documentation Listed Above (ZIP)(4.2 MB, 08-15-2013)

Model Tutorial
Tutorial Documentation (ZIP)(2.9 MB, 07-09-2013)
VISCREEN Excel Spreadsheet
VISCREEN Excel Spreadsheet (ZIP)(193 KB, 07-09-2013)
Testcase
VISCREEN Testcase (ZIP)(17 KB, 07-09-2013)

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