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Technology Transfer Network Support Center for Regulatory Air Models |
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Dispersion Models
Please click on the appropriate area below
Preferred/Recommended Models
Note: To
view and access all available Model Change Bulletins, click
here.
Screening ToolsThis area
provides a list of screening tools that can be used preceeding a refined
modeling analysis. The screening tools listed in this section are:
Note:
To view and access all available Model Change Bulletins, click
here.
Alternative Models
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ADAM
(Air Force Dispersion Assessment Model) a modified box and
Gaussian dispersion model which incorporates
thermodynamics, chemistry, heat transfer, aerosol loading, and dense gas
effects. Release scenarios include continuous and instantaneous,
area and point, pressurized and unpressurized, and
liquid/vapor/two-phased options.
Executables --
(271KB,ZIP) |
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ADMS-3
(Atmospheric Dispersion Modeling System)
an advanced model for calculating concentrations of
pollutants emitted both continuously from point, line, volume and area
sources, or discretely from point sources. The model includes
algorithms which take account of the following: effects of main site
buiding; complex terrrain; wet deposition, gravitational settling and
dry deposition; short term fluctuations in concentration; chemical
reactions; radioactive decay and gamma-dose; plume rise as a function of
distance; jets and directional releases; averaging time ranging from
very short to annual; condensed plume visibility; meteorological
preprocessor.
The modeling system is available at no cost in selected circumstances. Potential users should contact Dr. David Carruthers at "David.Carruthers@cerc.co.uk" for information on acquiring the ADMS-3 modeling system. For additional information on the ADMS-3 Modeling System please link to the Cambridge Environmental Research Consultants Website--EXIT EPA |
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AFTOX
(Air Force Toxics Model) a Gaussian dispersion model that
will handle continuous or instantaneous liquid or gas elevated or
surface releases from point or area sources. Output consists of
concentration contour plots, concentration at a specified location, and
maximum concentration at a given elevation and time.
Executable/Test Case/Readme
-- (173KB,ZIP) |
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ASPEN
(Assessment System for Population Exposure Nationwide)
a Gaussian dispersion model used to estimate toxic air pollutant
concentrations over a large scale domain, such as the entire continental
U. S. Descriptive Statement 
ASPEN User's Guide
ASPEN Modeling System (ftp download)
EMS-HAP
(Version 3.0)
(Emissions Modeling System for Hazardous Pollutants) an
emissions processor that performs the steps needed to process an
emission inventory for input into the ASPEN model or the ISCST3 model.
Descriptive Statement
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| AVACTA II a Gaussian model in which atmospheric dispersion phenomena are described by the evolution of plume elements, either segments or puffs. It can be applied for short (1 day) simulations in both transport and calm conditions. Available from Dr. Paolo Zannetti, QEP-Principal Exponett, Inc., 149 Commonwealth Dr., P.O. Box 3015, Minlo Park, CA 94025; PH 650 688-6962. |
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CAMx
(Comprehensive Air Quality Model with Extensions)
Infrormation related to this model can be found on the 7th Modeling Conference web page under Notice of Proposed Rule Making. |
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CDM2
(Climatological Dispersion Model) a
climatological steady-state Gaussian plume model for determining
long-term (seasonal or annual) arithemetic average pollutant
concentrations at any ground-level receptor in an urban area.
Code/Executable/Test Case
-- (76KB,ZIP) |
| CMAQ (Community Modeling Air Quality) a multiscale, one atmosphere model which is designed to assist the environmental management community's ability to evaluate the impact of air quality management practices for multiple pollutants at multiple scales and equip the scientist's ability to better understand, and simulate chemical and physical interactions in the atmosphere; available from the Models-3 website. |
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DEGADIS
(Dense Gas Dispersion Model) simulates the
atmospheric dispersion at ground-level, area source dense gas (or
aerosol) clouds released with zero momentum into the atmospheric
boundary layer over flat, level terrain. The model describes the
dispersion processes which accompany the ensuing gravity-driven flow and
entrainment of the gas into the boundary layer.
Code/Executable --
(933KB,ZIP) |
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EKMA
an empirical, city-specific model which is used to fill
the gap between more sophisticated photochemical dispersion models and
proportional (rollback) modeling techniques.
Code/Executable/Test
Case,Input Generator & |
| ERT (Visibility Model) a Gaussian dispersion model designed to estimate visibility impairment for arbitrary lines of sight due to isolated point source emissions by simulating gas-to-particle conversion, dry deposition, NO to NO2 conversion and linear radiative transfer. Available from NTIS, Order Number PB96-501978, doc. PB96-171855.. |
| HGSYSTEM a collection of computer programs designed to predict the source-term and subsequent dispersion of accidental chemical releases with an emphasis on denser-than-air (dense gas) behavior. Available from NTIS, Order Number PB96-501960. |
| HOTMAC/RAPTAD HOTMAC is a 3-dimensional Eulerian model for weather forecasting; RAPTAD is a 3-dimensional Lagrangian random puff model for pollutant transport and diffusion. These models are used for prediction of transport and diffusion processes for complex terrain, coastal regions, urban areas, and around buildings where conventional models fail. Available from YSA Corporation, (505) 989-7351. See www.ysasoft.com. |
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HYROAD
HYROAD (HYbrid ROADway Model) integrates three historically
individual modules that simulate the effects of traffic, emissions and
dispersion. The traffic module is a microscale transportation
model which simulates individual vehicle movement. The emission
module uses speed distributions from the traffic module to determine
composite emission factors; spatial and temporal distribution of
emissions is based on the vehicle operation simulations. The model
tracks vehicle speed and acceleration distributions by signal phase per
10-meter roadway segment for use in both emissions distribution and for
induced flows and turbulence. The dispersion module uses a Lagrangian puff formulation, along with a gridded non-uniform wind and
stability field derived from traffic module outputs, to describe
near-roadway dispersion characteristics. HYROAD is designed to
determine hourly concentrations of carbon monoxide (CO) or other
gas-phase pollutants, particulate matter (PM) and air toxics - in
consultation with appropriate Reviewing Authority - from vehicle emissions at receptor locations that
occur within 500 meters of the roadway intersections. Executable, Test Case, README (13.5 MB, ZIP) Model Formulation -- (1.8KB, ZIP) User's Guide -- (1KB, ZIP) |
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LONGZ Information on this model can be found on the Dispersion Models web page under Screening Tools. |
| MTDDIS (Mesoscale Transport Diffusion and Deposition Model for Industrial Sources) a variable-trajectory Gaussian puff model applicable to long-range transport at point source emissions over level or rolling terrain. It can be used to determine 3-hour maximum and 24-hour average concentrations of relatively nonreactive pollutants from up to 10 separate stacks. Available from Dr. I.T. Wang, Combustion Engineering, Environmental Monitoring and Services , Inc. 2421 West Hillcrest Drive, Newburn Park, CA 19320. |
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OBODM
(Open Burn/Open Detonation Model) intended
for use in evaluating the potential air quality impacts of the open
burning and detonation (OB/OD) of obsolete munitions and solid
propellants. OBODM uses cloud/plume rise dispersion, and
deposition algorithms taken from existing models for instantaneous and
quasi-continuous sources to predict the downwind transport and
dispersion of pollutants released by OB/OD operations.
Executable/Test Case
-- (7/31/03)(380KB,ZIP) |
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OZIPR
(A one-dimensional photochemical box model) an
alternative version of the OZIP model (see EKMA)
that deals with air toxic pollutants. Code/Executable/Test Inputs -- (907KB,ZIP) README(first) User's Guide Addendum
to the User's Guide
Supporting Report also
available from NTIS;
Appendices :
A,
B,
C,
D,
E,
F(A Simplified Approach for Estimating Secondary Production of Hazardous Air Pollutants (HAPS) Using the OZIPR Model, EPA-454/R-99-054.) |
| PAL-DS(Point, Area, Line Source Algorithm with Deposition and Sedimentation) a method of estimating short-term dispersion using Gaussian-plume steady-state assumptions. The model can treat deposition of both gaseous and suspended particulate pollutants in the plume since gravitational settling and dry deposition of the particles are explicitly accounted for. Available from NTIS, Order Number PB90-500802. |
| Panache an Eulerian (and Lagrangian for particulate matter), 3-dimensionl finite volume fluid mechanics code designed to simulate continuous and short-term pollutant dispersion in the atmosphere, in simple or complex terrain. Available from Transoft US. Inc., 818 Reedy Creek Rd., Cary, NC 27513-3307. Phone 919 380-7500. |
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PLUVUEII
a model used for estimating visual range reduction and
atmospheric discoloration caused by plumes resulting from the emissions
of particles, nitrogen oxides, and sulfur oxides from a single source.
The model predicts the transport, dispersion, chemical reactions,
optical effects and surface deposition of point or area source
emissions.
Code/Executable/Test Case
-- (782KB,ZIP) |
| PPSP (Maryland Power Plant Siting Model) a Gaussian dispersion model applicable to tall stacks in either rural or urban areas, but in terrain that is essentially flat (on a scale large compared to the ground roughness elements). Available from Power Plant Siting Program, Department of Natural Resources, Tawes State Office Building, Annapolis, MD 21401, Attn: Dr. Michael Hirschfield. |
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RAM
(Gaussian-Plume Multiple Source Air Quality Algorithm)
a steady-state Gaussian plume model for estimating concentrations of
relatively stable pollutants, for averaging times from an hour to a day,
from point and area sources in a rural or urban setting. Level
terrain is assumed.
Code/Executable/Test Case
-- (144KB,ZIP) |
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REMSAD
(Regulatory Modeling System for Aerosols and
Deposition) a three dimensional grid-based Eulerian air
quality model. REMSAD simulates concentrations and deposition of
atmospheric pollutants over large spatial scales (i.e. contiguous US).
Air pollution issues meant to be addressed by REMSAD include PM2.5,
Regional Haze, and toxic, nitrogen, and acid deposition. REMSAD
provides spatially and temporally resolved air concentration, visibility
and deposition values. Recent improvements to the modeling sysytem
include expanded treatment of mercury chemistry.
For information on how to acquire the latest available version, 7.03, of REMSAD please link to the ICF Consulting/Systems Applications International's REMSAD website. -- EXIT EPA |
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RPM-IV
(Reactive Plume Model) a model used for
estimating short-term concentrations of primary and secondary pollutants
resulting from point or area source emissions. The model is
capable of simulating the complex interaction of plume dispersion and
non-linear photochemistry. Two main features of the model are: (1)
the horizontal resolution within the plume, which offers a more
realistic treatment of the entrainment process and (2) its flexibility
with regard to choices of chemical kinetic mechanisms.
Code/Executable/Test Case
-- (76KB,ZIP) |
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SCIPUFF
Second-order Closure Integrated PUFF Model Information related to this model can be found on the 7th Modeling conference web page under Notice of Proposed rule Making. |
| SCSTER (Multisource Model) a modified version of the CRSTER model. The primary distinctions of SCSTER are its capability to consider multiple sources that are not necessarily collocated, its enhanced receptor specifications, it variable plume height terrain adjustment procedures and plume distortion from directional wind shear. Available from Bryan Baldwin, Research Program Supervisor, Air Quality Program, Southern Company Services, Post Office Box 2625, Birmingham, AL 35202. |
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SDM
(Shoreline Dispersion Model) a
multiple-point Gaussian dispersion model that can be used to determine
ground level concentrations from tall stationary point source emissions
near a shoreline.
Code/Executable/Test Case
-- (328KB,ZIP) |
| SHORTZ Information related to this model can be found on the Dispersion Models web page under Screening Models. |
| Simple Line Source Model A simple steady- state Gaussian plume model which can be used to determine hourly (or half-hourly) averages of exhaust concentrations within 100m from a roadway on a relatively flat terrain. Available from Dr. D.P. Chock, Environmental Science Department, General Motors Research Laboratories, General Motors Technical Center, Warren, MI 48090. |
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SLAB
The SLAB model treats denser-than-air releases by
solving the one-dimensional equations of momentum, conservation of mass,
species, and energy , and the equation of state. SLAB handles
release scenarios including ground level and elevated jets, liquid pool
evaporation, and instantaneous volume sources.
Code/Executable/Test Case -- (111KB,ZIP) |
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UAM-V(
The UAM-V Photochemical Modeling System ) The Urban
Airshed Model (UAM-V) is a three dimensional photochemical grid model
that calculates concentrations of pollutants by simulating the physical
and chemical processes in the atmosphere. The updated
version of the UAM-V modeling system (version 1.3) includes
process-analysis capabilities, an enhanced chemical mechanism (enhanced
treatment of hydrocarbon and toxic species), updated deposition and
nested-grid algorithms, a flexible coordinate system (including Lambert
conformal), and user-selection of a "standard" or "fast" solver.
The updated version 1.30 and the earlier version 1.24 (OTAG version) are available from the developer Systems Applications International (SAI) for general use and at no cost to interested users. To obtain a copy of the UAM-V modeling system, potential users should contact Sharon Douglas (SDouglas@icfconsulting.com) for information concerning registration and acquisition of the system. Potential users are encouraged to register with SAI to receive information on updates to the code, training workshops, and available databases. For additional information on the UAM-V modeling system please link to the SAI UAM-V website -- EXIT EPA. |
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UAM-IV
(Urban Airshed Model IV) an urban scale,
three dimensional, grid type numerical simulation model. The model
incorporates a condensed photochemical kinetics mechanism for urban
atmospheres. UAM-IV is designed for computing ozone
(O3) concentrations under short-term, episodic conditions lasting one or
two days resulting from emissions of oxides of nitrogen (NOx), volatile
organic compounds (VOC), and carbon monoxide (CO). The model
treats VOC emissions as their carbon-bond surrogates.
README --
Please read before downloading the UAM-IV system. |
This area
provides a list of programs and utilities that are used in support of some
of our dispersion models, especially those listed under
preferred/recommended. Note that utilities that are designed for use
with particular models will be found with those models. The programs
listed in this section are:
BPIP,
CALMPRO, CHAVG and CONCOR.
Note: To access and view all
available Model Change Bulletins, click here.
Note: Selected User's Guides
are available from NTIS.
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BPIP
(Building Profile Input Program) - a PC-based program
designed to incorporate the concepts and procedures expressed in the
Good Engineering Practice (GEP) technical support document, building
downwash guidance, and other related references that correctly calculate
building heights (bh) and projected building widths (pbw) for simple,
multi-tiered, and groups of structures.
This most recent version of BPIP, 4/21/04, has been upgraded with
allocatable arrays while maintaining the basic functionality of the
program.
Code/Executable/Test Case--
(276KB,ZIP) |
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CALMPRO
(Calms Processor) a meteorological processor which
provides consistent application of handling calms by setting the wind
direction of the calm hour to the last reported wind direction and the
wind speed to 1 m/s.
Code/Test Case/Readme
-- (12KB,ZIP) |
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CHAVG
a post-processor program for computing running averages (averages that
begin each hour and overlap) and end-to-end averages (averages that do
not overlap) from hourly concentrations files.
Code/Test Case/Readme
-- (32KB,ZIP) |
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CONCOR
a program for converting latitude/longitude coordinates
to UTM or UTM coordinates to latitude/longitude.
Code/Executable/Test Case/Readme
-- (31KB,ZIP) |
This area
provides the following model tutorials::
CTSCREEN,
ISC2, SCREEN,
TSCREEN, and
VISCREEN.
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Office of Air and Radiation | Office of Air Quality Planning and Standards |
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