Numerous versions of the AERMOD model have been released over the years. These updates include new algorithms, enhancements to existing features, bug fixes, and more. New model versions are published by the US EPA to the Support Center for Regulatory Atmospheric Modeling (SCRAM) website. In the United States, the newly published model officially becomes the preferred version of the model.
There are many situations where a modeler may wish to use an older version of the AERMOD executable. For example:
- Regulators in some countries may still mandate the use of an earlier version of AERMOD.
- A specific version of AERMOD may be stipulated in the modeling plan and permit application, even though a newer version of the model may have become available since the project started.
- There are certain situations where a custom recompiled version may be required to support specific non-regulatory options or to implement advanced modeling configurations such as the ability to run in a parallel processing environment.
The newly released AERMOD View Version 10.0 supports the latest U.S. EPA AERMOD model update (version 21112). It also supports backwards compatibility for AERMOD versions dating back to 2012 (version 12345). To change the version of AERMOD used by the interface, complete the following steps.
Step 1: Open the File menu and select Preferences.
Step 2: The various models available in AERMOD View are listed under the EPA Models/Limits section. Select AERMOD.
Step 3: The default executable is AERMOD.EXE which represents the 32-bit version of the most recent US EPA executable (currently 21112). Since the version 18081 release, the EPA has included both 32-bit and 64-bit compilations of the model. If your computer runs a 64-bit operating system, you can choose the X64 model.
Select the drop-down list to see all available model executables.
EPA Figure Describing Potential Process for Model Option Progression
Step 4: Select the version of the model you want to use. Executables named AERMOD_MPI_LAKES_xxxxx.EXE represent the parallelized version of the listed model number. This version is developed by Lakes Software and is included free of charge for AERMOD View users who have a computer with multiple processors (see installation instructions for further information).
Note that the selected version is ‘sticky’. You will continue to run with the selected executable until the next time a change is made.
Step 5: Users can also select their very own recompiled version of AERMOD by selecting the User-Specified radio button. Use the Browse button to search your computer for the desired executable. When modeling with a User-Specified executable, it is the user’s responsibility to verify all the proper model options are selected.