AERMOD is the preferred air quality dispersion model of US-EPA and it is used all over the world as reference model for regulatory purposes.

On April 24, 2018, the U.S. EPA announced revisions to the AERMOD air dispersion model and its components AERMET, the meteorological data preprocessor, and AERMAP, the terrain data preprocessor.

These revisions include the update of AERMOD from version 16216r to version 18081.

AERMOD 18081 includes various bug fixes and some enhacements:

  • Fixed a bug in the PRIME downwash algorithm.
  • Urban SO2 Half-life for Non-Default Applications.
  • For multi-year runs POSTFILE will ouptut individual years, not the multi-year average.
  • Added a summary table in aermod.out for the Buoyant Line Source Parameters.
  • Fixed bug in AERMOD Seasonal Assignment for calculation of cuticle resistance for ozone.
  • Updated ARM2 Error/Warning Messages for Range Checks.
  • Fixed bug in Background Sectors Output.
  • Apply minimum wind speed.
  • Fixed bug to avoid infinite loops when the Meteorological Surface File is empty.
  • ARM2 was extended for application to buoyant line sources.
  • Added capability to specify control filename (.inp) and standard output filename (.out) on the command-line.
  • Removed the individual BETA options LOWWIND1, LOWWIND2, LOWWIND3 and replaced with LOW_WIND ALPHA option.
  • Ambient Ratio Method (ARM) replaced with ARM2.

AERSCREEN, the recommended screening model for simple and complex terrain for single sources and options for multi-source screening based on AERMOD at the moment is still based on version 16216r.