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 December 20, 2016, the Environmental Protection Agency (EPA) finalized several additions and changes to its Guideline on Air Quality Models (Guideline) now in the 2016 Appendix W Final Rule.

These include the update of AERMOD from version 15181 to version 16216r.

AERMOD 16216r includes various bug fixes and some enhacements:

  • the previous PVMRM option has been replaced with the PVMRM2 option introduced in 15181. The PVMRM name was retained;
  • replacement of the Ambient Ratio Method (ARM) Tier 2 option with a revised ARM2 option;
  • incorporation of a buoyant line source option, based on the BLP model;
  • removed the requirement for specifying the BETA option for application of the PVMRM, OLM, and ARM2 options for NO2;
  • removed the BETA/Non default status of POINTCAP and/or POINTHOR sources for horizontal and capped stacks;
  • removed the BETA/Non-default status of MMIF meteorological data;

AERSCREEN, the recommended screening model for simple and complex terrain for single sources and options for multi-source screening based on AERMOD has been updated accordingly, to version 16216r.

Along with the update to AERMOD, the 2016 Appendix W Final Rule reports that US-EPA is finalizing replacement of CALINE3 with AERMOD as the preferred appendix A model for refined mobile source applications including fine particle pollution (PM2.5, PM10), and carbon monoxide (CO) hot-spot analyses. The use of CAL3QHC for CO screening analyses was retained.

Also, the EPA is taking final action to codify the screening approach to address long-range transport for purposes of assessing NAAQS and/or PSD increments and removing CALPUFF as a preferred model in appendix A for such long-range transport assessments.

The US-EPA has also released an updated version of the Mesoscale Model Interface Program (MMIF) program. This program is used to convert the prognostic meteorological data into a format suitable for dispersion modeling applications. This update simplifies the use meteorological models for near-field applications where there are no representative stations, and it is prohibitive or not feasible to collect adequately representative site-specific data.

According to 2016 Appendix W Final Rule, US-EPA recommends to use CALPUFF as a screening technique along with other Lagrangian models that may be used as part of the long-range screening approach without alternative model approval.

One of such Lagrangian particle models is LAPMOD.