Three regulatory air dispersion models used most popularly are reviewed here: AUSPLUME (Australia), CALPUFF and ISC3 (USA). These air dispersion models can be also used for odour dispersion modelling.

AUSPLUME Model

Ausplume, developed in 1986, is now a regulatory plume dispersion model in Australia. Using Ausplume dispersion model, the ground level concentration of any pollutions or odours emitted from different sources: point sources (like stacks), area sources and volume sources, can be predicted. To predict the impact of a source, the information about the sources, meteorological data, receptor information and topographic data are the major requirements for modeling. The latest version of Ausplume Version 6.0 (April 2004, replacing Ausplume Version 5.4) is the EPA approved regulatory model. Ausplume Model and the user's guide "Ausplume Gaussian Plume Dispersion Model Technical User Manual" can be obtained from EPA VIC by calling 03-8458 2364 in Australia or 61-3-9695 2722 internationally.

CALPUFF Model

The CALPUFF model is a multi-layer, multi-species non-steady-state puff dispersion model that simulates the effects of time- and space-varying meteorological conditions on pollution transport, transformation and removal. It is developed and distributed by Earth Tech. Inc. The CALPUFF model has been approved by US EPA as the preferred model for assessing long range transport of pollutants and their impacts on Federal Class I areas and on a case-by-case basis for certain near-field applications involving complex meteorological conditions. The CALPUFF modeling system includes a diagnostic 3-D meteorological model (CALMET), a puff-based dispersion model (CALPUFF), and a post-processing package (CALPOST). The CALPUFF modeling system is available free from Earth Tech. Go to download: CALPUFF GUI Installation (CALGUI.ZIP 10.2 Mb, 23.2 Mb installed)

ISC3 Model

Industrial Source Complex Model (ISC3) is a steady-state Gaussian plume model which can be used to assess pollutant concentrations from wide variety of sources associated with an industrial complex. ISC3 models are especially designed to support the US EPA's regulatory modeling programs. ISC3 operates in both short term (ISCST3) and long-term (ISCLT3) modes. ISCST3 - Industrial Source Complex - Short Term The latest version of the regulatory model ISCST3 was released by US EPA on 27 February 2002. It can be downloaded free at: ISCST.ZIP - 1.65 MB 02/27/02 (Executable, Source, Test Cases) ISCLT3 - Industrial Source Complex - Long Term ISC3 Long Term dispersion model is used to model emissions with long-term averaging periods. It can be download free at: ISCLT3-L.ZIP - 220,542 bytes ISC3 User's Guide (ISCST3 & ISCLT3) Can be downloaded at:ISC3UG.ZIP - 552 Kb 04/27/00 (User's Guides - All Volumes - WP format)

Comparison study of air dispersion models

Some comparison studies of air dispersion models have been carried out by The Environment Agency. The Archive of Protocol for Comparing Air Dispersion Models including the following three reports on CD is available Here.

• A Review of Dispersion Model Inter-comparison Studies Using ISC, R91, AERMOD and ADMS (P353.pdf)
• An Inter-comparison of the AERMOD, ADMS and ISC Dispersion Models for Regulatory Applications (P362.pdf)
• Evaluation of Atmospheric Dispersion Models: AERMOD (PS336.pdf)