arches, tunnels and walkways can be performed. Dense gas dispersion is simulated using five conservation equations (mass, energy, vertical momentum and two horizontal momenta) based on Glandening et al. (1984) and Hurley and Manins (1995). Plume spread at the ground due to gravity is also simulated by a method (Anfossi et al., 2009), based on Eidsvik (1980). STACKS (The Netherlands) – A Gaussian plume dispersion model for point and area buoyant plumes to be used over flat terrain on a local scale. It includes building effects, NO2 chemistry and plume depletion by deposition. It is used for environmental impact studies and evaluation of emission reduction strategies. STOER.LAG (Germany) – A dispersion model designed to evaluate accidental releases of hazardous and/or flammable materials from point or area sources in industrial plants. It can handle neutral and denser-than-air gases or aerosols from ground-level or elevated sources. The model accommodates building and terrain effects, evaporation of volatile liquid spill pools, and combustion or explosion of flammable gas-air mixtures (including the impact of heat and pressure waves caused by a fire or explosion). SYMOS'97 (Czech Republic) – A model developed by the Czech Hydrometeorological Institute for dispersion calculations of continuous neutral or buoyant plumes from single or multiple point, area or line sources. It can handle complex terrain and it can also be used to simulate the dispersion of cooling tower plumes. TCAM is a multiphase three-dimensional eulerian grid model designed by ESMA group of University of Brescia, for modelling dispersion of pollutants (in particular photochemical and aerosol) at mesoscale. UDM-FMI (Finland) – This model was developed by the Finnish Meteorological Institute (FMI) as an integrated Gaussian urban scale model intended for regulatory pollution control. It handles multiple point, line, area and volume sources and it includes chemical transformation (for NO2), wet and dry deposition (for SO2), and downwash phenomena (but no building effects). VANADIS (Poland) – 3D unsteady state eulerian type model – Demo – 3d dispersion model – please read vanadis_eng.txt. Models developed in Australia AUSPLUME – A dispersion model that has been designated as the primary model accepted by the Environmental Protection Authority (EPA) of the Australian state of Victoria. (update:AUSPLUME V6 will no longer be the air pollution dispersion regulatory model in Victoria from 1 January 2014. From this date the air pollution dispersion regulatory model in Victoria will be AERMOD.) pDsAUSMOD – Australian graphical user interface for AERMOD pDsAUSMET