software ESTET, developed by EDF's Laboratoire National d'Hydraulique. MODIM (Slovak Republic) – A model for calculating the dispersion of continuous, neutral or buoyant plumes on a local to regional scale. It integrates a Gaussian plume model for single or multiple point and area sources with a numerical model for line sources, street networks and street canyons. It is intended for regulatory and planning purposes. MSS (France) – Micro-swift-spray is a Lagrangian particle model used to predict the transport and dispersion of contaminants in urban environments. The SWIFT portion of this model predicts a mass-consistent wind field that considers terrain; no-penetration conditions for building boundaries; Rockle zones for recirculation, edge, and rooftop separation; and background and locally generated turbulence. The spray portion of the tool handles the dispersion of passive gases, dense gases, and particulates. Spray also accounts for plume buoyancy effects, wet and dry depositions, and calculates microscale pressure fields for integration with building models. The MSS development team is found at ARIA Technologies (France) and U.S. integration activities are led by Leidos. Validation testing of MSS has been done in conjunction with JEM and HPAC tool releases and the model is coupled with SCIPUFF/UDM to create a nested dispersion capability inside HPAC. For more information on MSS see http://www.aria.fr. MUSE (Greece) – A photochemical atmospheric dispersion model developed by Professor Nicolas Moussiopoulos at the Aristotle University of Thessaloniki in Greece. It is intended for the study of photochemical smog formation in urban areas and assessment of control strategies on a local to regional scale. It can simulate dry deposition and transformation of pollutants can be treated using any suitable chemical reaction mechanism. OML (Denmark) – A model for dispersion calculations of continuous neutral or buoyant plumes from single or multiple, stationary point and area sources. It has some simple methods for handling photochemistry (primarily for NO2) and for handling complex terrain. The model was developed by the National Environmental Research Institute of Denmark. It is now maintained by the Department of Environmental Science, Aarhus University. For further reference see as well: OML home page ONM9440 (Austria) – A Gaussian dispersion model for continuous, buoyant plumes from stationary sources for use in flat terrain areas. It includes plume depletion by dry deposition of solid particulates. OSPM (Denmark) – The operational street pollution model (OSPM) is a practical street pollution model, developed by the National Environmental Research Institute of Denmark. It