Dispersion modelling of atmospheric contaminants resulting from terrorist attacks and accidental releases in urban areas

After the September 11th, 2001, it has become clear that a new type of event can also trigger the need for rapid response and exposure, environmental and human health impact analysis. The use of specific numerical tools, such as computational fluid dynamic (CFD) models, combined with exposure studies can contribute to the simulation of the effect of a terrorist attack on local air quality and on human health, in an urban area. The main objective of this study is the development of an exposure module to chemical agents and its integration in the CFD model VADIS, in order to estimate the cumulative exposure and the number of persons exposed above specific limit values of Sulphur Mustard HD agent. The improved numerical model was applied to a selected case study in the Lisbon urban area, in order to determine the effects on the population, as a result of a terrorist attack scenario with chemical agent Sulphur Mustard HD. The number of inhabitants exposed to HD agent concentrations above 100 mg.min.m^-3, capable of causing the first noticeable effects, above the medium incapacitating dosage (ICt50) of.