The concentrations fluctuations of a dispersing hazardous gaseous pollutant in the atmospheric boundary layer, and the
hazard associated with short-term concentration levels, demonstrate the necessity of estimating the magnitude of these fluctuations
using predicting models. Moreover the computation of concentration fluctuations and individual exposure in case of dispersion in
realistic situations, such as built-up areas or street canyons, is of special practical interest for hazard assessment purposes. In order to
predict or/and estimate the maximum expected dosage and the exposure time within which the dosage exceeds certain health limits,
the knowledge of the behaviour of concentration fluctuations at the point under consideration is needed. In this study the whole
effort is based on the ‘Mock Urban Setting Test – MUST’, an extensive field test carried out on a test site of the US Army in the
Great Basin Desert in 2001 (Biltoft, 2001; Yee, 2004). The experimental data that was used for the model evaluation concerned the dispersion of a passive gas between street canyons which have been created by 120 standard size shipping containers. The
computational simulations have been performed using the laboratory CFD code ADREA, which has been developed for simulating
the dispersion and exposure of pollutants over complex geometries. The ADREA model is evaluated by comparing the model’s
predictions with the observations utilizing statistical metrics and scatter plots. The present study has been performed in the frame of
the Action COST 732 “Quality Assurance and Improvement of Micro-Scale Meteorological Models”
