Validation of the PMSS modelling system in urban environments and applicability in case of an emergency

Releases of harmful airborne materials may pose a serious threat to the population in case of an accident or a malevolent action. In such a situation, a reliable and rapid assessment of the impacted areas is of highest interest for the security services and their authorities to make decisions and take appropriate protection measures. As these events are more likely to occur in built-up (industrial or urban) places, only 3D flow and dispersion models are adequate to address these complex environments in possibly evolving meteorological conditions. This paper aims to evaluate the PMSS modelling system that comprises a diagnostic and momentum solving flow model and a Lagrangian Particle Dispersion model. PMSS is validated on a panel of experimental test cases from the COST Action ES1006 for both idealized and real urban mock-ups, wind tunnel and in field trials, continuous and puffs releases. The concentrations predicted in various configurations of PMSS are compared to measurements on the basis of statistical metrics. PMSS proves to be compliant with the validation criteria established in literature in the large majority of the test cases and robust enough to be used in the context of emergency response, when fast but still reliable results are needed.