Human beings generate airflows by several mechanisms, such as the motion of their body parts which are truly unsteady and turbulent. These airflows participate to pollutant transport and may disturb the efficiency of ventilation-based mitigation devices (safety cabinets, fume cupboards and hoods, air curtains, etc.), which can have serious consequences on health and safety of the users. Even if these phenomena are well known, there is so far no mean of characterizing or quantifying their effects precisely. A first step is to simulate the pollutant transport within a turbulent flow in a confined area with high Péclet turbulent number. Two CFD tools are used (ANSYS Fluent and homemade code FUGU) and the pollutant transport equation is solved thanks to standard (Upwind, Central Differencing), hyperbolic (Weno) and semi-Lagrangian (VOF-SM [1]) schemes. The turbulence modelling is based on various LES formulations (Smagorinsky, Wale, TKE, Mixed [2]). The simulations are validated and compared to devoted experiments driven by INRS.