Mesoscale simulations at Mt. Etna volcano (Sicily, Italy), validated by measurements, highlight the fundamental role played by the local wind field in the dispersion of a gaseous volcanic plume. During the night, downslope surface winds (over-hill flow and katabatic breezes) force the plume to follow the steep morphology, whereas during the day very frequent NNW synoptic winds crash into the cone and are contrasted by SE strong sea breezes and anabatic winds, with the consequent formation of convective ascendant currents. The local mesoscale wind reconstruction can provide useful improvements in gaseous flux estimation. Far away synoptic wind velocities, often used in these flux evaluations, might be inadequate. We propose a 3D numerical mesoscale wind reconstruction to evaluate plume dynamics (and from it plume flux and potential hazard) throughout all the hours of the day.