SPRAY is a three dimensional model designed to simulate the airborne pollutant dispersion, able to take into account the spatial and temporal inhomogeneities of both the mean flow and turbulence. Concentration fields generated by point, areal or volume sources can be simulated by the model. The trajectory of the airborne pollutant is simulated through virtual particles: the mean motion is defined by the local wind and the dispersion is determined solving the Langevin stochastic differential equations for the velocity fluctuations, reproducing the statistical characteristics of the turbulent flow. Different portions of the emitted plumes can therefore experience different atmospheric conditions, allowing realistic reproductions of complex phenomena, such as low wind-speed conditions, strong temperature inversions, flow over topography, landuse and terrain variability. ISAC-Torino has a long-term collaboration with Arianet srl in Spray development: Spray is now a commercial model licensed by Arianet. Spray can be driven by a diagnostic mass-consistent model (SWIFT, developed at Aria Technologies, Paris) and by the atmospheric model RAMS (in the modelling suite RMS developed at ISAC-Torino).