MicroSpray is a microscale Lagrangian particle model derived from SPRAY code and able to take into account the presence of obstacles. Microspray is especially oriented to deal with gas dispersion in urban environment and industrial sites. It is a flexible tool including the treatment of several features: plume without initial momentum and with initially arbitrarily oriented momentum, negative or positive buoyancy, elevated and ground level emissions, instantaneous and continuous emissions, time varying sources, cloud spread at the ground due to gravity, bouncing against obstacles and particle reflection at the domain bottom in presence of a dense cloud. Modules treating the phase changes liquid – vapour that may occur at the source, and the latent heat processes in the dispersing cloud, such as aerosol evaporation, have been recently implemented. MicroSPRAY is applied in the frames of MSS (MicroSwift-Spray) and MicroRMS (RAMS-MIRS-SPRAY) modelling systems.