This paper describes the computer code LOCADIS which we developed to model local aerosol dispersion in the atmosphere. The code can simulate (1) the release of contaminants in aerosol form, (2) the interaction of aerosols with other particles in the atmosphere, (3) the atmospheric dispersion of released aerosols, and (4) the deposition of contaminants on the ground and surrounding infrastructure. The code is also linked with the RIVMORPH model, which describes transport in surface water and sedimentation. LOCADIS is based on an integrated model of transport processes in non-homogeneous systems. It includes unsteady-state conservation equations for separate phases in a two-dimensional space, equations of transport processes at interface boundaries, descriptions of geometrical characteristics of a source, and heat- and mass-exchange of the source with the surroundings. LOCADIS can be used as a stand-alone code model, or as part of an expert system supporting decision-making after an industrial accident. A case study involving atmospheric dispersion and deposition around a release source is also presented.