State-of-the-art models of dispersion of contamination in the urban environment and industrial areas employ a CFD approach in order to calculate turbulent characteristics of flow around buildings with complex geometry. The main area of application of these models is to facilitate licensing of potentially hazardous facilities and assessment of meteorological conditions in the urban environment. The usage of the most popular commercial CFD software with regard to modelling flows in the urban environment is significantly limited by the requirement for computational mesh refinement near the surface of the building in order to adequately resolve the characteristic scales in the viscous and buffer sublayers. On the other hand, models based on the traditional gaussian approach cannot take into account the complex aerodynamic effects in order to calculate turbulent characteristics of flow around buildings with complex geometry, including the subtleties concerning atmospheric emissions of gas-aerosol substances. Therefore, the authors developed a robust, highly specialized CFD-RANS model and a calculation code for modelling the atmospheric dispersion of contamination under conditions of a complex three-dimensional geometry that do not require mesh refinement. The authors verified this model using extensive database obtained both in the course of field experiments as well as of wind tunnel experiments. The verification results showed that the developed model satisfies the acceptance criteria for the quality of modelling along with foreign general-purpose codes and highly specialized codes.