Problem statement. The task of assessing the level of atmospheric air chemical pollution in the case of an extreme situation resulting in a heptyl spill on the territory of industrial facility is considered. An analysis of the pollution zones formation both at industrial sites and in the residential area located near the industrial facility is conducted. To solve such a problem, it is necessary to develop multifactor mathematical models that allow for the rapid determination of the pollution areas formed in an extreme situation. The purpose of the article. To develop a computer model for operational analysis of pollution areas formed during the emergency emission of chemically hazardous substances into the atmosphere. Methodology. The computer model was developed on the basis of a numerical model, which is a differential analogue of the multifactor kinematic equation for impurities mass transfer in atmospheric air. The mass transfer equation takes into account the three-dimensional field of wind speed, atmospheric diffusion, and the intensity of the chemically dangerous substance release into the air. A four-step finite-difference splitting scheme is used for numerical integration of the three-dimensional mass transfer equation. Determination of the chemically dangerous substance concentration at each cleavage step is implemented according to an explicit formula. An empirical dependence is used to calculate the emission intensity of a chemically hazardous substance from the emergency spill zone. Scientific novelty. A numerical model was developed and its software implementation was conducted for the operational analysis of the formation of accidental pollution areas in the atmosphere. The model takes into account a complex of factors affecting the process of impurity propagation in the atmosphere. Practical value. A program was developed for calculating the dynamics of atmospheric air pollution based on the proposed numerical model. This makes it possible to analyze the consequences of emergency spills on the territory of chemically hazardous objects by the method of a computational experiment. Conclusions. An effective tool for operational analysis of the atmospheric air pollution level due to the emission of chemically hazardous substances is created. The results of the computational experiment are presented.