Introduction. To study the urbanized territory as a system, an approach was used that allows assessing gaseous and dispersed atmospheric pollution using a unified scale of environmental hazard. The features of air pollution in urban areas were considered, where a significant number of stationary and mobile sources of negative environmental impact are concentrated in limited overpopulated areas.The purpose of the study. the use of theoretical foundations for a systematic assessment of the level of environmental hazard of an urbanized area under the influence of the road network due to a combination of gaseous and dispersed atmospheric pollution.Methods and materials. Based on the improved model of the Urbanized Territory system, the following hypothesis is proposed: 1) motor traffic flows are both independent sources of formation of dispersed particles and sources of uplifting and spreading of particles, which in the presence of gaseous pollutants increases the level of environmental hazard of atmospheric pollution in an urbanized area; 2) atmospheric pollution of an urbanized area is formed when gaseous pollutants and dispersed particles from the street and road network are superimposed on the polluting background of other elements of the Urbanized territory system.Results. The distribution maps of the calculated complex index of atmospheric pollution were obtained for the most problematic areas of the urbanized territory of Naberezhnye Chelny - Prospekt Mira and Kazansky Prospekt. The obtained results characterize the change in the level of environmental hazard of urbanized areas when gaseous pollutants and dispersed particles from the street and road network are superimposed on the polluting background of other elements of the Urbanized territory system.Discussion and conclusion. Based on the generalization and comparison of the results of previous and current studies of the authors, comparing them with the results of other researchers, the hypothesis was fully confirmed. Conclusion. With the confirmation of the hypothesis, the goal of the study was achieved, which has scientific novelty and practical significance for the arrangement of a favorable and comfortable urban environment.