Motor vehicle traffic is one of the aspects of urban life in contemporary cities. At the same time, particles resulting from the combustion of fuel in the engines of these vehicles are considered one of the most important factors of air pollution in metropolitan areas. These particles are transported to the surrounding spaces by the wind, which reduces the air quality in the spaces built in the vicinity of high-traffic urban arteries. At the same time, it seems that by choosing the appropriate form for buildings built in these areas, it is possible to provide proper ventilation and prevent pollutants from entering the open spaces of these complexes to some extent. Accordingly, the present study raises the question of the extent to which the layout form and elongation pattern of buildings in building complexes located in the vicinity of high-traffic urban highways affect the air quality in the open spaces between them, and numerically investigates this issue using the CFD simulation method. In this study, three parameters of air velocity, air age, and the concentration of pollutants accumulated in the central open space between buildings are used to measure air quality. In order to extract the case studies of the research, initially three building elongation patterns were considered, including a square pattern, a rectangular pattern with elongation perpendicular to the prevailing wind, and a rectangular pattern with elongation in the direction of the prevailing wind. Then, each of the forms was placed in 6 layout patterns. Finally, 18 case studies were extracted, and in each, a fixed central open space with an area of 225 was considered as the study area. All case studies were considered at a distance of 35 meters from an urban highway as a source of pollutant production. The results of the research showed that increasing spatial confinement due to the centripetal arrangement in building complexes, despite reducing the concentration of pollutants in their central open spaces, severely reduces the quality of ventilation in these spaces. Also, increasing the permeability of walls leading to pollutant production sources can be a factor in transferring pollutant particles to open spaces between complexes. Therefore, the elongation of building blocks in the direction perpendicular to the prevailing wind direction is one of the factors that can prevent pollutants from entering the leeward space in them.