Computer simulations are increasingly used in various industries. This paper describes the airflow in the atmospheric boundary layer above the city district. It is known that the planned positioning of individual buildings can achieve better street ventilation, which allows the removal of harmful particles that accumulate in the zones of human habitation. Previous research has shown that a single tall building in an otherwise uniform block of buildings can have a significant impact on the airflow field. In this paper, using the computer package OpenFOAM, computer simulations of airflow in the atmospheric boundary layer above such a uniform block with one tall building were made. The flow of a stationary turbulent homogeneous atmospheric boundary layer is modeled. The obtained results for one height of a tall building were confirmed by comparison with the existing results, and then the influence of the change in the height of the tall building on the change of the airflow image in the city district was studied. It has been shown that increasing the height of a tall building results in more favorable phenomena in the field of flow, such as rising currents on the leeward side of the tallest building, the formation of vortices and lateral flow in avenues. These phenomena potentially lead to the rise of harmful particles above the roofs of buildings and their removal from the zone of human habitation.