Effect of Wind Direction on Airflow and Pollutant Dispersion Inside a Street Intersection

The airflow and pollutant dispersion inside a street intersection under six different wind directions (θ=0°, ±10°, ±30° and 45°) were evaluated using the computational fluid dynamics (CFD) approach. The numerical results reveal that the flow and pollutant dispersion inside a street intersection are greatly influenced by the incoming wind direction: (1) The air exchange between the outer flow and the intersection interior is the strongest under the wind direction angles of ±10°, while it is the weakest for the wind direction angle of 45°; (2) the pollutants from the intersection centre at the ground level are transported into the different streets depending on the various wind directions.