The impact of traffic-related pollutant on indoor air quality in buildings near main roads

Traffic-related pollutant has been recognized as an air pollution hot spot due to its large emission rate and great health impacts for the exposed population. In the present investigation, a computational fluid dynamics technique is used to evaluate the effect of traffic pollutions on indoor air quality of a naturally ventilated building. The transport of street-level nonreactive pollutants emitted from motor vehicles into the indoor environment is simulated using the RNG k-ε model of the turbulent flows and the pollutant transport equations. Three typical configurations of street canyons and six ventilation scenarios are considered. It is found that the layout of street canyon affects not only the airflow pattern but also the ventilation rates, paths and indoor air quality for that building. When the studied building is located in the street canyon with aspect rate 0.2, using the leeward cross-flow ventilation with windward upper vent can effectively lower incoming vehicle pollutants and maintain a desirable air change rate during traffic rush hours. But when the street canyon aspect rate is equal to 0.5, this ventilation mode has no significant advantage compared with other cross ventilation modes. Moreover, the leeward side vents may become a significant factor contributing to indoor concentration of traffic pollutants when the studied buildings are located in a narrow street such as aspect rate equal to 1.