Horizontal and vertical airflow characteristics and pollutant transport & diffusion in a residential area in Haizhu district

Guangzhou

during summer and winter

were simulated by using three-dimensional micro-scale meteorological model ENVI-met based on the distinct meteorological conditions

and then validated with the field observation of CO concentration. The results showed that there existed wind corner flow

climbing airflow and landslide

and backflow in the area

which lead to abnormal concentrations of pollutants at different locations and heights. While incoming flow was parallel to street canyon

a high pollutant area can be observed in the convergence zone of airflows. While incoming flow is perpendicular to street canyon

there exist two situations: airflows in opposite direction of incoming flow were observed in the regions behind independent building or between the lower upwind building and higher downwind building

resulting in highly polluted regions on the leeward side of the street; airflows in the same direction of incoming flow were observed

causing more cumulative pollutants in the mid-east of the street in the regions between the higher upwind building and lower downwind building. The efficiency of vertical diffusion in the street valley was the highest in regions between the lower upwind building and higher downwind building

the second in regions between the higher upwind building and lower downwind building

and the lowest over independent building. The results also showed that ENVI-met model can be used to simulate pollutant dispersion at street scales.