The influence of street architecture on flow and dispersion in street canyons

The paper presents an overview of the influence of street architecture on the wind and turbulence patterns in street canyons and discusses the effects on local air quality. The findings of recent experimental and numerical studies are summarized and wind-tunnel data sets are presented that illustrate the flow-field variability. It is shown that small-scale features of the street architecture play an important role. The formation of a vortex inside the street canyon is affected by the roof configuration. In shorter street canyons, the flow component along the street becomes important for pollutant transport. These results are of importance for urban air quality modeling in particular when dealing with pollution problems caused by road traffic. Furthermore, the findings should be taken into account in fast response models that are used to assess critical areas in the case of accidental or non-accidental releases of hazardous material in urban areas.