An experimental investigation of the wind environment and air quality within a densely populated urban street canyon

This paper presents an experimental investigation of wind flow characteristics and air quality along a street canyon located within a dense urban area. Four typical models of a highly populated urban area are studied and wind tunnel experiments are carried out over an extended range of the applied wind directions. The building patterns are represented by 1:100 scale models, where wind velocity and tracer gas concentrations are measured along the two sides of the street. The study results provide evidence that building configurations and wind directions are very important factors in determining both wind flow and pollutant dispersion characteristics within urban domains. Also, the results demonstrate that gaps between buildings are a very important factor to be considered by urban planners and designers, because, for a given building height, larger gaps induce more wind in urban canyons, thus improving the ventilation process.

► We assess wind environment of a pedestrian level domains of highly populated areas.
► Four models of a dense urban area are considered and wind tunnel experiments were carried out in order to examine the effects of the models geometry on wind flow characteristics and hence on the air quality.
► The measured quantities were wind velocity and gas concentration.
► The study results show that the further analysis of the wind environments of the four models is needed to insure a reasonable level of air quality for inhabitants. This can be carried out using the exceedance probability approach, which is introduced in another study by the authors.