Keywords: atmospheric dispersion models, gaseous pollutants, isolated building, street canyons, street intersection, wind tunnels, air pollution, environmental pollution, modelling
Gaseous pollutant dispersion around urban-canopy elements: wind tunnel case studies
There is an evident lack of reliable and detailed in situ measurement data for verifying numerical predictions of atmospheric dispersion in the urban environment on sub-meso scales. Wind-tunnel studies of dispersion around typical elements of the urban canopy (isolated buildings, groups of buildings, street canyons) could provide valuable substitutes for field datasets. They can achieve a high resolution of the measured concentration fields, and may be used for evaluation of numerical models and for expert estimates of air quality in the urban environment. This paper presents results of several case studies of gaseous pollutant dispersion in a neutrally stratified wind-tunnel flow. The following cases have been investigated: (1) Point source: (a) isolated rectangular building, and (b) isolated U-shaped building; (2) Line source in a street canyon: effects of the upwind building configuration and the roof shape; (3) Line source in a city quarter (four blocks separated by two perpendicular canyons with rectangular cross-sections). For the case of a line source in a street canyon, the wind-tunnel results are compared with numerical model calculations.