The aim of this study is to predict the concentration distribution of air pollution emitting from sources near the ground within urban area. This study consists of field measurements and wind tunnel experiments. The field measurements were conducted at Ikegami-Shinmachi area in Kawasaki in vicinity of Tokyo using SF6 as the tracer gas. Metroporitan Expressway is licated along SW-NE diagonal of the study area around Ikegami-Shinmachi intersection. There is the local higyway running parallel to the expressway and the local road cross to them. Diffusion fields were simulated in a thermally stratified wind tunnel at the IIS. The city model was modeled partially at a scale of 1:600. The dispersion of emission from a line source near the ground, a ethylene was used as the tracer gas. The results of the wind tunnel experiments showed good agreement with the results of the field measurements.
