Air pollution problems, such as reentry of exhaust fumes into buildings and pollution of residential areas near sources of emission, are of much concern. In this study, wind tunnel simulation of diffusion of high temperature fumes from a point source in the lower portion of a building was carried out. Concentrations near the building surfaces and at the ground level around the building were predicted. A method was also proposed to estimate the yearly-average concentration based on the dilution ratio obtained from the wind tunnel simulation and meteorological data for the area in consideration. High concentrations were predicted for one of the building walls close to the source and in the building wake. For one location on the ground, mean concentrations as high as 0.32×10^<-3> times the source concentration were predicted.