Minimising the ingress of external pollution into urban buildings.

To develop guidance on effective ventilation strategies for buildings located in urban areas, it is necessary to have an understanding of the processes involved in the ingress of external pollution into buildings and its effect on indoor air quality. For naturally ventilated buildings, the combination of pressure forces and contaminant levels around the building is important in generating the level of internal contamination. Thus regions of high external pressures combined with high external pollutant concentrations will give regions of high probable ingress of contaminants and hence lead to greater internal pollutant concentrations. In this paper, results are given of the wind tunnel studies carried out at BRE to determine common regions of high contaminant levels and pressures on the surfaces of buildings, both in isolation and within arrays of urban structures. The implication of the measurements in developing low-energy ventilation strategies for buildings in urban areas are briefly discussed.