Assessment of pollutant dispersion in the re-entrance space of a high-rise residential building, using wind tunnel simulations

This paper investigates the likely route of dispersion of airborne pollutants and pathogenic agents in the re-entrance space of a high-rise residential (HRR) building in Hong Kong. A 1 : 150 scaled HRR building, a 30 storeys tall model was tested in a wind tunnel with simulated atmospheric boundary layer flow. Tracer gas, propane released from the lower, middle and upper parts of the building, was measured by flame ionisation detection and this was used to simulate the air pollutant dispersion within the re-entrance space. There were a total of 495 measurements, tested under five different wind directions at 99 measurement points on windows locations of every floor of the modelled building. The tracer gas concentration profiles obtained would illustrate the pollutant dispersion and transmission routes under the different wind effect. The results showed that the airborne pollutants or pathogenic agents could be dispersed mainly along the vertical routes, posing a potential risk to the adjacent neighbours immediately above the source location. Wind direction could also affect the dispersion. The findings of this study should inform the development of ventilation strategies for HRR buildings and would guide building design to minimise transmission of airborne diseases or harmful pollutants within buildings.