Modelling the effects of neighbourhood and street geometry on pedestrian thermal comfort in Hong Kong

Abstract

The severe global warming and rapid urbanization increase the risks of extreme heat stresses for pedestrians. While urban geometry significantly affects pedestrian thermal comfort, limited research has explored the relative impacts of street and neighbourhood design. ENVI-met simulation models were constructed to analyse their effects on pedestrian thermal comfort in an urban street of Hong Kong. Subsequent ANOVA analysis revealed that surrounding building height was a major contributor to thermal comfort variations of a street in addition to street orientation and aspect ratio, while tree coverage ratio and ground albedo played much weaker roles. Based on these, a multivariate model has been developed to predict hourly street thermal conditions for various street orientations, aspect ratios and surrounding building heights. Specific preferred and avoided street configurations for optimizing the thermal environment have been identified. For instance, aspect ratio ≥ 5.0 is preferred for NW-SE Street with surrounding building height of 45–105 m.