3D built-environment attributes and household road traffic noise exposure in Hong Kong

Road traffic noise is an environmental health hazard in Hong Kong and other high-density cities. The dense built environment modifies noise propagation, reflects, absorbs or diffracts sound depending on building morphology, road configuration, and open space layout, etc. Mitigation of urban traffic noise is of growing concerns to planning and design practitioners. Existing assessment methods are limited in reliably accounting for localized variations in noise exposure associated with a high-density city. The aim of this research is to 1) develop a 3D database of road traffic noise exposure for a large number of households in a high-density city; 2) explore the linkages between built environment attributes and road traffic noise exposure. A 3D built environment database was constructed for Hong Kong using building geometries, topography and urban traffic noise data. Window coordinates for each household were extracted using address and building floor plans. Computer simulation was conducted to determine traffic noise exposure at window locations using CadnaA for a random sample of 8,158 households across the city. Results revealed that 76.3% of the households are exposed to excessive road traffic noise by WHO standards. Household traffic noise exposure are significantly associated with proximity to secondary road, story-level of the flat, and other urban form attributes. The 3D database is of value for public health research in relation to noise and urban noise mitigation measures. The next step is to develop an efficient and reliable simulation tool to support planning and design decisions in traffic noise mitigation. (paper)