A review of noise modelling software used in Hong Kong

Noise assessment is an important component of the Environmental Impact Assessment process. In Hong Kong, the government officials and consultants have been relying on specialised software to evaluate the likely impacts upon residents due to the noise emitted from potential stationary and/or moving sources. In this paper, we reviewed noise modelling software that are commonly used in Hong Kong and identified their noise calculation algorithms. The software normally includes a source term and simplified noise propagation model. The source term is either entered as an input by a user or estimated based on the empirical formula derived from noise measurements back to the 70s and 80s whereas noise propagation model is derived based on the wave (or ray) theory and includes air absorption, ground reflection, etc. However, the built environment in a modern city like Hong Kong would hamper the applicability of noise modelling software due to the source terms derived in the past do not represent the noise levels emitted from the sources we have now, and the simplified propagation model does not consider the complex geophysical characteristics of the built environment in three-dimension. The paper concludes with some practical implications and suggestions for future development.