On the sources of suspended particulate in Hong Kong

This paper presents a summary and a preliminary interpretation of the mass concentrations and the major chemical compositions of the TSP and RSP in Hong Kong for year 1994. The particulate levels in many urban locations are high with respect to the Air Quality Objective (AQO) of Hong Kong. Carbonaceous materials (mainly elemental carbon), secondary pollutants such as sulfate and nitrate, and crustal compounds are the major components of the particulate matter. The presence of carbon-rich particles in Hong Kong should be a concern as they may be more harmful to human health (as compared to soil-derived particles). The seasonal trends in mass concentration and the composition of the particulate can be explained in terms of the seasonal differences in large-scale meteorology, amount of energy used, and possible transport of dust from outside to Hong Kong. Two case studies are presented to illustrate the difference in chemical signatures of the RSP samples. The urban aerosol data are briefly compared with that from a non-urban coastal location in Hong Kong.