ACPD Atmospheric Chemistry and Physics Discussions ACPD 1680-7375 Copernicus GmbH Göttingen, Germany 10.5194/acpd-6-6467-2006 A physical modeling approach for identification of source regions of primary and secondary air pollutants Lo J. C. F. 1 Lau A. K. H. 2 3 Yuan Z. B. 1 Fung J. C. H. 3 Chen F. 4 Atmospheric, Marine and Coastal Environment Program, The Hong Kong University of Science and Technology, Hong Kong, P. R. China Environmental Central Facility, Institute for the Environment, The Hong Kong University of Science and Technology, Hong Kong, P. R. China Department of Mathematics, The Hong Kong University of Science and Technology, Hong Kong, P. R. China National Center for Atmospheric Research, Boulder, Colorado, USA 13 07 2006 6 4 6467 6496 This is an open-access article ditributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. This article is available from http://www.atmos-chem-phys-discuss.net/6/6467/2006/acpd-6-6467-2006.html The full text article is available as a PDF file from http://www.atmos-chem-phys-discuss.net/6/6467/2006/acpd-6-6467-2006.pdf

This paper describes a simple but practical methodology to identify the contribution of primary and secondary air pollutants from the local/regional emission sources to Hong Kong, a highly urbanized city with complex terrain and coastlines. The meteorological model MM5 coupled with a three-dimensional, mutli-particle trajectory model is used to identify salient aspects of regional air pollutant transport characteristics during some typical meteorological conditions over the Pearl River Delta (PRD) region. Several weighting factors are determined for calculating the air mass/pollutant trajectory and are used to evaluate the local and regional contribution of primary pollutants over the PRD to Hong Kong pollution. The relationships between emission inventories, physical paths and chemical transformation rates of the pollutants, and observational measurements are formulated. The local and regional contributions of secondary pollutants are obtained by this conceptual module under different weather scenarios. Our results demonstrate that major pollution sources over Hong Kong come from regional transport. In calm-weather situations, 78% of the respirable suspended particulates (RSP) totals in Hong Kong are contributed by regional transport, and 49% are contributed by the power plants within the PRD. In normal-day situations, 71% of the RSP are contributed by regional transport, and 45% are contributed by the power plants.