1. Division of Environment; Hong Kong University of Science and Technology; Kowloon Hong Kong
2. Now at School of Engineering and Applied Science; Harvard University; Cambridge Massachussetts USA
3. Department of Chemistry; Hong Kong University of Science and Technology; Kowloon Hong Kong
4. Environmental Protection Department; Wan Chai Hong Kong
5. Department of Chemical and Biomolecular Engineering; Hong Kong University of Science and Technology; Kowloon Hong Kong