The Hong Kong Polytechnic University , Hong Kong

Professor Xiang-dong Li is Chair Professor of Environmental Science and Technology at Department of Civil & Environmental Engineering, Associate Dean (Research) of Faculty of Construction and Environment, The Hong Kong Polytechnic University...

... He obtained his BSc in Earth Sciences and his MSc in Geochemistry from Nanjing University, and his PhD in Environmental Technology from Imperial College London. Prof. Li’s major research interests include regional pollution, urban environmental studies, and remediation of contaminated soils. He has published more than 190 papers in leading international journals, and is one of the highly cited researchers in Environment/Ecology of the Web of Science database. He was awarded the Outstanding Young Researcher (Oversea) Fund from the Natural Science Foundation of China (NSFC) in 2007. Professor Li is the past president (2011-2013) of the International Society of Environmental Geochemistry and Health (SEGH). He is currently an Associate Editor for Environmental Science and Technology (ES&T). Prof. Li is also an associate editor and editorial board member for several other international journals in related research fields.



Differential Toxicities and Contributing Chemicals in Urban PM2.5 of China

Xiangdong Li1, Ling Jin1, Jiawen Xie1, Chris K.C. Wong2, Serena K.Y. Chan2, Gülcin Abbaszade3 Jürgen Schnelle-Kreis3, Ralf Zimmermann3,4, Jun Li5, Gan Zhang5, Pingqing Fu6

1Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong

2Croucher Institute for Environmental Sciences, Department of Biology, Hong Kong Baptist University, Kowloon Tong, Hong Kong

3Joint Mass Spectrometry Centre, Comprehensive Molecular Analytics, Helmholtz Zentrum München (HMGU/CMA), 85764 Neuherberg, Germany

4Joint Mass Spectrometry Centre, Chair of Analytical Chemistry, University of Rostock (UR/IC), 18059 Rostock, Germany

5State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China

6Institute of Surface-Earth System Science, Tianjin University, Tianjin 300072, China


The emerging evidence throws into question the assumption that particles are equally toxic – an assumption that underlies the quantitative attribution of global premature deaths to outdoor fine particulate matter (PM2.5) pollution. This study tested the hypothesis that the toxicological properties per unit mass concentration of PM2.5 vary among geographically distinct areas where toxic component mixtures of PM2.5 differ. We compared the in vitro toxic potencies of wintertime PM2.5 from Beijing and Guangzhou, two contrasting megacities in China. A concentration-effect analysis for cytotoxicity and intracellular reactive oxygen species (ROS) in human bronchial epithelial cells exposed to PM2.5 from the two cities revealed significantly greater toxic potencies of PM2.5 from Beijing at equal mass concentrations. A targeted chemical analysis showed that the burden of metals and polycyclic aromatic hydrocarbons (PAHs) per unit mass of PM2.5 was significantly higher in Beijing than in Guangzhou. Mixture toxicity experiments demonstrated the additive effects of metals and PAHs on ROS generation, supporting the quantitative attribution of these chemicals to PM2.5-induced effects. On average, 38% and 24% of the mixture effects of the PM2.5 from Beijing and Guangzhou, respectively, were explained by the identified chemicals. PAHs contributed approximately twice the share of the PM2.5 mixture effects than did metals. Fe, Cu, and Mn were the dominant metals, constituting >80% of the metal-shared effects. Dibenzo[a,l]pyrene alone explained >65% of the PAH-shared effects. The significant contribution from coal combustion and vehicular emissions in Beijing underlies the major source disparities of toxicologically active PAHs between the two cities. Our study provided novel quantitative insights into the role of varying toxic component profiles in shaping the differential toxic properties of city-specific PM2.5 pollution.