title: Seasonal variation of particle-induced oxidative potential of airborne particulate matter in Beijing.
abstract: An in vitro plasmid scission assay (PSA), the cell apoptosis assay, and ICP-MS were employed to study the oxidative potentials and trace element compositions of the airborne particulate matter (PM) in Beijing during a one year-long field campaign from June 2010 to June 2011. The cell damages induced by PM reveled by the cell apoptosis assay showed a similar variation pattern to the DNA damages obtained by PSA, verifying the feasibility of the PSA in analyzing the oxidative capacity of PM samples. The PSA experiments showed that the particle-induced DNA damage was highest in summer, followed by spring, winter and autumn in descending order. The percentages of the oxidative damages to plasmid DNA induced by the water-soluble fractions of PM under the particle doses from 10 to 250μg/ml were generally lower than 45%, with some values peaking at above 50%. The peak values were frequently present in late spring (i.e. April and May) and early summer (i.e. June) but they were scarcely observed in other seasons. These peak values were mostly associated with haze days or the days with low wind speed (less than 4m/s), indicating that the PM samples during haze had higher oxidative potential than those during non-haze periods. The oxidative potential induced by the water-soluble fraction of the PM displayed a significant positive correlation with the concentrations of the water-soluble elements Cd, Cs, Pb, Rb, Zn, Be and Bi, demonstrating that the particle-induced oxidative potentials were mainly sourced from these elements. The exposure risk represented by the mass concentration of these elements in unit volume of atmosphere was higher in summer and winter, and lower in autumn and spring. The haze day PM samples not only had higher level of oxidative potentials but also had higher concentrations of water-soluble elements.
authors.affiliation: State Key Laboratory of Coal Resources and Safe Mining, School of Geoscience and Surveying Engineering, China University of Mining and Technology (Beijing), Beijing 100083, China. Electronic address: shaoL@cumtb.edu.cn.
authors.forename: Longyi
authors.initials: L
authors.lastname: Shao
authors.affiliation: State Key Laboratory of Coal Resources and Safe Mining, School of Geoscience and Surveying Engineering, China University of Mining and Technology (Beijing), Beijing 100083, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Hu
authors.affiliation: Institute of Meteorology and Climate Research, Atmospheric Environmental Research (IMK-IFU), Karlsruhe Institute of Technology (KIT), 82467 Garmisch-Partenkirchen, Germany.
authors.forename: Rongrong
authors.initials: R
authors.lastname: Shen
authors.affiliation: Institute of Meteorology and Climate Research, Atmospheric Environmental Research (IMK-IFU), Karlsruhe Institute of Technology (KIT), 82467 Garmisch-Partenkirchen, Germany.
authors.forename: Klaus
authors.initials: K
authors.lastname: Schäfer
authors.affiliation: State Key Laboratory of Coal Resources and Safe Mining, School of Geoscience and Surveying Engineering, China University of Mining and Technology (Beijing), Beijing 100083, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Coal Resources and Safe Mining, School of Geoscience and Surveying Engineering, China University of Mining and Technology (Beijing), Beijing 100083, China.
authors.forename: Jianying
authors.initials: J
authors.lastname: Wang
authors.affiliation: HICE - Helmholtz Virtual Institute of Complex Molecular Systems in Environmental Health - Aerosols and Health, and Joint Mass Spectrometry Centre, Cooperation Group Comprehensive Molecular Analytics, Helmholtz Zentrum München, 85764 Neuherberg, Germany.
authors.forename: Jürgen
authors.initials: J
authors.lastname: Schnelle-Kreis
authors.affiliation: HICE - Helmholtz Virtual Institute of Complex Molecular Systems in Environmental Health - Aerosols and Health, and Joint Mass Spectrometry Centre, Cooperation Group Comprehensive Molecular Analytics, Helmholtz Zentrum München, 85764 Neuherberg, Germany; Joint Mass Spectrometry Centre, Chair of Analytical Chemistry, University of Rostock, 18055 Rostock, Germany.
authors.forename: Ralf
authors.initials: R
authors.lastname: Zimmermann
authors.affiliation: School of Biosciences, Cardiff University, Museum Avenue, Cardiff CF10 3AX, UK.
authors.forename: Kelly
authors.initials: K
authors.lastname: BéruBé
authors.affiliation: Institute of Meteorology and Climate Research, Atmospheric Environmental Research (IMK-IFU), Karlsruhe Institute of Technology (KIT), 82467 Garmisch-Partenkirchen, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Suppan
keywords: Beijing; Haze; Oxidative potential; Particulate matter (PM); Plasmid scission assay (PSA); Water-soluble element