Mineralogical characterization of airborne individual particulates in Beijing PM10

This work mainly focuses on the mineralogical study of particulate matter（PM10） in Beijing. Samples were collected on polycarbonate filter from April, 2002 to March, 2003 in Beijing urban area. Scanning electronic microscopy coupled with energy dispersive X-ray（SEM/EDX） was used to investigate individual mineral particles in Beijing PM10. 1454 individual mineral particulates from 48 samples were analysed by SEM/EDX. The results revealed that mineral particulates were complex and heterogeneous. 38 kinds of minerals in PM10 were identified. The clay minerals, of annual average percentage of 30.1%, were the main composition among the identified minerals, and illite/smectite was the main composition in clay minerals, reaching up to 35%. Annual average percentage of quartz, calcite, compound particulates, carbonates were 13.5%, 10.9%, 11.95%, 10.31%, respectively. Annual average percentage less than 10% were gypsum, feldspar, dolomite, and so on. Fluorite, apatite, halite, barite and chloridize zinc（ZnCl2） were firstly identified in Beijing PM10. Sulfurization was found on surface of mineral particles, suggested extensive atmospheric reaction in air during summer.

A toxicological study of inhalable particulates by plasmid DNA assay:A case study from Macao

Oxidative damage to plasmid DNA induced by airborne PM10 （particulate matter with an aerodynamic diameter of 10 μm or less） is caused by the bioavailable （i.e., soluble） heavy metals on the particle surface. However, quantitative analyses of the links between PM10 and oxidative damage are limited. In this study, plasmid DNA assay and ICP-MS were applied to study oxidative capacity and trace element compositions, respectively, of summer and winter PM10 samples collected at several sites （Sun Yat Sen Municipal Park （SYSP） and Av. de Horta e Costa （AHC） on the Macao peninsula and Macao University on Tai- pa Island （TI）） in Macao. At AHC and TI, the oxidative capacity of PM10 collected in winter was higher than that collected in summer, for both the whole sample and the water-soluble fraction. In contrast, no seasonal variation was noted at SYSP. PMI0 exhibited the highest oxidative capacity at SYSP and lowest oxidative capacity at TI in both seasons, demonstrating that the PMl0 collected on the Macao peninsula had a higher toxicity than that from Taipa Island. ICP-MS analyses revealed that the concentrations of total analyzed trace elements and their water-soluble components in PMI0 from TI and AHC were higher in winter than in summer, whereas SYSP displayed the opposite trend. The extents of oxidative damage induced by the wa- ter-soluble fractions and intact whole particles were generally similar, implying that the oxidative damage caused by particles in Macao resulted mainly from the water-soluble fraction. The oxidative capacities of PM10 were positively correlated with both whole and soluble Zn at the 95% confidence level, indicating that Zn was the major element responsible for the oxidative damage caused by particles in Macao. Other heavy metals, such as Cr, Cu, Cd, Ni, As, and Pb, also exhibited elevated concen- trations, and the potential health impacts of these metals should be considered.