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Taiyuan, the capital of Shanxi province, China, is one of the most polluted cities in the world. To characterize the ambient particulate pollution, samples of particulates with aerodynamic diameter less than 10 µm (PM10) were collected during a 6-day campaign. Individual particles were analyzed by Scanning Electron Microscope with Energy-Dispersive Spectrometer (SEM-EDS) to determine their chemical composition. Meanwhile, photomicrographs were obtained from SEM to aid in particles’ source identification. The lumped data from SEM-EDS were subjected to hierarchical cluster analysis (HCA) to sort out particle types chemically. HCA combined with SEM photomicrographs allowed us to identify 20 different particle types, namely (in order of particle frequency), soil/fly ash particles, coal-burning, sulfur-rich, and iron-rich particles, gypsum, syngenite, quartz, cement, silicon sulfide, siliconferro alloy, calcium-rich particles, ferrochromium alloy, ammonium sulfate and chloride, iron-zinc, ammonium chloride, molybdenum-rich, potassium sulfate, dolomite, lead sulfate, and copper-rich particles. Their possible origins and pathways are suggested. The majority of the particles seem to originate from coal combustion, which conforms to Taiyuan’s industrial structure.

Spatial variations in phosphorus (P) fractionation, sediment geochemistry, and sorptive properties for P are assessed to test the hypothesis that these sediment properties vary within the lake and are governed by different land uses in the watershed. The dynamic equilibrium between P in sediment and water is investigated using sorption-desorption isotherms. Sediments in the littoral zone were rich in iron (Fe), aluminium (Al), and clay material in comparison to sediments from the lake proper and thus had better abilities to sorb and retain P. In the limnetic zone, there was an increasing abundance of primary minerals, and the fraction of apatite-P was high, while the level of total P was low. The amount of labile adsorbed P (LAP) in the littoral sediments varied because of contrasting land use in the sub-catchments draining into different parts of the lake. Sediments in areas where forest streams enter the lake contained significantly more LAP than sediments in areas impacted by agricultural influenced streams. Internal P loading from sediments predominantly originating from forest streams is mainly governed by sediment resuspension. The dominant P pool in sediments near the inlets of agriculturally influenced streams was non-apatite inorganic P, of which the Fe-bound is a potentially important source of P under anoxic conditions.

To characterise the water-soluble inorganic components of PM(10) in the urban area of Sheffield, size-resolved aerosol samples were collected using an electric low pressure impactor (ELPI) during a 13-day sampling campaign in October and November 2006. Cl(-), NO(3)(-), SO(4)(2-), and NH(4)(+) were determined by ion chromatography, and Na(+), K(+), Mg(2+), and Ca(2+) by inductively coupled plasma-mass spectrometry. Back trajectories analyses revealed that the air masses could be classified into two main groups. In the "maritime regime", the air masses moved mostly over the sea and just short distances (ca. 100 to 150 km) over land; in the "terrestrial regime", the air masses had moved long distances (ca. 300 to 600 km) over land before reaching the sampling site. The chemical composition of the particles was strongly influenced by the origins of the air masses. Air mass belonging to the maritime regime brought more sea-salt species such as Na(+), Cl(-), and Mg(2+). Air mass belonging to the terrestrial regime carried more K(+) and secondary components like SO(4)(2-), NO(3)(-), and NH(4)(+). Sulfate showed bimodal distribution, peaking both in the fine mode (particle size <0.96 microm) and the coarse mode (particle size >0.96 microm). Nitrate exhibited a bimodal distribution in the terrestrial regime but only a coarse mode in maritime regime. Ammonium displayed a unimodal size distribution, peaking in the fine size range, mainly bound to sulfate and nitrate. In the maritime regime, chloride showed a unimodal distribution, peaking in the coarse size range. In the terrestrial regime, chloride appeared to be bimodal with one peak in the fine mode, reflecting the presence of chloride sources from industries, and another one in the coarse mode, mainly from sea spray. Although in general the air mass trajectories can be grouped into "maritime" and "terrestrial" regimes, the results suggest that air masses reaching Sheffield have been impacted by both maritime and terrestrial sources.