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Abstract: Based on environmental monitoring data in 93 major cities and meteorological records at 398 weather stations in China from 1981 to 2007, total suspended particle (TSP) concentration, the intensity of dustfall, and sand and dust storm frequency (Fd) were analysed. During the past 27 years, the annual average TSP concentration (CTSP) in 93 cities was 402 μg m−3. Annual average CTSP decreased from the north to the south and from inland to the coast areas with a peak value of 628.8 μg m−3 in Lanzhou. In the 1980s, 1990s and 2000s, annual average CTSP was 628.7, 319.2, and 250.1 μg m−3, respectively. Annual average intensity of dustfall (Id) was 240.5 t km−2 a−1, decreased from northern to southern China and from inland to the coast areas with the maximum value of 717.2 t km−2 a−1 in Baotou. In the 1980s, 1990s and 2000s, annual average Id was 334.8, 220.9, 146 t km−2 a−1 respectively. Annual average Id in the Loess Plateau region was commonly higher than 200 t km−2 a−1. The annual average Fd decreased from arid regions in northwestern China to humid areas in southeastern China with two sand and sand storm centers existing in Xinjiang Taklamakan Desert and western Inner Mongolia. The annual average Fd in the 1980s, 1990s, 2000s was 16, 8, 6 days respectively, decreased steadily from 18 days in 1981–5 days in 2007. Annual average Id had a positive linear relation to annual average CTSP (R 2 = 0.96). Annual average Fd had a positive relation with annual average CTSP (R 2 = 0.97) as well as annual average Id (R 2 = 0.94). TSP was the chief pollutant influencing Air Pollution Index (API) in northern China in spring and winter seasons. Sand and dust storm might be a major factor affecting the temporal variability and spatial distribution of TSP and dustfall in China. [Copyright &y& Elsevier]

Deep placement of nitrogen fertilizer affects the fate of fertilizer nitrogen through influencing nitrogen transformation. Few studies have examined ammonia (NH 3 ) volatilization and nitrogen-utilization efficiency under deep placement of nitrogen fertilizers in no-tillage (NT) paddy fields. Therefore, a field experiment was conducted to investigate the different application methods of nitrogen fertilizers [no fertilizer, traditional nitrogen broadcasting (S), and point deep placed at 5 cm, 10 cm and 20 cm depths as basal fertilizer + nitrogen broadcasting as topdressing (e.g., 5D, 10D and 20D)] on NH 3 volatilization, nitrogen recovery efficiency (NRE), nitrogen partial factor productivity (NPFP), nitrogen agronomic efficiency (NAE), and grain yield in NT paddy fields during the 2012–2013 rice growing seasons in central China. Nitrogen deep placement significantly decreased mean floodwater pH by 2–4% and mean floodwater NH 4 + –N concentration by 29–98% compared with nitrogen broadcasting. Nitrogen deep placement treatments significantly decreased cumulative NH 3 volatilization by 20–45% in 2012 and by 15–40% in 2013 compared with S treatment. On average, nitrogen deep placement treatments significantly increased NRE by 26–93%, NPFP by 10–16%, NAE by 31–51%, and grain yield by 5–11% in both seasons compared with S treatment. In addition, 10D treatment showed the highest nitrogen utilization efficiency and grain yield, implying that this measure can be effective in increasing agricultural economic viability and decreasing NH 3 volatilization. However, given high labor requirement for manual deep placement, developing mechanical fertilization technology is necessary to overcome this difficulty in future. [ABSTRACT FROM AUTHOR]

Abstract: In this study, an interval full-infinite mixed-integer municipal-scale energy model (IFMI-MEM) is developed for planning energy systems of Beijing. IFMI-MEM is based on an integration of existing interval-parameter programming (IPP), mixed-integer linear programming (MILP) and full-infinite programming (FIP) techniques. IFMI-MEM allows uncertainties expressed as determinates, crisp interval values and functional intervals to be incorporated within a general optimization framework. It can also facilitate capacity-expansion planning for energy-production facilities within a multi-period and multi-option context. Then, IFMI-MEM is applied to a real case study of energy systems planning in Beijing. The results indicate that reasonable solutions have been generated. They are helpful for supporting (a) adjustment of the existing demand and supply patterns of energy resources, (b) facilitation of dynamic analysis for decisions of capacity expansion and/or development planning, and (c) coordination of the conflict interactions among economic cost, system efficiency, pollutant mitigation and energy-supply security. [Copyright &y& Elsevier]

Abstract: This study aims to investigate the characteristics, provenance, and particle-related pollution of an intense dustfall event that occurred in Beijing on 16–17 April 2006. Satellite images reveal that the aeolian dust originated in northeastern Alxa League of Inner Mongolia and passed southeastward across northern Ningxia, middle Inner Mongolia, northern Shaanxi, Shanxi, and Hebei provinces. The dust then moved out of continental China in the vicinity of Beijing and Tianjin. The floating dust led to severe air pollution in Huhhot, Datong, and Beijing. We measured dustfall by collecting dust samples, investigated particle morphology, and calculated the mass medium diameter (MMD) of the dustfall using a scanning electron microscope (SEM). Major elements and mineral content of the dust particles were determined by electron probe and powder X-ray diffractometer, respectively. The relative abundance of dustfall during this event was 12.5–15.0gm−2, making up about 10% of the total annual dustfall in Beijing. Dustfall amounted to 205 thousand tons in Beijing, the largest amount observed in recent years. The dust particles were mostly angular, subangular and subrounded in morphology, and the MMD was nearly 12μm. Particles <10μm accounted for 54.7% by number, but fine sand particles (larger than 50μm) made up 53.7% by volume. Particles with diameters larger than 20μm made up of the predominant volume of the samples (90.35%). Hence, this dustfall event was characterized by a high content of fine sand and coarse silt particles. The principal elements in the dust particles were C, O, Si, Al, Fe, and Ca, whereas the major minerals were quartz, Na-feldspar, calcite, and clay minerals. [ABSTRACT FROM AUTHOR]