大气超细颗粒物观测和扩散模拟研究进展

总结了近年来不同地区对不同环境下大气超细颗粒物的观测和扩散模拟研究进展。大量的观测研究结果表明,大气超细颗粒物的时空分布、组成特征、形成和成长的特性因观测地区的不同而存在很大差异,受气象因素和局部污染源的影响很大;其来源主要包括固定、移动燃烧源的直接排放和大气中颗粒成核现象,前一种来源一般是局部的,而后一种来源则是区域性的。目前,大多数关于大气超细颗粒物扩散的模拟研究都是针对其质量浓度的,对其数浓度扩散的模拟研究主要集中在小范围(机动车排放烟云的研究方面),在城市区域范围上的研究和应用还很少。最后,探讨和展望了大气超细颗粒物今后的主要研究方向和研究中面临的挑战。     

Identification of carbonaceous geosorbents for PAHs by organic petrography in river floodplain soils

Organic petrographic analysis was applied to provide direct information on carbonaceous geosorbents for PAHs in river floodplain soils. The anthropogenic OM group (primarily coal and coal-derived particles) displayed large volume amounts for all the soil samples. Distinct PAH concentrations with similar PAH distribution patterns were determined in grain size and density fractions for each sample. Two-ring PAHs had stronger correlation to organic carbon (OC) than black carbon (BC) contents, while heavier PAHs showed correlation to BC, rather than OC. In this study, we combined grain size and density separation, PAH determinations, TOC and BC measurements, and organic petrographic identification, and concluded that two-ring PAHs in soils were associated to coal particles. Other heavier PAHs could be more controlled by black carbon (BC), which were mostly coal-derived particles from former coal mining and coal industrial activity.     

Occurrence of coal and coal-derived particle-bound polycyclic aromatic hydrocarbons (PAHs) in a river floodplain soil

A PAH contaminated river floodplain soil was separated according to grain size and density. Coal and coal-derived particles from coal mining, coal industry and coal transportation activities were identified by organic petrographic analysis in our samples. Distinct concentrations of PAHs were found in different grain size and density fractions, however, similar distribution patterns of PAHs indicated similar sources. In addition, although light fractions had the mass fraction by weight of less than 5%, they contributed almost 75% of the total PAHs in the soil. PAH concentrations of all sub fractions showed positive correlation with their TOC contents. Altogether, coal and coal-derived particles that were abundant in light fractions could be the dominant geosorbents for PAHs in our samples.     

Elemental concentrations in air, water, and aquatic biota in two rural provinces in northern Vietnam

The present study on environmental pollution in northern Vietnam investigates elemental concentrations in fine particulate matter (PM_2.5), freshwater, and aquatic biota at two sites with differing levels of industrial activities. An Thin is situated 47 km east of Hanoi in the neighbourhood of a coal combustion power plant, whereas the reference site, Duy Minh, is situated in the agricultural province of Ha Nam, 40 km south of Hanoi. Elemental concentrations were analysed using energy-dispersive X-ray fluorescence, total reflection X-ray fluorescence, and graphite furnace atomic absorption spectro-metry. All investigated elements in fine particles (PM_2.5) had significantly higher concentrations in An Thin, thus identifying the air at this site as polluted. In contrast to the aerosol samples, elemental concentrations as well as quantitative differences between the sampling sites were low in freshwater and biota, indicating that the impact of atmospheric deposition was limited.     

Spatial and Temporal Comparison of Polycyclic Aromatic Hydrocarbons and Spheroidal Carbonaceous Particles in Remote European Lakes

Spheroidal carbonaceous particles (SCP) and polycyclicaromatic hydrocarbons (PAH) have been measured in the dated sediment cores of 10 remote lakes distributed across Europe. The geographic trends were evaluated by examination of the superficial sediment fluxes and total sediment inventories. The highest levels of both markers were observed in the Eastern European lakes whereas the minimal values corresponded to the lake located in the Arctic. However, this SCP-PAH correlation was not observed after exclusion of the end member lakes from the series. The temporal trends of both pollutant markers are consistent with the history of pyrolytic emissions over Europe. However, the downcore SCP distributions are shorter than the PAH profiles in nearly all lakes. The differences are probably related to the different size particle fractions involved in the measurement of each marker, >5 and >1 m for SCP and PAH, respectively. Thus, the two proxies probably reflect pollution inputs from closer (SCP) and more distant sites (PAH).     

降雨作用下坡面侵蚀的水动力机理

降雨作用下的坡面侵蚀不仅导致严重的水土流失,同时也可能诱发严重的重力地质灾害如滑坡、泥石流等.研究其发生发展的机理以及内部理论规律对减灾防灾具有至关重要的作用.文章以水动力学公式为基础,从坡面颗粒侵蚀的水分环境角度入手,分析了浸泡状态下松散颗粒和固定颗粒的侵蚀机理,揭示降雨作用下坡面水流与坡面颗粒间的相互作用关系,并给出各类型侵蚀发生所对应的临界降雨强度.最后,通过实例计算验证了理论的合理性.     

郑州空气颗粒物中PAHs的碳同位素特征及来源

研究了郑州城区空气颗粒物中多环芳烃(PAHs)的稳定碳同位素组成特征并对其来源进行了解析.气相色谱/燃烧系统/同位素质谱(GC/C/IRMS)分析表明,PAHs 的δ¹³C 值在非采暖季为-29.4‰～-23.4‰,采暖季为-30.0‰～-24.2‰,随着分子量的增大,PAHs 中 13C 降低.统计表明不同采样点的样品中的 PAHs 的δ¹³C 区别不明显(0.1‰<σ<0.8‰).两个季节中,三环和四环多芳香烃化合物荧蒽、芘和苯并(a)蒽的δ¹³C没有明显的区别,其范围为-24.5‰～-23.4‰,但是,五环和六环芳烃的δ¹³C 值有明显差异.随着分子量的增大,采暖季环境空气颗粒物中 PAHs的碳同位素比值变小的程度比非采暖季的大.采暖季的苯并(a)芘、茚并(1,2,3-cd)芘、苯并(ghi)苝的δ13C 值分别为-26.6‰、-30.0‰和-28.1‰,而非采暖季为-24.5‰、-29.4‰和-26.3‰.利用二元复合同位素模型,估算了不同季节机动车尾气和煤的燃烧对郑州城区苯并(a)芘的贡献.在非采暖季机动车尾气排放的贡献率为 70%,在采暖季贡献率为 50%,煤的燃烧对六环化合物的贡献高于机动车排放的贡献.     

爱尔兰海岸夏季空气颗粒物水溶性离子粒径分布研究

研究了爱尔兰西海岸国际海洋大气研究站夏季（2002年8月12～22日）大西洋气团颗粒物中水溶性无机离子的含量与其粒径关系.海盐成分（Cl^-、SO4^2-、Na^＋、Ca2＋、Mg^2＋、K^＋）含量在粗颗粒物中随粒径呈双峰分布（0.8～30 μm）,但Ca^2＋和K＋受陆域源影响,在亚微米颗粒区间出现另一分布峰（0.1～0.8 μm）.二次颗粒物成分在所有颗粒物中均有检出;NO^3-呈广域宽带分布,其中大部分出现在海盐主峰区（0.8～8 μm,存在Dp 1.4 μm和Dp 4.4 μm两种模态）;nss-SO4^2-（非海盐硫酸根）和NH^4＋呈相关三峰分布（Dp 0.44 μm、Dp 1.4 μm和Dp 4.4 μm）,CH3SO3-也呈相似三峰分布（Dp 0.44 μm、Dp 1.4 μm和Dp 8 μm）,三者在亚微米颗粒区间同位出现主峰.二次颗粒物成分Dp 1.4 μm模态在海岸空气颗粒物研究文献中尚少见报道.讨论了亚微米区间二次颗粒物盐类的化学形态.TSP中nss-SO4^2-、NO^3-、NH^4＋和CH3SO^3-的日均浓度分别为0.279、0.171、0.158和0.041 μg/m^3.     

水上事故溢油漂移轨迹预测模型研究与应用

近年来,国内外海上溢油事故频发,不仅造成巨额的经济损失,同时也对海洋及近岸海域生态系统造成了巨大危害,构建科学、可靠的海洋溢油模型对于溢油事故的处置应对、预警预报都具有十分重要的科学和现实意义。基于EFDC（Environmental Fluid Dynamic Code）、＂油粒子＂溢油轨迹和风化模型,构建了海上事故溢油漂移轨迹预测模型。通过对实际溢油事故的模拟对比证明,相对于基于对流扩散方程的传统溢油模型,＂油粒子＂算法更直观,模拟的油膜轨迹、形态更贴近实际过程。     

雾霾的产生机理及防治对策措施研究

雾霾是雾和霾的混合物,通过分析雾与霾产生的条件及产生机理,得出导致中国中东部产生雾霾的条件及原因是：空气湿度接近饱和、大气层结稳定、存在冷却条件及大量霾粒子。由于雾霾产生的条件中天气及气候因素目前人类难以控制,因此提出防治雾霾的关键是要控制目前受人类影响的霾离子的防治思路。结合国内外防治雾霾经验,提出中国防控雾霾的对策措施：污染源控制与治理措施、建立区域联防联控机制、完善和推进企业清洁生产制度、倡导绿色生活理念、建立霾预警制度、制定应急方案、研发新技术等。