胶州湾李村河口沉积物中重金属分布特征及其控制因素

对胶州湾李村河口4个站点沉积物中的酸可挥发性硫化物(AVS)以及同步提取金属元素(SEM,包括Cu,Cd,Ni,Pb和Zn)的含量进行测定,以研究重金属元素在河口海湾沉积物中的分布特征及影响其分布的因素。结果表明,J1站表层沉积物中同步提取金属含量高于其它站点;除J1站外其他站点的同步提取金属的总量随沉积物深度变化范围不大;J1站的SEM/AVS比值始终小于1,其他站点SEM/AVS比值只在沉积物浅表层大于1。此外,AVS和同步提取Fe的含量对沉积物中同步提取金属的分布有着重要影响,其他的因素如有机质的含量等也会对沉积物中同步提取金属的分布产生影响。     

Mantle-derived magmatic gas releasing features at the Rehai area, Tengchong county, Yunnan Province, China

This paper deals with the chemical and isotopic compositions of escaped gases from the Rehai geothermal area in Tengchong county of Yunnan Province. Results indicate that there is the mantle-derived magmatic intrusion in shallow crust at this area. Modern mantle-derived magmatic volatiles are being released currently in a steady stream by way of active faults. The escaped gases are mostly composed of CO₂, together with subordinate amounts of H₂S, N₂, H₂, CH₄, SO₂, CO and He. At the studied area, the north-south directed fault is the deepest, and it may be interlinked with the deep-seated thermal reservoir that would be directly recharged by the mantle-derived magmatic volatile. The He, C isotopic evidence reveals that the modern active magma beneath Rehai area may originate from the historical mantle-derived magma which caused the latest eruptive activity of volcanoes in that region.     

An analytical model for vapor‐phase volatile organic compound diffusion through landfill composite covers

One‐dimensional mathematical models for vapor‐phase volatile organic compound (VOC) diffusion through composite cover barriers are presented. An analytical solution to the model was obtained by the method of separation of variables. The results obtained by the proposed solution agree well with those obtained by a numerical analysis. Based on the proposed analytical model, the VOC breakthrough curves of five different composite covers are compared. The effects of degree of saturation of geosynthetic clay liner (GCL) or compacted clay liner (CCL) on VOC migration in the composite covers are then presented. Results show that the composite cover barriers provide much better diffusion barriers for VOC than the single CCL. The top surface steady‐state flux for a composite barrier, consisting of a 1.5 mm geomembrane (GM) and a 20 cm CCL, can be 8.3 times lower than that for a 30 cm CCL. The surface steady‐state flux for the case with (1.5 mm GM + 6 mm GCL) was found to be 2.3 times lower than that for the case with (1.5 mm GM + 20 cm CCL). The degree of saturation S_r of the CCL has a great influence on VOC migration in composite covers when S_r is larger than 0.5. The steady‐state flux at the surface of GM for the case with S_r = 0.7 can be 1.8 times lower than that for the case with S_r = 0.2. The proposed analytical model is relatively simple and can be used for verification of complicated numerical models, analysis of experimental data and performance assessment of composite cover barriers. Copyright © 2016 John Wiley & Sons, Ltd.     

Characterization and source apportionment of volatile organic compounds in urban and suburban Tianjin,China

Tianjin is the third largest megacity and the fastest growth area in China, and consequently faces the problems of surface ozone and haze episodes. This study measures and characterizes volatile organic compounds(VOCs), which are ozone precursors, to identify their possible sources and evaluate their contribution to ozone formation in urban and suburban Tianjin,China during the Ha Chi(Haze in China) summer campaign in 2009. A total of 107 species of ambient VOCs were detected,and the average concentrations of VOCs at urban and suburban sites were 92 and 174 ppbv, respectively. Of those, 51 species of VOCs were extracted to analyze the possible VOC sources using positive matrix factorization. The identified sources of VOCs were significantly related to vehicular activities, which specifically contributed 60% to urban and 42% to suburban VOCs loadings in Tianjin. Industrial emission was the second most prominent source of ambient VOCs in both urban and suburban areas, although the contribution of industry in the suburban area(36%) was much higher than that at the urban area(16%). We conclude that controlling vehicle emissions should be a top priority for VOC reduction, and that fast industrialization and urbanization causes air pollution to be more complex due to the combined emission of VOCs from industry and daily life, especially in suburban areas.     

山东地区三类典型制药企业的VOCs源成分谱及排放特征研究

制药行业因在提取等过程中使用有机溶剂排放大量挥发性有机物（VOCs）而备受关注.本研究在山东省选择化学合成、生物发酵、中药共三家制药企业开展了107种VOCs组分的监测和分析,并建立制药企业的VOCs源成分谱.研究结果表明：化学合成类和生物发酵类制药企业排放总质量浓度均超过20 mg/m³,中药制药企业的样品的平均质量浓度相对较小,为902.66 μg/m³.本研究所分析的107种组分中,以含氧挥发性有机物（OVOCs）为主,三家企业均超过75%,其中,化学合成制药类卤代烃物种的占比较高.企业类型、生产环节、收集排放措施等是影响VOCs成分的重要因素.     

餐饮源挥发性有机物(VOCs)排放特征及对臭氧生成的影响

餐饮排放是城市地区挥发性有机物（VOCs）重要的无组织来源,由于其排放特征复杂,是大气环境研究和管理的薄弱环节.本研究采用了现场和实验模拟两种采样方式,利用2,4-二硝基苯肼（DNPH）采样柱和不锈钢罐分别采集羰基化合物和全空气样品,然后利用高效液相色谱（HPLC）和气相色谱-质谱联用仪（GC-MS/FID）对116种组分进行定性定量分析.在此基础上,分析了餐饮源VOCs的排放特征及其影响因素.总体来看,含氧有机物（OVOCs）和烷烃是VOCs浓度的主要贡献者,但不同餐饮源的源谱特征差异较大.另外,通过比较发现食用油的种类、油的使用次数、加热方式、烹饪方式和调味料等因素会对餐饮源VOCs排放特征造成显著影响.进一步分析了不同菜系所排放VOCs的臭氧生成潜势（OFP）,关键组分主要是甲醛、乙醛、丁烯醛、乙烯和丙烯等.本研究成果能够补充我国餐饮源VOCs控制所需的基础数据.     

德州市冬季大气挥发性有机物污染特征及其对臭氧和二次有机气溶胶生成的贡献

利用气相色谱-质谱仪/火焰离子检测器（Online-GC-MS/FID）对2017年冬季山东德州大气中99种挥发性有机物（VOCs）进行连续测量,研究了VOCs浓度和组分特征、日变化趋势、来源及其对臭氧（O₃）、二次有机气溶胶（SOA）生成的贡献.结果表明,德州大气VOCs平均体积分数为（47.74±33.11）×10^-9,烷烃占比最大,为40.66%.总VOCs及其组分表现出早晚体积分数高、中午体积分数低的日变化规律.德州大气中丙烷、丙烯、苯及甲苯和二氯甲烷分别受到液化石油气挥发、生物质燃烧、机动车排放和溶剂使用等人为源的影响.反向轨迹模型分析发现,北方内陆气团对德州VOCs体积分数具有一定贡献.烷烃、烯烃、芳香烃的臭氧生成潜势分别为（34.87±33.60）、（120.48±118.76）和（59.77±94.14）μg/m³,乙烯、丙烯、甲苯和间/对二甲苯的贡献较大.芳香烃氧化主导了SOA生成,其贡献率为93.7%,甲苯、间/对二甲苯、苯对SOA生成的贡献最大.为解决大气复合污染问题、实现臭氧和PM_2.5协同控制,德州应重点控制甲苯、间/对二甲苯等芳香烃的排放.     

水中挥发性有机物分析的影响因素和常见问题解决办法

应用吹扫捕集-气相色谱-质谱法测定水中挥发性有机物,多种因素影响着定量分析的准确性,包括样品瓶的清洗及标准配制、样品和标准溶液的保存、载气气源的纯度、仪器状态检查及参数选择、分离度及积分方式。本文提出在分析过程中样品瓶必须清洗干净,以免污染样品;样品和标准溶液的保存时间过长会降低目标物的回收率;载气和吹扫气会带入杂质;分离度的大小将影响峰高和峰面积测量的准确度。针对分析中氯乙烯的回收、二氯甲烷的交叉污染、浑浊样品的处理等常见问题提供了解决方案,推荐采用选择扫描方式进行分析,并根据样品基体的情况来选择定量离子,将分析的初始温度降至40℃以下并保持2~3 min,以保证氯乙烯的回收率;实验室保持良好的通风环境,避免二氯甲烷交叉污染;色谱柱的最高温度升至220℃以上并保持2~3 min,可以排除萘及分子烷烃的干扰,保证分析的连续性;对于浑浊样品,推荐在野外取样时进行在线过滤或直接采用静态顶空方式进行测定。     

结合气象模式与GloBEIS模式研究气象条件对BVOCs排放的影响

BVOCs对全球碳收支、对流层化学反应及臭氧的形成和气候变化都有很大的影响.选取森林覆盖率高且BVOCs排放尚未有研究报道的中国东北地区作为研究区域,利用美国NCAR中心提供的1°×1°的6 h NCEP再分析资料,运行MM5模式,得到模拟结果,从中提取GloBEIS模型所需要的近地面层的温度、湿度、风速和云量的格点气象数据,实现了将MM5模式与GloBEIS相结合对BVOCs进行研究.研究中需要的植被种类及分布数据来自于最新的"植被信息系统"数据库,选取温度较高,太阳辐射较强,植被生长茂盛的2006年7月和2010年7月作为模拟时段,运行GloBEIS模型,对研究区域内的BVOCs的排放情况进行了估算.模拟结果与温度和云量等气象要素的分析结果表明,异戊二烯的排放速率受温度和PAR(光合有效辐射通量)的共同影响,日变化趋势显著,随着温度升高,PAR增强,异戊二烯的排放速率增大,在午后14:00左右达到最大值,之后降低.由于云量与PAR成反比,因此云量越少,异戊二烯的排放量就越高,反之,则越低;与异戊二烯不同,温度是单萜烯和其他VOC的排放的主导因素,受PAR和云量的影响较小,温度越高,排放量越大,反之,则越小.     

湖北一次冰雹天气过程的落区诊断分析和预报

利用欧洲中心和T106数值预报产品，分析常规气象资料，对湖北省1998年3月20～25日历史上罕见的连续性强对流天气过程进行诊断分析，揭示了产生强对流天气的环流形势和影响系统，并从短期角度对连续性强对流天气过程归纳出天气模型和预报指标，得出了强对流天气落区及降水性质与各要素之间的关系，为更好地提高预报强对流天气的准确率提供一定的参考。