熔融包裹体研究的最新进展

介绍了获取结晶质熔融包裹体化学成分的最新方法,讨论了影响熔融包襄体化学成分的因素,并在前人研究资料基础上总结了各类岩浆熔体中H2O、CO2、Cl、F和S等主要挥发分含量及其演化趋势方面的信息.     

吹扫捕集-气相色谱-质谱联用法测定地下水中27种挥发性有机物

建立了DB-624和DB-FFAP双柱定性,吹扫捕集-气相色谱-质谱联用法测定地下水中卤代烃、苯系物、氯代苯等27种挥发性有机物的分析方法。考虑到环境介质的复杂性及干扰的不确定性,选择DB-624柱和极性较强的DB-FFAP柱优化了分离条件;采用分流进样模式,确定了目标组分灵敏度较高时的分流比10∶1;选择离子监测(SIM)方式扫描,提高了各扫描周期内组分的灵敏度;DB-624和DB-FFAP双柱定性,确保了结果的准确性,在DB-FFAP柱上可实现间二甲苯和对二甲苯异构体的完全分离。方法检出限为0.02～0.10μg/L,基体加标回收率为93.3%～109.5%,精密度(RSD,n=7)为0.9%～8.5%。对外部监控样品和实际水样进行测定表明,方法准确,灵敏可靠,可以满足地下水中痕量挥发性有机物的分析要求,适合于批量样品分析。     

生物挥发性有机物研究进展

生物挥发性有机物(BVOCs)作为大气中的一种痕量气体,积极参与着大气中各类化学反应。植物BVOCs排放的影响机制,以及BVOCs与大气其他化学成分之间的反馈作用是目前全球变化研究的热点内容之一。描述了BVOCs的排放机理及其排放控制因子;综述了近年来BVOCs地表观测试验和计算方法的研究进展以及植被BVOCs排放的模拟研究现状,并对BVOCs研究的不足和发展趋势作了进一步讨论。     

An Atmospheric Chemistry Interpretation of Mass Scans Obtained from a Proton Transfer Mass Spectrometer Flown over the Tropical Rainforest of Surinam

Data on a variety of organic gases are presented, obtained with a protontransfer mass spectrometer (PTR-MS) operated during the March 1998 LBA/CLAIREairborne measurement campaign, between 60 and 12500 m over the rainforest inSurinam (2° N–5° N, 54° W–57° W). The instrumentcan detect molecules with a proton affinity greater than water, includingalkenes, dialkenes, carbonyls, alcohols, and nitriles. Many such molecules areemitted from the rainforest (e.g., isoprene) or formed from the oxidation ofprimary emissions (e.g., methylvinylketone (MVK) and methacrolein (MACR)).From a comparison with modelled data; the variation with altitude; previouslyreported biogenic emissions and the time and location of the measurement,possible and probable identities for the significant masses encountered in therange 33–140 amu have been deduced.The main observed protonated masses, postulated identities and observedaverage boundary layer mixing ratios over the rainforest were: 33 methanol(1.1 nmol/mol); 42 acetonitrile (190 pmol/mol); 43 multiple possibilities (5.9nmol/mol), 45 acetaldehyde (1.7 nmol/mol), 47 formic acid (not quantified);59 acetone (2.9 nmol/mol), 61 acetic acid (not quantified), 63 dimethylsulphide (DMS) (289 pmol/mol), 69 isoprene (1.7 nmol/mol), 71 MVK + MACR (1.3nmol/mol), 73 methyl ethyl ketone (1.8 nmol/mol), 75 hydroxyacetone (606pmol/mol), 83 C₅ isoprene hydroxy carbonylsC₅H₈O₂, methyl furan, and cis 3-hexen-1-ol(732 pmol/mol), 87 C₅ carbonyls and methacrylic acid, 95 possibly2-vinyl furan (656 pmol/mol), 97 unknown (305 pmol/mol), 99 cis hexenal (512pmol/mol) and 101 isoprene C₅ hydroperoxides (575 pmol/mol). Somespecies agreed well with those derived from an isoprene only photochemicalmodel (e.g., mass 71 MVK + MACR) while others did not and were observed athigher than previously reported mixing ratios (e.g., mass 59 acetone, mass 63DMS). Monoterpenes were not detected above the detection limit of 300pmol/mol. Several species postulated are potentially important sources ofHO_x in the free troposphere, e.g., methanol, acetone, methyl ethylketone, methyl vinyl ketone and methacrolein.     

春季长江口及其邻近海域海水和大气中CH3I、CH2Br2和CHBr3的浓度分布与海-气通量

测定了2018年春季长江口及其邻近海域海水和大气中碘甲烷(Iodomethane,CH₃I)、二溴甲烷(Dibromomethane,CH₂Br₂)和溴仿(Tribromomethane,CHBr₃)的浓度,研究其在海水和大气中的浓度分布特征,探讨了环境因素对其源汇和浓度分布的影响。调查海域海水中CH₃I、CH₂Br₂和CHBr₃的浓度分别为(5.76±2.50)、(5.38±3.31)和(4.65±3.50)pmol·L^-1,总体呈现出近岸高,远岸低的趋势。调查海域CH₃I的浓度分布受浮游植物的影响显著;CH₂Br₂的分布是多种因素共同作用的结果,其中人为输入是影响CH₂Br₂浓度分布的重要因素之一;CHBr₃的浓度分布受人为输入和浮游植物产生释放的共同影响。垂直方向上,海水上下混合比较均匀,受长江冲淡水和沉积物释放的影响,CH₃I、CH₂Br₂和CHBr₃在表层和底层都观测到浓度高值。大气中CH₃I、CH₂Br₂和CHBr₃浓度分别是(1.06±0.77)、(1.72±1.22)和(1.97±2.12)pptv,总体上呈现近岸高于远岸的趋势,人为排放、海-气交换和气团活动共同影响了大气中挥发性卤代烃(Volatile halocarbons,VHCs)的浓度分布,大气中的CH₂Br₂和CHBr₃存在多种来源,不同来源之间CH₂Br₂和CHBr₃排放比率存在较大差异。CH₃I、CH₂Br₂和CHBr₃的海-气通量分别为(50.21±45.47)、(-1.76±77.43)和(-37.65±87.07)nmol·(m²·d)^-1,表明调查期间长江口及其邻近海域是CH₃I的源,同时也是CHBr₃和CH₂Br₂的汇。     

Modeling BVOC isoprene emissions based on a GIS and remote sensing database

This paper presents a geographic information systems (GIS) model to relate biogenic volatile organic compounds (BVOCs) isoprene emissions to ecosystem type, as well as environmental drivers such as light intensity, temperature, landscape factor and foliar density. Data and techniques have recently become available which can permit new improved estimates of isoprene emissions over Hong Kong. The techniques are based on Guenther et al., 1993, Guenther et al., 1999 model. The spatially detailed mapping of isoprene emissions over Hong Kong at a resolution of 100 m and a database has been constructed for retrieval of the isoprene maps from February 2007 to January 2008. This approach assigns emission rates directly to ecosystem types not to individual species, since unlike in temperate regions where one or two single species may dominate over large regions, Hong Kong's vegetation is extremely diverse with up to 300 different species in 1 ha. Field measurements of emissions by canister sampling obtained a range of ambient emissions according to different climatic conditions for Hong Kong's main ecosystem types in both urban and rural areas, and these were used for model validation. Results show the model-derived isoprene flux to have high to moderate correlations with field observations (i.e. r² = 0.77, r² = 0.63, r² = 0.37 for all 24 field measurements, subset for summer, and winter data, respectively) which indicate the robustness of the approach when applied to tropical forests at detailed level, as well as the promising role of remote sensing in isoprene mapping. The GIS model and raster database provide a simple and low cost estimation of the BVOC isoprene in Hong Kong at detailed level. City planners and environmental authorities may use the derived models for estimating isoprene transportation, and its interaction with anthropogenic pollutants in urban areas.     

Effect of Resuspension on the Release of Heavy Metals and Water Chemistry in Anoxic and Oxic Sediments

Two types of river sediments with contrasting characteristics (anoxic or oxic) were resuspended and the release of heavy metals and changes in water chemistry were investigated. During resuspension of the anoxic sediment, the dissolved oxygen (DO) concentration and redox potential of the water layer decreased abruptly within the first 1 min, followed by increases toward the end of the resuspension period. Heavy metals were released rapidly in the first 6 h, probably due to the oxidation of acid volatile sulfide (AVS) of the anoxic sediment, and then the aqueous phase concentrations of the heavy metals decreased due to resorption onto the sediment until the 12‐h point. During resuspension of the oxic sediment, the DO concentration and redox potential remained relatively constant in the oxic ranges. The heavy metals were released from the oxic sediment gradually during a 24‐h resuspension period. The temporal maximum concentrations of Ni, Cu, Zn, and Cd in the aqueous phases in both experiments frequently exceeded the USEPA water quality criteria or the water quality guidelines of Australia and New Zealand. This suggests that a resuspension event could bring about temporal water quality deterioration in the two sediment environments.     

带凝析气顶挥发性油藏水平井优化设计:以轮南油田JⅢ(6+7)油组为例

针对轮南油田JⅢ(6+7)油组曲实际油藏地质条件,利用相图判别法研究了该油藏的流体类型,并确定了油环的大小.在此基础上提出利用水平井开发此类泊藏,并进行了优化设计研究.研究结果表明:JⅢ(6+7)油组的油环原油地层流体样品为挥发油体系,并且油环的体积远大于凝析气顶.本油组适合水平井开发,水平段长度为350～400 m较...     

Impacts of uncertainty in AVOC emissions on the summer ROx budget and ozone production rate in the three most rapidly-developing economic growth regions of China

High levels of uncertainty in non-methane volatile organic compound （NMVOC） emissions in China could lead to significant variation in the budget of the sum of hydroxyl （OH） and peroxy （HO2,RO2） radicals （ROx =OH ＋ HO2 ＋ RO2） and the ozone production rate [P（O3）],but few studies have investigated this possibility,particularly with three-dimensional air quality models.We added diagnostic variables into the WRF-Chem model to assess the impact of the uncertainty in anthropogenic NMVOC （AVOC） emissions on the ROx budget and P（O3） in the Beijing-Tianjin-Hebei region,Yangtze River Delta,and Pearl River Delta of China.The WRF-Chem simulations were compared with satellite and ground observations,and previous observation-based model studies.Results indicated that 68％ increases （decreases） in AVOC emissions produced 4％-280％ increases （2％-80％ decreases） in the concentrations of OH,HO2,and RO2 in the three regions,and resulted in 35％-48％ enhancements （26％-39％ reductions） in the primary ROx production and ～ 65％ decreases （68％-73％ increases） of the P（O3） in Beijing,Shanghai,and Guangzhou.For the three cities,the two largest contributors to the ROx production rate were the reaction of O1D ＋ H2O and photolysis of HCHO,ALD2,and others; the reaction of OH ＋ NO2 （71％-85％） was the major ROx sink; and the major contributor to P（O3） was the reaction of HO2 ＋ NO （～ 65％）.Our results showed that AVOC emissions in 2006 from Zhang et al.（2009） have been underestimated by ～ 68％ in suburban areas and by ＞ 68％ in urban areas,implying that daily and hourly concentrations of secondary organic aerosols and inorganic aerosols could be substantially underestimated,and cloud condensation nuclei could be underestimated,whereas local and regional radiation was overestimated.     

泰州市大气挥发性有机物化学组分特征、活性及来源解析

挥发性有机物（VOCs）是臭氧和大气颗粒物的重要前体物,本研究利用在线气相色谱-质谱仪（Online-GC-MS）于2018年5—6月对江苏省泰州市大气中98种VOCs进行监测,依据监测结果对泰州市大气VOCs的组成特征、日变化趋势进行分析,对醛酮类VOCs数据进行参数化拟合探究其一次二次贡献,并采用正矩阵因子分解模型（PMF）对VOCs数据进行来源分析,用最大增量反应活性（MIR）计算臭氧生成潜势（OFP）.研究结果表明：泰州市大气VOCs中烷烃占比最高,其次为醛酮;烷烃、烯烃、卤代烃和芳香烃浓度日变化趋势明显,特征相近;参数化方法表明醛类物质主要来自于二次生成,而酮类物质主要来自一次排放;PMF模型结果表明泰州市VOCs的主要贡献源分别为机动车排放、油气溶剂挥发、生物质燃烧、其他工业和天然源;OFP的主要贡献物种为烯烃类,占比34.18%.研究结果表明,控制工业排放和溶剂使用是泰州市大气污染物控制的重点.