北京地区大气中卤代烃含量的初步测定

研究了用电子捕获检测器测定大气中多种卤代烃化合物的气相色谱方法.选择的色谱分离柱有气液色谱柱25％DC-200 Chromosorb WAW DCMS(60—80目)和气固色谱柱carbopack CHT(80—100目).在等温条件下,以直接采样和直接进样方式分别测定了大气中多种卤代烃成份,并且比较了两根色谱柱的分析结果间的差异.在北京地区初步测定了主要的卤代烃如CFC-11,CFC-12,CHCl_3,CH_3CCl_3,CCl_4,CHCl=CCl_2和CCl_2=CCl_2的含量,其各自相应的浓度分别是127±24,275±12,49±32,80±27,60±18,8±2和30±17ppt(V/V).     

西太平洋添加营养盐培养实验中挥发性卤代烃含量动态变化

于2018年10月9日~11月1日采集西太平洋表层海水，通过营养盐添加船基培养实验，研究了不同营养盐条件下浮游植物的生长及其释放挥发性卤代烃（VHCs）含量的动态变化规律.结果表明，与对照组相比，氮磷营养盐的添加对叶绿素a（Chl-a）的含量和三氯乙烯（C₂HCl₃），四氯乙烯（C₂Cl₄），一氯二溴甲烷（CHBr₂Cl），三溴甲烷（CHBr₃）的释放量表现出显著促进作用，但促进程度与添加氮磷营养盐的浓度及比值密切相关.高浓度氮更有利于浮游植物的生长及C₂HCl₃和C₂Cl₄的释放.N/P比符合Redfield比值更有利于CHBr₂Cl和CHBr₃的释放.相比NO₃^--N，NH₄⁺-N的添加更有利于4种VHCs释放.     

泰山大气卤代烃的长期变化趋势与来源

卤代烃是大气环境与气候变化研究的热点问题.基于2003～2018年在泰山山顶（36.25°N, 117.10°E,海拔1 534 m）的6期强化观测数据,结合气流轨迹模型与受体源解析模型,分析了华北平原区域背景大气中卤代烃的长期变化趋势和主要来源.结果表明,《蒙特利尔议定书》已淘汰物种（CFC-12、 CFC-11、 CFC-113、 H-1211、 CCl₄和CH₃CCl₃）体积分数显著下降,受管控物种（HCFC-22、 HCFC-141b、 HCFC-142b和HFC-134a）及未列入管控的物种（CH₂Cl₂、 C₂Cl₄、 CH₃Cl、 CHCl₃）体积分数则呈上升趋势且体积分数中位值显著高于北半球中纬度大气背景中位值;泰山卤代烃的体积分数主要受4种不同来向气团输送的影响,其中来自华北地区气团占比最高（41%）;主要来源包括生物质燃烧（38.1%）、制冷剂（26.2%）、工业及家用溶...     

聚乙烯微塑料对海洋微藻生长和卤代烃释放的影响

挥发性卤代烃（VHCs）是一类重要的痕量温室气体和臭氧破坏物质,在全球气候变化中发挥重要作用.微藻释放VHCs受海洋环境因素的影响.微塑料作为海洋中一种重要新型污染物其对海洋微藻释放VHCs的影响研究比较少见.基于小新月菱形藻（Nitzschia closterium f.minutissima）和东海原甲藻（Prorocentrum donghaiense）的室内单种培养实验,通过测定其藻细胞密度、最大光量子效率（F_v/F_m）、活性氧（ROS）和VHCs浓度,研究聚乙烯（PE）微塑料长期暴露对小新月菱形藻和东海原甲藻生长和VHCs释放的影响.结果表明,PE微塑料胁迫对小新月菱形藻生长主要表现抑制作用,而对东海原甲藻生长表现出促进作用.50 μm的PE微塑料的添加对小新月菱形藻和东海原甲藻的光合作用起到遮蔽作用,导致二者的F_v/F_m受到抑制,且其对东海原甲藻的抑制作用更显著.与对照组相比,PE微塑料胁迫刺激藻细胞的ROS产生量增加,引起小新月菱形藻和东海原甲藻的氧化应激反应,从而促进两种微藻3种溴代烃的释放.     

Marine macroalgae in polar regions as natural sources for volatile organohalogens

Marine macroalgae species from the polar regions were investigated for their importance as natural sources of volatile halogenated compounds released into the biosphere. Several different halogenated C1 to C4 hydrocarbons were identified and their release rates determined. The compounds contained mainly bromine and iodine, and form was the dominant compound released. Although an annual atmospheric input of approximately 10(8)-10(10) g bromine and 10(7)-10(8) g iodine was calculated from the release rates, marine macroalgae are apparently not the major source on a global scale, as the release is up to four orders of magnitude lower than a presumed annual flow from the oceans. Despite this, macroalgae may be more important on a local scale due to their occurrence at a high biomass in the coastal regions. The present paper gives an overview about studies done on the release of volatile halocarbons by macroalgae from polar regions. Furthermore, the function of these compounds in the macroalgal metabolism is discussed.     

东海海水和大气中挥发性卤代烃的分布

运用吹扫-捕集气相色谱法于2016年6月对东海海水和大气中5种短寿命挥发性卤代烃的浓度含量、分布来源特征及海-气通量进行了研究.结果表明,表层海水中CH₃I、CH₂Br₂、CHBrCl₂、CHBr₂Cl和CHBr₃浓度平均值及范围分别为8.93（0.39~23.49） pmol/L、15.02（4.77~32.75） pmol/L、0.97（0.30~2.16） pmol/L、9.35（6.8~18.46） pmol/L和12.24（2.60~50.04） pmol/L.受陆源输入、水团和生物活动释放的影响,表层海水中CH₃I、CH₂Br₂和CHBrCl₂的浓度分布呈现近岸高远海低的趋势,CHBr₂Cl和CHBr₃浓度呈现点状分布.相关性分析发现CHBr₃和Chl-a存在显著相关性,推断浮游植物生物量可能影响CHBr₃的浓度分布.大气中CH₃I、CH₂Br₂、CHBrCl₂、CHBr₂Cl和CHBr₃浓度平均值及范围分别为3.52×10^-12（1.72×10^-12~10.00×10^-12）、3.82×10^-12（0.20×10^-12~34.95×10^-12）、1.40×10^-12（0.46×10^-12~6.18×10^-12）、1.55×10^-12（0.16×10^-12~4.66×10^-12）和6.63×10^-12（2.20×10^-12~11.61×10^-12）.受陆源气团输送、生物生产和气象条件的共同影响,春季大气中5种短寿命挥发性卤代烃浓度分布较为复杂.海-气通量的估算结果表明春季东海是大气中CH₃I、CH₂Br₂、CHBrCl₂、CHBr₂Cl和CHBr₃的源.     

Atmospheric measurements of the halogenated hydrocarbons involved in global change phenomena

Chlorofluorocarbons and their replacement compounds are anthropogenic compounds of great environmental concern. For this reason monitoring their atmospheric mixing ratios on a worldwide scale is recommended. An analytical methodology for the simultaneous determination of selected chlorofluorocarbons and their replacement compounds has recently been developed. This methodology was applied in the analysis of actual air samples collected in remote and semi-remote areas located in the Northern and Southern Hemispheres. The concentration levels measured in the air samples collected in the two hemispheres are reported.     

大气中CH_4和N_2O浓度变化对氟氯碳化合物损耗O_3及ODP的影响

用计数物种法研究了ＣＨ_４、Ｎ_２Ｏ大气浓度的增长对氟氯碳化合物损耗Ｏ_３过程的影响。在０～２０ｋｍ大气范围内，ＮＯ_Ｘ增加幅度最大，引起这一区域的Ｏ_３有较大增长，ＨＯ_Ｘ浓度有所降低使ＨＣＦＣ_Ｓ在该区域的分解速率大为降低；在平流层中上层，由于ＣＨ_４、ＨＯ_Ｘ和ＮＯ_Ｘ的增加，使得对Ｃｌ原子多种储库分子有较大幅度的增加，氟氯碳化合物对臭氧的消耗能力因此有所减少。微量成分对臭氧消耗潜势（ＯＤＰ）值的影响幅度不大、方向也不确定。     

用参数方程的方法计算氟氯碳化合物的臭氧消耗潜势

在研究同类氟氯碳化合物臭氧消化潜势之间的差异，探讨ＯＤＰ与有关参数必然的内在联系的基础上，建立起两类求算ＨＣＦＣｓ，ＣＦＣｓ的ＯＤＰ的参数方程。一类是以大气寿命τ为参变量的计算ＯＤＰ的参数方程，与之相应，发展了一种仅含氟氯碳化合物分解反应的得     

The origin of stable halogenated compounds in volcanic gases

BACKGROUND: Halogenated compounds in the atmosphere are of great environmental concern due to their demonstrated negative effect on atmospheric chemistry and climate. Detailed knowledge of the emission budgets of halogenated compounds has to be gained to understand better their specific impact on ozone chemistry and the climate. Such data are also highly relevant to guide policy decisions in connexion with international agreements about protection of the ozone layer. In selected cases, the relevance of specific emission sources for certain compounds were unclear. In this study we present new and comprehensive evidence regarding the existence and relevance of a volcanic contribution of chlorofluorocarbons (CFCs), hydrofluorocarbons (HFCs), hydrochlorofluorocarbons (HCFCs), halons (bromine containing halo(hydro)carbons), and fully fluorinated compounds (e.g. CF4 and SF6) to the atmospheric budget. METHODS: In order to obtain new evidence of a volcanic origin of these compounds, we collected repeatedly, during four field campaigns covering a period of two years, gases from fumaroles discharging over a wide range of temperatures at the Nicaraguan subduction zone volcanoes Momotombo, Cerro Negro and Mombacho, and analysed them with very sensitive GC/MS systems. RESULTS AND DISCUSSION: In most fumarolic samples certain CFCs, HFCs, HCFCs, halons, and the fully fluorinated compounds CF4 and SF6 were present above detection limits. However, these compounds occur in the fumarole gases in relative proportions characteristic for ambient air. CONCLUSION: This atmospheric fingerprint can be explained by variable amounts of air entering the porous volcanic edifices and successively being incorporated into the fumarolic gas discharges. Recommendation and Outlook. Our results suggest that the investigated volcanoes do not constitute a significant natural source for CFCs, HFCs, HCFCs, halons, CF4, SF6 and NF3.