Studies on chemistry and cycles of halogens in the troposphere

对流层中卤素的化学和循环研究

• 批准号: 10144101
• 负责人: KAWAMURA Kimitaka
• 金额: $ 81.02万
• 依托单位: HOKKAIDO UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research on Priority Areas (A)
• 财政年份: 1998
• 资助国家: 日本
• 起止时间: 1998 至 2000
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10144101/
• 关键词: Halogen; Chlorine; Bromine; Aerosols; Photochemical reaction; Marine atmosphere; Seawater; Troposphere; 対流圏

In this program, we conducted several projects. They include (l) measurements of inorganic halogens and their atmospheric behaviors, (2) development of halogen measurement and its application to the atmosphere, (3) atmospheric behaviors of halogenated volatile hydrocarbons, (4) halogenated organics in aerosols and analysis of organic aerosols, (5) carbon isotopic analysis of non-methane hydrocarbons, (6) dynamics and interaction of halogens in air/water interface, and (7) formation mechanism and cycles of biogenic halocarbons.We made a new analytical system to measure hologen gases by using scrubber technique. By using this method, a formation of halogen gases from the sea salt particles was observed. We also observed a decrease in the concentration of Cl^2 and an increase of HCl gas in daytime in the marine atmosphere. A chemical ionization mass spectrometer that was designed for the measurement of Br^2 and Cl^2, has been made in this study. Using this instrument for laboratory experiment, we observed the formation of Br^2 gas on the surface of sea salt particles as a result of Cl uptake. We also confirmed the release of halogen gases from the sea salts by the reaction with ozone. Seawater and air samples collected from the Pacific Ocean were analyzed for holocarbons using a purge and trap GC/mass spectrometry. We found a seasonal change of halogen compounds with maxima in August/September in the western North Pacific. In the marine aerosols, we identified, for the first time, halogenated organic acids and aldehydes, including bromosuccinic and chlorosuccinic acids. The former acid showed higher concentrations in the western North Pacific near Asia continent, whereas the latter increased in the central Pacific. Based on the observations over the Pacific, we proposed a photochemical formation model for the newly rescovered halogenated organic compounds and an evolution model of organic aerosols.

在这个计划中，我们进行了几个项目。它们包括（l）无机卤素的测量及其大气行为，（2）卤素测量的发展及其在大气中的应用，（3）卤代挥发性烃的大气行为，（4）气溶胶中的卤代有机物和有机气溶胶的分析，（5）非甲烷碳氢化合物的碳同位素分析，（6）空气/水界面中卤素的动力学和相互作用，以及（7）生物卤代碳的形成机制和循环。我们做了新的分析使用洗涤器技术测量卤素气体的系统。通过使用这种方法，观察到海盐颗粒形成卤素气体。我们还观察到白天海洋大气中 Cl^2 浓度下降，HCl 气体增加。本研究制作了一种用于测量Br^2和Cl^2的化学电离质谱仪。使用该仪器进行实验室实验，我们观察到由于吸收Cl而在海盐颗粒表面形成Br^2气体。我们还证实海盐与臭氧反应会释放卤素气体。使用吹扫捕集气相色谱/质谱分析从太平洋收集的海水和空气样本中的全碳。我们发现北太平洋西部卤素化合物的季节变化在8月/9月达到最大值。在海洋气溶胶中，我们首次鉴定出卤代有机酸和醛，包括溴代琥珀酸和氯代琥珀酸。前者在亚洲大陆附近的北太平洋西部表现出较高浓度，而后者在太平洋中部则有所增加。基于对太平洋的观测，我们提出了新发现的卤代有机化合物的光化学形成模型和有机气溶胶的演化模型。