Measurements of properties of marine aerosols on research vessel

由于室内和室外样品的湿度不同，在实验室测量大气气溶胶的粒度分布是很困难的。滤膜上的样品伪影也是化学分析中的一个严重问题。为了解决湿度对粒度测量的影响，使用了两个系统来测量干燥和潮湿条件下的粒度分布(Miura)。用水透析法(Niimura和Miura)研究了单个颗粒的混合结构。为了解决人工干扰的问题，用Uematsu实时分析仪连续测量硫酸盐和硝酸盐浓度。作为大陆大气质量的示踪剂，连续测量了小岛大气中的氡浓度。主要结果如下：1.用TDMA研究了海洋亚微米粒子的湿度特性。海洋气溶胶的生长分数几乎为100%，生长因子略小于氯化钠。但这些气溶胶的潮解湿度与氯化钠的潮解湿度一致。气溶胶的生长因子和生长分数受大陆气团的影响而减小。这些特性取决于气溶胶来源和天气条件。用透射电子显微镜、能谱和水渗析相结合的方法研究了单个颗粒的混合特性。对收集在北太平洋上空的颗粒物进行元素分析表明，大部分颗粒物中含有水溶性物质。混合颗粒在所有颗粒中的数量比例从40%到80%不等。对于收集在东中国海面上的粒子，元素分析表明，KOSA事件的一些混合粒子的比例是非KOSA事件的两到三倍。这些结果表明，当气团从大陆输送过来时，海洋大气受到烟尘或混合了水溶性物质的KOSA颗粒的影响。

It is difficult to measure the size distribution of atmospheric aerosol in laboratory because humidity of sample is different between outdoor and indoor. The artifact of sample on the filter is also a sever problem in chemical analysis.To solve the problem of the humidity effects on size measuring two systems were using to measure size distribution in dry and wet conditions (Miura). An intermixture structure of individual particles was examined by a water dialysis (Niimura and Miura). To solve the problem of the artifact sulfate and nitrate concentration were measured with real time analyzer continuously (Uematsu). Radon concentration was measured continuously as a tracer of continental air mass (Kojima).Main results are as follows :1. Humidity properties of marine submicron particles were investigated with the TDMA. Growth fraction of marine aerosol was almost 100 % and growth factor was a little smaller than that of NaCl. But the deliquescence humidity of these aerosols agreed with that of NaCl. Growth factor and growth fraction of aerosols decrease as they are affected by continental air mass. These properties are dependent on aerosol sources and weather condition.2. The mixing properties of individual particles were studied by using a combination of TEM, EDX and a water dialysis. For the particles collected over the North Pacific, the elemental analysis showed that most of particles contained water-soluble material. A number fraction of "Mixed" particles in all particles ranged from 40 to 80%. For particles collected over the East China Sea, the elemental analysis showed that a number fraction of "Mixed" particles of Kosa event was twice or three times that of non-Kosa event. These results imply that marine atmosphere is influence by soot or Kosa particles mixed with water-soluble materials, when the air mass is transported from the Continent.