Sea-salt particles are major aerosol constituents in the marine boundary layer (MBL) and are chemically modified by acidic substances from anthropogenic, volcanic, and biogenic sources. When these acidic substances react with sea-salt particles, they can be easily scavenged from the MBL. This scavenging process influences the concentration of cloud condensation nuclei in the MBL. In this study, differences in chemical compositions of sea-salt particles collected over the Pacific Ocean and its marginal seas were investigated based on an individual particle analysis. The sources of the acidic substances that modified sea-salt particles were also estimated. Approximately 70% of the analyzed particles were fresh sea-salt particles. However, a sample collected near Guam was dominated by sulfates and was affected by polluted air masses that originated over the Asian continent. The aerosols collected around the Aleutian Islands included a large number of sulfates and modified sea-salt particles. Individual particle composition analyses indicate that these sea-salt particles were modified by methanesulfonic acid produced from marine biota and sulfuric acid from volcanic gas from the Kamchatka Peninsula. The gravitational deposition velocities of sulfates and modified sea-salt particles were calculated based on measured particle sizes. The results suggested that if acidic substances react with sea-salt particles, their lifetime in the atmosphere could be shortened due to dry deposition. Therefore, it is necessary to consider the scavenging effect of sea-salt particles for estimating the climate cooling effect by clouds over the ocean.

中文翻译：

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在太平洋及其边缘海域南北横断面巡航期间收集的海洋气溶胶的单个粒子分析

海盐颗粒是海洋边界层 (MBL) 中的主要气溶胶成分，并被来自人为、火山和生物来源的酸性物质化学改性。当这些酸性物质与海盐颗粒反应时，它们很容易从 MBL 中清除。这种清除过程会影响 MBL 中云凝结核的浓度。在这项研究中，基于单个粒子分析研究了在太平洋及其边缘海域收集的海盐粒子化学成分的差异。还估计了改变海盐颗粒的酸性物质的来源。大约 70% 的分析颗粒是新鲜海盐颗粒。然而，在关岛附近收集的样本主要是硫酸盐，并受到源自亚洲大陆的污染气团的影响。阿留申群岛周围收集的气溶胶包括大量硫酸盐和改性海盐颗粒。单个颗粒成分分析表明，这些海盐颗粒被海洋生物群产生的甲磺酸和来自堪察加半岛的火山气体的硫酸改性。硫酸盐和改性海盐颗粒的重力沉积速度是根据测得的颗粒尺寸计算出来的。结果表明，如果酸性物质与海盐颗粒发生反应，它们在大气中的寿命会因干沉降而缩短。所以，