Park S H, Song C B, Kim M C, Kwon S B, Lee K W
University of British Columbia, Mechanical Engineering, 2324 Main Mall, Vancouver, British Columbia, Canada.
Environ Monit Assess. 2004 Apr-May;93(1-3):157-83. doi: 10.1023/b:emas.0000016805.04194.56.
Soil dust particles transported from loess regions of the Asian continent, called Asian dust, highly influences the air quality of north-eastern Asia and the northern Pacific Ocean. In order to investigate the effects of these dust storms on the chemical composition of atmospheric aerosol particles with different size, measurements of size distributions of total aerosol and major ion species were carried out on Jeju Island, Korea during April 2001. Juju Island was chosen for the study because the levels of emissions of anthropogenic air pollutants are very low. A 5-stage cascade impactor was used to sample size-fractionated aerosol particles. Samples were analyzed for major water-soluble ions using Dionex DX-120 ion chromatograph. The average mass concentration of total aerosol was found to be 24.4 and 108.3 microg m(-3) for non-Asian dust and Asian dust periods, respectively. The total aerosol size distribution, measured during the non-Asian dust period, was bimodal, whereas the coarse particles dominated the size distribution of total aerosol during the Asian dust period. It was found that SO4(2-), NH4+ and K+ were mainly distributed in fine particles, while Cl-, NO3-, Na+, Mg2+ and Ca2+ were in coarse particles. Although SO4(2-) was mainly distributed in fine particles, during the Asian dust period, the concentrations in coarse particles were significantly increased. This indicates heterogeneous oxidation of SO2 on wet surfaces of basic soil dust particles. The NH4+ was found to exist as (NH4)2SO4 in fine particles, with a molar ratio of NH4+ to SO4(2-) of 2.37 and 1.52 for non-Asian dust and Asian dust periods, respectively. Taking into account the proximity of the sampling site to the sea, and the observed chloride depletion, coarse mode nitrate, during the non-Asian dust period, is assumed to originate from the reaction of nitric acid with sodium chloride on the surfaces of sea-salt particles although the chloride depletion was not shown to be large enough to prove this assumption. During the Asian dust period, however, chloride depletion was much smaller, indicating coarse nitrate particles were mainly produced by the reaction of nitric acid with surfaces of basic soil particles. Most chloride and sodium components were shown to originate from sea-salt particles. Asian dust aerosols, arriving at Jeju Island, contained considerable amounts of sea-salt particles as they passed over the Yellow Sea. Ca2+ was shown to be the most abundant species in Asian dust particles.
从亚洲大陆黄土地区输送来的土壤尘埃颗粒，即所谓的亚洲沙尘，对东北亚和北太平洋的空气质量有很大影响。为了研究这些沙尘暴对不同粒径大气气溶胶颗粒化学成分的影响，于2001年4月在韩国济州岛对总气溶胶和主要离子种类的粒径分布进行了测量。选择济州岛进行这项研究是因为人为空气污染物的排放水平很低。使用五级串联撞击器对粒径分级的气溶胶颗粒进行采样。使用戴安DX - 120离子色谱仪对样品中的主要水溶性离子进行分析。发现非亚洲沙尘期和亚洲沙尘期总气溶胶的平均质量浓度分别为24.4和108.3微克/立方米。在非亚洲沙尘期测量的总气溶胶粒径分布是双峰的，而在亚洲沙尘期粗颗粒主导了总气溶胶的粒径分布。发现SO4(2 - )、NH4 + 和K + 主要分布在细颗粒中，而Cl - 、NO3 - 、Na + 、Mg2 + 和Ca2 + 分布在粗颗粒中。尽管SO4(2 - )主要分布在细颗粒中，但在亚洲沙尘期，粗颗粒中的浓度显著增加。这表明SO2在碱性土壤尘埃颗粒的潮湿表面发生了非均相氧化。发现NH4 + 在细颗粒中以(NH4)2SO4的形式存在，非亚洲沙尘期和亚洲沙尘期NH4 + 与SO4(2 - )的摩尔比分别为2.37和1.52。考虑到采样点靠近大海以及观察到的氯亏损现象，在非亚洲沙尘期，粗模态硝酸盐被认为起源于硝酸与海盐颗粒表面氯化钠的反应，尽管氯亏损程度还不足以证明这一假设。然而，在亚洲沙尘期，氯亏损要小得多，这表明粗硝酸盐颗粒主要是由硝酸与碱性土壤颗粒表面反应产生的。大多数氯和钠成分被证明起源于海盐颗粒。到达济州岛的亚洲沙尘气溶胶在经过黄海时含有大量海盐颗粒。Ca2 + 被证明是亚洲沙尘颗粒中含量最丰富的成分。
