Aggarwal Shankar Gopala, Mochida Michihiro, Kitamori Yasuyuki, Kawamura Kimitaka
Institute of Low Temperature Science, Hokkaido University, Kita 19, Nishi 8, Kita-ku, Sapporo 060-0819, Japan.
Environ Sci Technol. 2007 Oct 15;41(20):6920-5. doi: 10.1021/es063092m.
To assess the link between hygroscopicity of atmospheric particles and the chemical composition, we performed a chemical closure study on the hygroscopicity of organic-inorganic mixed particles nebulized from water extracts of ambient aerosols collected in Sapporo, Japan during summer 2005. The hygroscopicity of 100 nm particles was measured using a hygroscopicity tandem differential mobility analyzer (HTDMA) at 5-95% relative humidity. The chemical analyses of the extracts showed that inorganic salts accounted for 32-84% of the water-soluble fraction and that the remaining was water-soluble organic matter (WSOM). The liquid water content (LWC) of particles was primarily governed by the relative abundance of inorganic salts in particles. The chemical closure with a thermodynamic model did not indicate a significant perturbation of LWC by WSOM at 85% RH with the consideration of the uncertainties estimated. However, a positive perturbation by WSOM was suggested at 50% RH. Individual oxygenated compounds identified using gas chromatography were not abundant enough to substantially increase the LWC at 85% RH.
为了评估大气颗粒物的吸湿性与化学成分之间的联系，我们对2005年夏季在日本札幌采集的环境气溶胶水提取物雾化产生的有机-无机混合颗粒物的吸湿性进行了化学闭合研究。使用吸湿性串联差分迁移率分析仪（HTDMA）在相对湿度为5-95%的条件下测量了100纳米颗粒物的吸湿性。提取物的化学分析表明，无机盐占水溶性部分的32-84%，其余为水溶性有机物（WSOM）。颗粒物的液态水含量（LWC）主要受颗粒物中无机盐相对含量的控制。考虑到估计的不确定性，用热力学模型进行的化学闭合并未表明在85%相对湿度下WSOM对LWC有显著扰动。然而，在50%相对湿度下，WSOM显示出正扰动。使用气相色谱法鉴定的单个氧化化合物数量不足，不足以在85%相对湿度下大幅增加LWC。
