Enhanced organic mass fraction and decreased hygroscopicity of cloud condensation nuclei (CCN) during new particle formation events
Enhanced organic mass fraction and decreased hygroscopicity of cloud condensation nuclei (CCN) during new particle formation events
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DOI：
10.1029/2009gl040930
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发表时间：
2010-02-04
影响因子：
5.2
通讯作者：
Poeschl, U.
中科院分区：
文献类型：
--
作者：
Dusek, U.;Frank, G. P.;Poeschl, U.
在德国中部城市附近的森林中，小于100 nm的颗粒的CCN效率在新颗粒形成期间显著降低。这导致平均活化直径的增加，分别在0.33%和0.74%的过饱和度下从5%增加到8%。同时，在亚100纳米尺寸范围内的有机质量分数从约2/3增加到3/4。这提供了证据表明，二次有机气溶胶（SOA）成分参与了新颗粒生长到更大的尺寸，并且小颗粒的CCN效率降低是由冷凝材料的低吸湿性引起的。所观察到的颗粒吸湿性（kappa）对化学成分的依赖性可以参数化为通过气溶胶质谱法确定的有机和无机质量分数（f（org），f（inorg））的函数：kappa = kappa（org）f（org）+kappa（inorg）f（inorg）。所获得的k（org）值近似为0.1是SOA的特征，并且kappa（inorg）近似为0.7与所观察到的铵离子、硫酸根离子和硝酸根离子的混合一致。引文：Dusek，U.，G. P. Frank，J. Curtius，F. ^J. Schneider，A.库尔滕，D.罗斯，M. O.安德拉，S. Borrmann和U. Poschl（2010年），在新粒子形成事件期间云凝结核（CCN）的有机质量分数增加和吸湿性降低，Geophys。保留信函：37，L03804，doi：10.1029/2009GL040930。
In a forested near-urban location in central Germany, the CCN efficiency of particles smaller than 100 nm decreases significantly during periods of new particle formation. This results in an increase of average activation diameters, ranging from 5 to 8% at supersaturations of 0.33% and 0.74%, respectively. At the same time, the organic mass fraction in the sub-100-nm size range increases from approximately 2/3 to 3/4. This provides evidence that secondary organic aerosol (SOA) components are involved in the growth of new particles to larger sizes, and that the reduced CCN efficiency of small particles is caused by the low hygroscopicity of the condensing material. The observed dependence of particle hygroscopicity (kappa) on chemical composition can be parameterized as a function of organic and inorganic mass fractions (f(org), f(inorg)) determined by aerosol mass spectrometry: kappa = kappa(org) f(org) + kappa(inorg) f(inorg). The obtained value of k(org) approximate to 0.1 is characteristic for SOA, and kappa(inorg) approximate to 0.7 is consistent with the observed mix of ammonium, sulfate and nitrate ions. Citation: Dusek, U., G. P. Frank, J. Curtius, F. Drewnick, J. Schneider, A. Kurten, D. Rose, M. O. Andreae, S. Borrmann, and U. Poschl (2010), Enhanced organic mass fraction and decreased hygroscopicity of cloud condensation nuclei (CCN) during new particle formation events, Geophys. Res. Lett., 37, L03804, doi: 10.1029/2009GL040930.