Particle hygroscopicity and its link to chemical composition in the urban atmosphere of Beijing, China, during summertime
Particle hygroscopicity and its link to chemical composition in the urban atmosphere of Beijing, China, during summertime
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夏季中国北京城市大气中颗粒吸湿性及其与化学成分的联系
DOI：
10.5194/acp-16-1123-2016
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发表时间：
2015-04
期刊：
影响因子：
--
通讯作者：
Hu M.
中科院分区：
文献类型：
--
作者：
Wu Z. J.;Zheng J.;Shang D. J.;Du Z. F.;Wu Y. S.;Zeng L. M.;Wiedensohler A.;Hu M.
抽象的。2014年夏季，在中国北京同时测量了颗粒数尺寸分布、颗粒吸湿特性和尺寸分辨化学组成。在测量期间，50、100、150、200和250 nm颗粒的平均吸湿性参数（κs）分别为0.16 p 0.07、0.19 p 0.06、0.22 p 0.06、0.26 p 0.07和0.28 p 0.10，显示出随粒度增加而增加的趋势。颗粒吸湿性的尺寸依赖性与PM 1中无机质量分数的依赖性相似。亲水模式（吸湿生长因子，HGF > 1.2）在生长因子概率密度分布中更突出，并且其亲水模式的优势随着颗粒尺寸的增加而变得更明显。当PM2.5质量浓度大于50 μg m−3时，随着PM2.5质量浓度的增加，150、250和350 nm颗粒物的亲水模式分数向1增加。这表明，在北京大气中的重度污染期间，老化颗粒物占主导地位。颗粒吸湿增长可以很好地预测使用高时间分辨率的尺寸分辨的化学成分来自气溶胶质谱仪（AMS）的测量使用Zdanovskiii-Stokes-罗宾逊（ZMR）混合规则。有机物的吸湿性参数（κorg）与氧碳比呈正相关。在与强活性光化学相关的新颗粒形成事件期间，新形成颗粒的吸湿生长因子或κ大于不在新颗粒形成（NPF）期间的具有相同尺寸的颗粒。对于预先存在的颗粒（例如，250 nm颗粒），观察到从外部混合物到内部混合物的快速转变。这种转变可以改变预先存在的颗粒的混合物的状态，从而改变诸如光吸收系数和云凝结核活化的性质。
Abstract. Simultaneous measurements of particle number size distribution, particle hygroscopic properties, and size-resolved chemical composition were made during the summer of 2014 in Beijing, China. During the measurement period, the mean hygroscopicity parameters (κs) of 50, 100, 150, 200, and 250 nm particles were respectively 0.16 p 0.07, 0.19 p 0.06, 0.22 p 0.06, 0.26 p 0.07, and 0.28 p 0.10, showing an increasing trend with increasing particle size. Such size dependency of particle hygroscopicity was similar to that of the inorganic mass fraction in PM1. The hydrophilic mode (hygroscopic growth factor, HGF > 1.2) was more prominent in growth factor probability density distributions and its dominance of hydrophilic mode became more pronounced with increasing particle size. When PM2.5 mass concentration was greater than 50 μg m−3, the fractions of the hydrophilic mode for 150, 250, and 350 nm particles increased towards 1 as PM2.5 mass concentration increased. This indicates that aged particles dominated during severe pollution periods in the atmosphere of Beijing. Particle hygroscopic growth can be well predicted using high-time-resolution size-resolved chemical composition derived from aerosol mass spectrometer (AMS) measurements using the Zdanovskii–Stokes–Robinson (ZSR) mixing rule. The organic hygroscopicity parameter (κorg) showed a positive correlation with the oxygen to carbon ratio. During the new particle formation event associated with strongly active photochemistry, the hygroscopic growth factor or κ of newly formed particles is greater than for particles with the same sizes not during new particle formation (NPF) periods. A quick transformation from external mixture to internal mixture for pre-existing particles (for example, 250 nm particles) was observed. Such transformations may modify the state of the mixture of pre-existing particles and thus modify properties such as the light absorption coefficient and cloud condensation nuclei activation.
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影响因子：
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作者：
Zhijun Wu;Min Hu;Shang Liu;B. Wehner;S. Bauer;Andreas Ma ßling;A. Wiedensohler;T. Petäjä;
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影响因子：
6.3
作者：
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通讯作者：
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影响因子：
6.3
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S. Sihto;J. Mikkilä;J. Vanhanen;M. Ehn;L. Liao;K. Lehtipalo;P. Aalto;J. Duplissy;T. Petäjä;V. Kerminen;M. Boy;M. Kulmala
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影响因子：
6.3
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通讯作者：
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