Rapid aerosol particle growth and increase of cloud condensation nucleus activity by secondary aerosol formation and condensation: A case study for regional air pollution in northeastern China
Rapid aerosol particle growth and increase of cloud condensation nucleus activity by secondary aerosol formation and condensation: A case study for regional air pollution in northeastern China
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DOI：
10.1029/2008jd010884
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发表时间：
2009-01
影响因子：
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通讯作者：
A. Wiedensohler;Yafang Cheng;A. Nowak;B. Wehner;P. Achtert;M. Berghof;W. Birmili;Zhijun Wu;
中科院分区：
文献类型：
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作者：
A. Wiedensohler;Yafang Cheng;A. Nowak;B. Wehner;P. Achtert;M. Berghof;W. Birmili;Zhijun Wu;
[1]本研究是2006年北京及周边地区空气质量研究国际实地测量活动（CAREBeijing-2006）的一部分。本文研究了北京南部一个高污染气团中一次新的粒子形成事件及其对云凝结核（CCN）丰度和性质的影响。在1个月的观察，粒子成核，然后在区域尺度上显着的粒子生长经常观察（~30%），我们选择2006年8月23日作为一个代表性的案例研究。二次气溶胶质量不断产生，硫酸盐，铵和有机物作为主要成分。气溶胶质量增长率平均为19 μg·m-3·h-1。在1个月的密集测量期间多次观察到这种生长速率。成核模式非常迅速地生长到CCN的尺寸范围内，并且CCN的尺寸分布由生长成核模式（高达总CCN数浓度的80%）主导，而不是通常由积累模式主导。在水汽过饱和度为0.07- 0.86%时，CCN数浓度在成核后6-14 h达到最大值4000- 19000 cm-3。在颗粒形成和生长过程中，对于直径为40-90 nm的颗粒，有效吸湿性参数κ从约0.1-0.3增加到0.35-0.5，但对于直径为~190 nm的颗粒，其几乎保持恒定在~0.45。这一结果与气溶胶化学成分数据一致，表明硫酸盐明显增加。
[1] This study was part of the international field measurement Campaigns of Air Quality Research in Beijing and Surrounding Region 2006 (CAREBeijing-2006). We investigated a new particle formation event in a highly polluted air mass at a regional site south of the megacity Beijing and its impact on the abundance and properties of cloud condensation nuclei (CCN). During the 1-month observation, particle nucleation followed by significant particle growth on a regional scale was observed frequently (~30%), and we chose 23 August 2006 as a representative case study. Secondary aerosol mass was produced continuously, with sulfate, ammonium, and organics as major components. The aerosol mass growth rate was on average 19 μg m -3 h -1 during the late hours of the day. This growth rate was observed several times during the 1-month intensive measurements. The nucleation mode grew very quickly into the size range of CCN, and the CCN size distribution was dominated by the growing nucleation mode (up to 80% of the total CCN number concentration) and not as usual by the accumulation mode. At water vapor supersaturations of 0.07-0.86%, the CCN number concentrations reached maximum values of 4000-19,000 cm -3 only 6-14 h after the nucleation event. During particle formation and growth, the effective hygroscopicity parameter κ increased from about 0.1-0.3 to 0.35-0.5 for particles with diameters of 40-90 nm, but it remained nearly constant at ~0.45 for particles with diameters of ~190 nm. This result is consistent with aerosol chemical composition data, showing a pronounced increase of sulfate.