Journal cover Journal topic
Atmospheric Chemistry and Physics An interactive open-access journal of the European Geosciences Union
Atmos. Chem. Phys., 16, 8593-8607, 2016
https://doi.org/10.5194/acp-16-8593-2016
© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
15 Jul 2016
Variation of CCN activity during new particle formation events in the North China Plain
Nan Ma1,2,4, Chunsheng Zhao2, Jiangchuan Tao2, Zhijun Wu3, Simonas Kecorius1, Zhibin Wang1,4, Johannes Größ1, Hongjian Liu2, Yuxuan Bian2, Ye Kuang2, Monique Teich1, Gerald Spindler1, Konrad Müller1, Dominik van Pinxteren1, Hartmut Herrmann1, Min Hu3, and Alfred Wiedensohler1 1Leibniz Institute for Tropospheric Research, Leipzig 04318, Germany
2Department of Atmospheric and Oceanic Sciences, School of Physics, Peking University, Beijing 100871, China
3College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
4Multiphase Chemistry Department, Max Planck Institute for Chemistry, Mainz 55128, Germany
Abstract. The aim of this investigation was to obtain a better understanding of the variability of the cloud condensation nuclei (CCN) activity during new particle formation (NPF) events in an anthropogenically polluted atmosphere of the North China Plain (NCP). We investigated the size-resolved activation ratio as well as particle number size distribution, hygroscopicity, and volatility during a 4-week intensive field experiment in summertime at a regional atmospheric observatory in Xianghe. Interestingly, based on a case study, two types of NPF events were found, in which the newly formed particles exhibited either a higher or a lower hygroscopicity. Therefore, the CCN activity of newly formed particles in different NPF events was largely different, indicating that a simple parameterization of particle CCN activity during NPF events over the NCP might lead to poor estimates of CCN number concentration (NCCN). For a more accurate estimation of the potential NCCN during NPF events, the variation of CCN activity has to be taken into account. Considering that a fixed activation ratio curve or critical diameter are usually used to calculate NCCN, the influence of the variation of particle CCN activity on the calculation of NCCN during NPF events was evaluated based on the two parameterizations. It was found that NCCN might be underestimated by up to 30 % if a single activation ratio curve (representative of the region and season) were to be used in the calculation; and might be underestimated by up to 50 % if a fixed critical diameter (representative of the region and season) were used. Therefore, we suggest not using a fixed critical diameter in the prediction of NCCN in NPF. If real-time CCN activity data are not available, using a proper fixed activation ratio curve can be an alternative but compromised choice.

Citation: Ma, N., Zhao, C., Tao, J., Wu, Z., Kecorius, S., Wang, Z., Größ, J., Liu, H., Bian, Y., Kuang, Y., Teich, M., Spindler, G., Müller, K., van Pinxteren, D., Herrmann, H., Hu, M., and Wiedensohler, A.: Variation of CCN activity during new particle formation events in the North China Plain, Atmos. Chem. Phys., 16, 8593-8607, https://doi.org/10.5194/acp-16-8593-2016, 2016.
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Short summary
New particle formation (NPF) is one of main sources of cloud condensation nuclei (CCN) in the atmosphere. Based on in situ measurements, we found that CCN activity of newly formed particles largely differs in different NPF events. It is therefore difficult to find a simple parameterization of CCN activity for NPF events. Using a fixed size-resolved activation ratio curve or critical diameter is very likely to result in large biases up to 50 % in the calculated NCCN during NPF events.
New particle formation (NPF) is one of main sources of cloud condensation nuclei (CCN) in the...
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