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| Titel |
Impacts of new particle formation on aerosol cloud condensation nuclei (CCN) activity in Shanghai: case study |
| VerfasserIn |
C. Leng, Q. Zhang, J. Tao, H. Zhang, D. Zhang, C. Xu, X. Li, L. Kong, T. Cheng, R. Zhang, X. Yang, J. Chen, L. Qiao, S. Lou, H. Wang, C. Chen |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 14, no. 20 ; Nr. 14, no. 20 (2014-10-29), S.11353-11365 |
| Datensatznummer |
250119125
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| Publikation (Nr.) |
 copernicus.org/acp-14-11353-2014.pdf |
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| Zusammenfassung |
| New particle formation (NPF) events and their impacts on cloud condensation
nuclei (CCN) were investigated using continuous measurements collected in
urban Shanghai from 1 to 30 April 2012. During the campaign, NPF occurred in
8 out of the 30 days and enhanced CCN number concentration (NCCN) by a
factor of 1.2–1.8, depending on supersaturation (SS). The NPF event on 3
April 2012 was chosen as an example to investigate the NPF influence on CCN
activity. In this NPF event, secondary aerosols were produced continuously
and increased PM2.5 mass concentration at a rate of 4.33 μg cm−3 h−1, and the growth rate (GR) and formation rate (FR) were on
average 5 nm h−1 and 0.36 cm−3 s−1, respectively. The newly
formed particles grew quickly from nucleation mode (10–20 nm) into CCN size
range. NCCN increased rapidly at SS of 0.4–1.0% but weakly at SS of
0.2%. Correspondingly, aerosol CCN activities (fractions of activated
aerosol particles in total aerosols, NCCN/NCN) were significantly
enhanced from 0.24–0.60 to 0.30–0.91 at SS of 0.2–1.0% due to the NPF. On
the basis of the κ-Köhler theory, aerosol size distributions and
chemical composition measured simultaneously were used to predict NCCN.
There was a good agreement between the predicted and measured NCCN (R2=0.96, Npredicted/Nmeasured=1.04). This study
reveals that NPF exerts large impacts on aerosol particle abundance and size
spectra; thus, it significantly promotes NCCN and aerosol CCN activity in
this urban environment. The GR of NPF is the key factor controlling the
newly formed particles to become CCN at all SS levels, whereas the FR is an
effective factor only under high SS (e.g., 1.0%) conditions. |
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