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| Titel |
Strong atmospheric new particle formation in winter in urban Shanghai, China |
| VerfasserIn |
S. Xiao, M. Y. Wang, L. Yao, M. Kulmala  , B. Zhou, X. Yang, J. M. Chen, D. F. Wang, Q. Y. Fu, D. R. Worsnop, L. Wang |
| 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 ; 15, no. 4 ; Nr. 15, no. 4 (2015-02-19), S.1769-1781 |
| Datensatznummer |
250119443
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| Publikation (Nr.) |
 copernicus.org/acp-15-1769-2015.pdf |
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| Zusammenfassung |
| Particle size distributions in the range of 1.34–615 nm were
recorded from 25 November 2013 to 25 January 2014 in urban
Shanghai, using a combination of one nano condensation nucleus counter
system, one nano scanning mobility particle sizer (SMPS), and one
long-SMPS. Measurements of sulfur dioxide by an SO2 analyzer with
pulsed UV fluorescence technique allowed calculation of sulfuric acid proxy.
In addition, concentrations of ammonia were recorded with a differential
optical absorption spectroscopy. During this 62-day campaign, 13 new particle formation (NPF)
events were identified with strong bursts of sub-3 nm particles and
subsequent fast growth of newly formed particles. The observed nucleation
rate (J1.34), formation rate of 3 nm particles (J3), and
condensation sink were 112.4–271.0 cm−3 s−1, 2.3–19.2 cm−3 s−1, and 0.030–0.10 s−1, respectively. Subsequent
cluster/nanoparticle growth (GR) showed a clear size dependence, with average
values of GR1.35~1.39, GR1.39~1.46, GR1.46~1.70,
GR1.70~2.39, GR2.39~7, and GR7~20 being
1.6±1.0, 1.4±2.2, 7.2±7.1, 9.0±11.4, 10.9±9.8, and 11.4±9.7 nm h−1, respectively. Correlation between
nucleation rate (J1.34) and sulfuric acid proxy indicates that
nucleation rate J1.34 was proportional to a 0.65±0.28
power of sulfuric acid proxy, indicating that the nucleation of particles
can be explained by the activation theory. Correlation between nucleation
rate (J1.34) and gas-phase ammonia suggests that ammonia was
associated with NPF events. The calculated sulfuric acid proxy was
sufficient to explain the subsequent growth of 1.34–3 nm particles, but its
contribution became smaller as the particle size grew. Qualitatively, NPF
events in urban Shanghai likely occur on days with low levels of aerosol
surface area, meaning the sulfuric acid proxy is only a valid predictor when
aerosol surface area is low. |
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