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| Titel |
Using measurements of the aerosol charging state in determination of the particle growth rate and the proportion of ion-induced nucleation |
| VerfasserIn |
J. Leppä, S. Gagné, L. Laakso, H. E. Manninen, K. E. J. Lehtinen, M. Kulmala  , V.-M. Kerminen |
| 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 ; 13, no. 1 ; Nr. 13, no. 1 (2013-01-15), S.463-486 |
| Datensatznummer |
250017560
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| Publikation (Nr.) |
 copernicus.org/acp-13-463-2013.pdf |
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| Zusammenfassung |
| The fraction of charged nucleation mode particles as a function of particle
diameter depends on the particle growth rate and the proportion of particles
formed via ion-induced nucleation. In this study we have tested the
applicability of recent data analysis methods to determine the growth rate
and the proportion of ion-induced nucleation from the measured charged
fractions. For this purpose we have conducted a series of aerosol dynamic
simulations covering a wide range of atmospheric conditions. The growth rate
and initial fraction of charged particles were estimated from simulated data
using these methods and compared with the values obtained directly from the
simulations. We found that the data analysis methods used in this study
should not be used when the nuclei growth rate is less than ~3 nm h−1,
or when charged particles grow much more rapidly than neutral
ones. Furthermore, we found that the difference in removal rates of neutral
and charged particles should be taken into account when estimating the
proportion of ion-induced nucleation. Neglecting the higher removal rate of
charged particles compared with that of neutral ones could result in an
underestimation of the proportion of ion-induced nucleation by up to a
factor of 2. This underestimation is further increased if charged particles
grow more rapidly than neutral ones. We also provided a simple way of
assessing whether these methods are suitable for analyzing data measured
under specific conditions. The assessment procedure was illustrated using a
few examples of actual measurement sites with a more detailed examination of
the typical conditions observed at the SMEAR II station in Hyytiälä,
Finland. |
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