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| Titel |
An improved criterion for new particle formation in diverse atmospheric environments |
| VerfasserIn |
C. Kuang, I. Riipinen, S.-L. Sihto, M. Kulmala  , A. V. McCormick, P. H. McMurry |
| 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 ; 10, no. 17 ; Nr. 10, no. 17 (2010-09-08), S.8469-8480 |
| Datensatznummer |
250008760
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| Publikation (Nr.) |
 copernicus.org/acp-10-8469-2010.pdf |
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| Zusammenfassung |
| A dimensionless theory for new particle formation (NPF) was developed, using
an aerosol population balance model incorporating recent developments in
nucleation rates and measured particle growth rates. Based on this
theoretical analysis, it was shown that a dimensionless parameter LΓ,
characterizing the ratio of the particle scavenging loss rate to the
particle growth rate, exclusively determined whether or not NPF would occur
on a particular day. This parameter determines the probability that a
nucleated particle will grow to a detectable size before being lost by
coagulation with the pre-existing aerosol. Cluster-cluster coagulation was
shown to contribute negligibly to this survival probability under conditions
pertinent to the atmosphere. Data acquired during intensive measurement
campaigns in Tecamac (MILAGRO), Atlanta (ANARChE), Boulder, and
Hyytiälä (QUEST II, QUEST IV, and EUCAARI) were used to test the
validity of LΓ as an NPF criterion. Measurements included aerosol
size distributions down to 3 nm and gas-phase sulfuric acid concentrations.
The model was applied to seventy-seven NPF events and nineteen non-events
(characterized by growth of pre-existing aerosol without NPF) measured in
diverse environments with broad ranges in sulfuric acid concentrations,
ultrafine number concentrations, aerosol surface areas, and particle growth
rates (nearly two orders of magnitude). Across this diverse data set, a
nominal value of LΓ=0.7 was found to determine the boundary for
the occurrence of NPF, with NPF occurring when LΓ<0.7 and being
suppressed when LΓ>0.7. Moreover, nearly 45% of measured
LΓ values associated with NPF fell in the relatively narrow range
of 0.1<LΓ<0.3. |
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