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| Titel |
Kinetic modeling of nucleation experiments involving SO2 and OH: new insights into the underlying nucleation mechanisms |
| VerfasserIn |
H. Du, F. Yu |
| 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 ; 9, no. 20 ; Nr. 9, no. 20 (2009-10-22), S.7913-7922 |
| Datensatznummer |
250007700
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| Publikation (Nr.) |
 copernicus.org/acp-9-7913-2009.pdf |
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| Zusammenfassung |
| Nucleation is an important source of atmospheric aerosols
which have significant climatic and health implications. Despite intensive
theoretical and field studies over the past decades, the dominant
nucleation mechanism in the lower troposphere remains to be mysterious.
Several recent laboratory studies on atmospheric nucleation may shed light
on this important problem. However, the most interesting finding from those
studies was based on the derived H2SO4 concentration whose
accuracy has not yet been evaluated by any other means. Moreover, the
threshold H2SO4 concentration needed to reach the same degree of
nucleation reported by two separate nucleation studies varies by about one
order of magnitude. In this study, we apply a recently updated kinetic
nucleation model to study the nucleation phenomena observed in those recent
experiments. We show that the H2SO4 concentration can be estimated
with a higher level of accuracy with the kinetic model by constraining the
simulated particle size distributions with observed ones. We find that the
required H2SO4 concentrations to achieve the best agreement
between modeling and measurements are a factor of ~2 to 4 higher than
reported in those experiments. More importantly, by comparing the derived
thermodynamic properties associated with the nucleation process, we conclude
that different unknown species may participate in the two separate
nucleation experimental studies, which may explain the large difference in
the reported threshold H2SO4 concentration. Although the unknown
species involved has yet to be identified, the derived values of
thermodynamic properties can serve as a valuable guideline for the search of
their chemical identities using advanced quantum-chemical approaches. |
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