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| Titel |
Molecular corridors and kinetic regimes in the multiphase chemical evolution of secondary organic aerosol |
| VerfasserIn |
M. Shiraiwa, T. Berkemeier, K. A. Schilling-Fahnestock, J. H. Seinfeld, U. Pöschl |
| 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. 16 ; Nr. 14, no. 16 (2014-08-20), S.8323-8341 |
| Datensatznummer |
250118958
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| Publikation (Nr.) |
 copernicus.org/acp-14-8323-2014.pdf |
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| Zusammenfassung |
| The dominant component of atmospheric, organic aerosol is that derived from
the oxidation of volatile organic compounds (VOCs), so-called secondary
organic aerosol (SOA). SOA consists of a multitude of organic compounds,
only a small fraction of which has historically been identified. Formation
and evolution of SOA is a complex process involving coupled chemical
reaction and mass transport in the gas and particle phases. Current SOA
models do not embody the full spectrum of reaction and transport processes,
nor do they identify the dominant rate-limiting steps in SOA formation.
Based on molecular identification of SOA oxidation products, we show here
that the chemical evolution of SOA from a variety of VOC precursors adheres
to characteristic "molecular corridors" with a tight inverse correlation
between volatility and molar mass. The slope of these corridors corresponds
to the increase in molar mass required to decrease volatility by one order
of magnitude (-dM / dlogC0). It varies in the range of
10–30 g mol−1, depending on the molecular size of the SOA precursor and the O : C ratio of
the reaction products. Sequential and parallel reaction pathways of
oxidation and dimerization or oligomerization progressing along these
corridors pass through characteristic regimes of reaction-, diffusion-, or
accommodation-limited multiphase chemical kinetics that can be classified
according to reaction location, degree of saturation, and extent of
heterogeneity of gas and particle phases. The molecular corridors and
kinetic regimes help to constrain and describe the properties of the
products, pathways, and rates of SOA evolution, thereby facilitating the
further development of aerosol models for air quality and climate. |
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