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| Titel |
Formation of Secondary Organic Aerosol from Non-traditional Intermediate Volatility Organic Compounds |
| VerfasserIn |
N. M. Donahue, A. A. Presto, A. L. Robinson, J. H. Kroll, D. R. Worsnop |
| Konferenz |
EGU General Assembly 2009
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250027600
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| Zusammenfassung |
| Secondary organic aerosol (SOA) formation from ‘traditional’ precursors such as
monoterpenes and alkylbenzenes has received substantial attention for the past decade. These
traditional sources have relatively high emissions into the atmosphere, but they are also
relatively volatile. As a consequence, the oxidation products from those precursors must be
more than one million times less volatile in order to form SOA. We have recently begun to
investigate the role of ‘nontraditional’ SOA precursors with much lower volatility than the
traditional precursors. These intermediate volatility organic compounds (IVOC) are typically
co-emitted with traditional primary organic aerosol (POA) sources at elevated temperatures,
including biomass burning and internal combustion processes. While their emissions are
much lower than the traditional precursors, the volatility reduction required of the
reaction products is much less drastic, making high-yield SOA formation much more
likely.
Here we describe the formation of SOA from two precursors in the CMU environmental
chamber – heptadecane and pentacosane – under high- and low-NOx conditions. Analysis of
the resulting SOA with a high-resolution aerosol mass spectrometer coupled to a
thermodenuder allows us to asses the oxidation state and volatility distribution of the
condensible products, revealing a high degree of oxidation under high-NOx conditions where
most of the organics remain in the vapor phase for at least 2 generations of oxidation
chemistry, but a lower (though progressive) degree of oxidation under other conditions. These
results will be place in context using a two-dimensional volatility basis set that incorporates
both the volatility distribution and oxidation state of complex organic mixtures. |
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