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| Titel |
Secondary organic aerosol (SOA) formation from reaction of isoprene with nitrate radicals (NO3) |
| VerfasserIn |
N. L. Ng, A. J. Kwan, J. D. Surratt, A. W. H. Chan, P. S. Chhabra, A. Sorooshian, H. O. T. Pye, J. D. Crounse, P. O. Wennberg, R. C. Flagan, J. H. Seinfeld |
| 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 ; 8, no. 14 ; Nr. 8, no. 14 (2008-08-01), S.4117-4140 |
| Datensatznummer |
250006311
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| Publikation (Nr.) |
 copernicus.org/acp-8-4117-2008.pdf |
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| Zusammenfassung |
| Secondary organic aerosol (SOA) formation from the reaction of isoprene with
nitrate radicals (NO3) is investigated in the Caltech indoor chambers.
Experiments are performed in the dark and under dry conditions (RH<10%) using N2O5 as a source of NO3 radicals. For an
initial isoprene concentration of 18.4 to 101.6 ppb, the SOA yield (defined
as the ratio of the mass of organic aerosol formed to the mass of parent
hydrocarbon reacted) ranges from 4.3% to 23.8%. By examining the time
evolutions of gas-phase intermediate products and aerosol volume in real
time, we are able to constrain the chemistry that leads to the formation of
low-volatility products. Although the formation of ROOR from the reaction of
two peroxy radicals (RO2) has generally been considered as a minor
channel, based on the gas-phase and aerosol-phase data it appears that
RO2+RO2 reaction (self reaction or cross-reaction) in the gas
phase yielding ROOR products is a dominant SOA formation pathway. A wide
array of organic nitrates and peroxides are identified in the aerosol formed
and mechanisms for SOA formation are proposed. Using a uniform SOA yield of
10% (corresponding to Mo≅10 μg m−3), it is
estimated that ~2 to 3 Tg yr−1 of SOA results from isoprene+NO3. The extent to which the results from this study can be applied to
conditions in the atmosphere depends on the fate of peroxy radicals in the
nighttime troposphere. |
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