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| Titel |
Laboratory investigation of photochemical oxidation of organic aerosol from wood fires 1: measurement and simulation of organic aerosol evolution |
| VerfasserIn |
A. P. Grieshop, J. M. Logue, N. M. Donahue, A. L. Robinson |
| 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. 4 ; Nr. 9, no. 4 (2009-02-18), S.1263-1277 |
| Datensatznummer |
250006925
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| Publikation (Nr.) |
 copernicus.org/acp-9-1263-2009.pdf |
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| Zusammenfassung |
| Experiments were conducted to investigate the effects of photo-oxidation on
organic aerosol (OA) emissions from flaming and smoldering hard- and
soft-wood fires under plume-like conditions. This was done by exposing the
dilute emissions from a small wood stove to UV light in a smog chamber and
measuring the gas- and particle-phase pollutant concentrations with a suite
of instruments including a Proton Transfer Reaction Mass Spectrometer
(PTR-MS), an Aerosol Mass Spectrometer (AMS) and a thermodenuder. The
measurements highlight how atmospheric processing can lead to considerable
evolution of the mass and volatility of biomass-burning OA. Photochemical
oxidation produced substantial new OA, increasing concentrations by a factor
of 1.5 to 2.8 after several hours of exposure to typical summertime hydroxyl
radical (OH) concentrations. Less than 20% of this new OA could be
explained using a state-of-the-art secondary organic aerosol model and the
measured decay of traditional SOA precursors. The thermodenuder data
indicate that the primary OA is semivolatile; at 50°C between 50 and
80% of the fresh primary OA evaporated. Aging reduced the volatility of
the OA; at 50°C only 20 to 40% of aged OA evaporated. The
predictions of a volatility basis-set model that explicitly tracks the
partitioning and aging of low-volatility organics was compared to the chamber
data. The OA production can be explained by the oxidation of low-volatility
organic vapors; the model can also reproduce observed changes in OA
volatility and composition. The model was used to investigate the
competition between photochemical processing and dilution on OA
concentrations in plumes. |
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