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| Titel |
Laboratory investigation of photochemical oxidation of organic aerosol from wood fires 2: analysis of aerosol mass spectrometer data |
| VerfasserIn |
A. P. Grieshop, 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. 6 ; Nr. 9, no. 6 (2009-03-27), S.2227-2240 |
| Datensatznummer |
250007106
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| Publikation (Nr.) |
 copernicus.org/acp-9-2227-2009.pdf |
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| Zusammenfassung |
| Experiments were conducted to investigate the effects of photo-oxidation on
organic aerosol (OA) in dilute wood smoke by exposing emissions from soft-
and hard-wood fires to UV light in a smog chamber. This paper focuses on
changes in OA composition measured using a unit-mass-resolution quadrupole
Aerosol Mass Spectrometer (AMS). The results highlight how photochemical
processing can lead to considerable evolution of the mass, volatility and
level of oxygenation of biomass-burning OA. Photochemical oxidation produced
substantial new OA, more than doubling the OA mass after a few hours of
aging under typical summertime conditions. Aging also decreased the
volatility of the OA and made it progressively more oxygenated. The results
also illustrate strengths of, and challenges with, using AMS data for
source apportionment analysis. For example, the mass spectra of fresh and
aged BBOA are distinct from fresh motor-vehicle emissions. The mass spectra
of the secondary OA produced from aging wood smoke are very similar to those
of the oxygenated OA (OOA) that dominates ambient AMS datasets, further
reinforcing the connection between OOA and OA formed from photo-chemistry.
In addition, aged wood smoke spectra are similar to those from OA created by
photo-oxidizing dilute diesel exhaust. This demonstrates that the OOA
observed in the atmosphere can be produced by photochemical aging of dilute
emissions from different types of combustion systems operating on fuels with
modern or fossil carbon. Since OOA is frequently the dominant component of
ambient OA, the similarity of spectra of aged emissions from different
sources represents an important challenge for AMS-based source apportionment
studies. |
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