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| Titel |
Primary and secondary biomass burning aerosols determined by proton nuclear magnetic resonance (1H-NMR) spectroscopy during the 2008 EUCAARI campaign in the Po Valley (Italy) |
| VerfasserIn |
M. Paglione, S. Saarikoski, S. Carbone, R. Hillamo, M. C. Facchini, E. Finessi, L. Giulianelli, C. Carbone, S. Fuzzi, F. Moretti, E. Tagliavini, E. Swietlicki, K. Eriksson Stenström, A. S. H. Prévôt, P. Massoli, M. Canaragatna, D. Worsnop, S. Decesari |
| 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. 10 ; Nr. 14, no. 10 (2014-05-23), S.5089-5110 |
| Datensatznummer |
250118733
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| Publikation (Nr.) |
 copernicus.org/acp-14-5089-2014.pdf |
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| Zusammenfassung |
| Atmospheric organic aerosols are
generally classified as primary and secondary (POA and SOA) according to
their formation processes. An actual separation, however, is challenging when
the timescales of emission and gas-to-particle formation overlap. The
presence of SOA formation in biomass burning plumes leads to scientific
questions about whether the oxidized fraction of biomass burning aerosol is
rather of secondary or primary origin, as some studies would suggest, and
about the chemical compositions of oxidized biomass burning POA and SOA. In
this study, we apply nuclear magnetic resonance (NMR) spectroscopy to
investigate the functional group composition of fresh and aged biomass
burning aerosols during an intensive field campaign in the Po Valley, Italy.
The campaign was part of the EUCAARI project and was held at the rural
station of San Pietro Capofiume in spring 2008. Factor analysis applied to
the set of NMR spectra was used to apportion the wood burning contribution
and other organic carbon (OC) source contributions, including aliphatic
amines. Our NMR results, referred to the polar, water-soluble fraction of OC,
show that fresh wood burning particles are composed of polyols and aromatic
compounds, with a sharp resemblance to wood burning POA produced in wood
stoves, while aged samples are clearly depleted of alcohols and are enriched
in aliphatic acids with a smaller contribution of aromatic compounds. The
comparison with biomass burning organic aerosols (BBOA) determined by
high-resolution aerosol mass spectrometry (HR-TOF-AMS) at the site shows only
a partial overlap between NMR BB-POA and AMS BBOA, which can be explained by
either the inability of BBOA to capture all BB-POA composition, especially
the alcohol fraction, or the fact that BBOA account for insoluble organic
compounds unmeasured by the NMR. Therefore, an unambiguous composition for
biomass burning POA could not be derived from this study, with NMR analysis
indicating a higher O / C ratio compared to that measured for AMS BBOA. The
comparison between the two techniques substantially improves when adding
factors tracing possible contributions from biomass burning SOA, showing that
the operational definitions of biomass burning organic aerosols are more
consistent between techniques when including more factors tracing chemical
classes over a range of oxidation levels. Overall, the non-fossil total
carbon fraction was 50–57%, depending on the assumptions about the
14C content of non-fossil carbon, and the fraction of organic carbon
estimated to be oxidized organic aerosol (OOA) from HR-TOF-AMS measurements
was 73–100% modern. |
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