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| Titel |
Sources of carbonaceous aerosol in the Amazon basin |
| VerfasserIn |
S. Gilardoni, E. Vignati, E. Marmer, F. Cavalli, C. Belis, V. Gianelle, A. Loureiro, P. Artaxo |
| 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 ; 11, no. 6 ; Nr. 11, no. 6 (2011-03-24), S.2747-2764 |
| Datensatznummer |
250009518
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| Publikation (Nr.) |
 copernicus.org/acp-11-2747-2011.pdf |
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| Zusammenfassung |
The quantification of sources of carbonaceous aerosol is important to
understand their atmospheric concentrations and regulating processes and to
study possible effects on climate and air quality, in addition to develop
mitigation strategies.
In the framework of the European Integrated Project on Aerosol Cloud Climate Interactions (EUCAARI)
fine (Dp < 2.5 μm) and coarse (2.5 μm < Dp
<10 μm) aerosol particles were sampled from February to June (wet
season) and from August to September (dry season) 2008 in the central Amazon
basin. The mass of fine particles averaged 2.4 μg m−3 during
the wet season and 4.2 μg m−3 during the dry season. The
average coarse aerosol mass concentration during wet and dry periods was 7.9
and 7.6 μg m−3, respectively. The overall chemical composition
of fine and coarse mass did not show any seasonality with the largest
fraction of fine and coarse aerosol mass explained by organic carbon (OC);
the average OC to mass ratio was 0.4 and 0.6 in fine and coarse aerosol
modes, respectively. The mass absorbing cross section of soot was determined
by comparison of elemental carbon and light absorption coefficient
measurements and it was equal to 4.7 m2 g−1 at 637 nm. Carbon
aerosol sources were identified by Positive Matrix Factorization (PMF)
analysis of thermograms: 44% of fine total carbon mass was assigned to
biomass burning, 43% to secondary organic aerosol (SOA), and 13% to
volatile species that are difficult to apportion. In the coarse mode, primary
biogenic aerosol particles (PBAP) dominated the carbonaceous aerosol mass.
The results confirmed the importance of PBAP in forested areas.
The source apportionment results were employed to evaluate the ability of
global chemistry transport models to simulate carbonaceous aerosol sources in
a regional tropical background site. The comparison showed an overestimation
of elemental carbon (EC) by the TM5 model during the dry season and OC both
during the dry and wet periods. The overestimation was likely due to the
overestimation of biomass burning emission inventories and SOA production
over tropical areas. |
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