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| Titel |
Distinguishing molecular characteristics of aerosol water soluble organic matter from the 2011 trans-North Atlantic US GEOTRACES cruise |
| VerfasserIn |
A. S. Wozniak, A. S. Willoughby, S. C. Gurganus, P. G. Hatcher |
| 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. 16 ; Nr. 14, no. 16 (2014-08-21), S.8419-8434 |
| Datensatznummer |
250118963
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| Publikation (Nr.) |
 copernicus.org/acp-14-8419-2014.pdf |
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| Zusammenfassung |
| The molecular characteristics of aerosol organic matter (OM) determines to a
large extent its impacts on the atmospheric radiative budget and ecosystem
function in terrestrial and aquatic environments, yet the OM molecular
details of aerosols from different sources are not well established. Aerosol
particulate samples with North American-influenced, North African-influenced,
and marine (minimal recent continental influence) air mass back trajectories
were collected as part of the 2011 trans-North Atlantic US GEOTRACES cruise
and analyzed for their water soluble OM (WSOM) molecular characteristics
using electrospray ionization Fourier transform ion cyclotron resonance mass
spectrometry. Principal component analysis (PCA) separated the samples into
five groups defined by distinct molecular formula characteristics. An
abundance of nitrogen containing compounds with molecular formulas consistent
with amino acid derivatives defined the two samples comprising the primary
marine group (henceforth referred to as Primary Marine), which suggest a
primary marine biological source to their WSOM in spite of their North
American-influenced air mass trajectories. A second group of samples (aged
marine, henceforth referred to as Aged Marine) with marine air mass
trajectories was characterized by an abundance of low O / C (0.15–0.45)
sulfur containing compounds consistent with organosulfate compounds formed
via secondary aging reactions in the atmosphere. Several samples having North
American-influenced air mass trajectories formed another group again
characterized by organosulfate and nitrooxyorganosulfate type compounds with
higher O / C ratios (0.5–1.0) than the Aged Marine samples reflecting the
combustion influence from the North American continent. All the samples with
North African-influenced air mass trajectories were grouped together in the
PCA and were characterized by a lack of heteroatom (N, S, P) containing
molecular formulas covering a wide O / C range (0.15–0.90) reflecting the
desert source of this WSOM. The two marine groups showed molecular formulas
that, on average, had higher H / C ratios and lower O / C ratios and
modified aromaticity indices than the two continentally influenced groups,
which suggests that these properties are characteristic of marine vs.
continental aerosol WSOM. The final sample group, the mixed source samples
(henceforth referred to as Mixed Source), showed intermediate molecular
characteristics, which suggests no dominant continental or marine source. The
source-specific OM details described here will aid efforts to link aerosol OM
source with molecular characteristics and impacts in the environment. |
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