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| Titel |
Airborne measurements of the spatial distribution of aerosol chemical composition across Europe and evolution of the organic fraction |
| VerfasserIn |
W. T. Morgan, J. D. Allan, K. N. Bower, E. J. Highwood, D. Liu, G. R. McMeeking, M. J. Northway, P. I. Williams, R. Krejci, H. Coe |
| 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 ; 10, no. 8 ; Nr. 10, no. 8 (2010-04-29), S.4065-4083 |
| Datensatznummer |
250008390
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| Publikation (Nr.) |
 copernicus.org/acp-10-4065-2010.pdf |
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| Zusammenfassung |
| The spatial distribution of aerosol chemical composition and
the evolution of the Organic Aerosol (OA) fraction is investigated based upon
airborne measurements of aerosol chemical composition in the planetary
boundary layer across Europe. Sub-micron aerosol chemical composition was
measured using a compact Time-of-Flight Aerosol Mass Spectrometer (cToF-AMS).
A range of sampling conditions were evaluated, including relatively clean
background conditions, polluted conditions in North-Western Europe and the
near-field to far-field outflow from such conditions. Ammonium nitrate and OA
were found to be the dominant chemical components of the sub-micron aerosol
burden, with mass fractions ranging from 20–50% each. Ammonium nitrate was
found to dominate in North-Western Europe during episodes of high pollution,
reflecting the enhanced NOx and ammonia sources in this region. OA
was ubiquitous across Europe and concentrations generally exceeded sulphate
by 30–160%. A factor analysis of the OA burden was performed in order to
probe the evolution across this large range of spatial and temporal scales.
Two separate Oxygenated Organic Aerosol (OOA) components were identified; one
representing an aged-OOA, termed Low Volatility-OOA and another representing
fresher-OOA, termed Semi Volatile-OOA on the basis of their mass spectral
similarity to previous studies. The factors derived from different flights
were not chemically the same but rather reflect the range of OA composition
sampled during a particular flight. Significant chemical processing of the OA
was observed downwind of major sources in North-Western Europe, with the
LV-OOA component becoming increasingly dominant as the distance from source
and photochemical processing increased. The measurements suggest that the
aging of OA can be viewed as a continuum, with a progression from a less
oxidised, semi-volatile component to a highly oxidised, less-volatile
component. Substantial amounts of pollution were observed far downwind of
continental Europe, with OA and ammonium nitrate being the major constituents
of the sub-micron aerosol burden. Such anthropogenically perturbed air masses
can significantly perturb regional climate far downwind of major source
regions. |
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