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| Titel |
Characterization of a volcanic ash episode in southern Finland caused by the Grimsvötn eruption in Iceland in May 2011 |
| VerfasserIn |
V.-M. Kerminen, J. V. Niemi, H. Timonen, M. Aurela, A. Frey, S. Carbone, S. Saarikoski, K. Teinilä, J. Hakkarainen, J. Tamminen, J. Vira, M. Prank, M. Sofiev, R. Hillamo |
| 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. 23 ; Nr. 11, no. 23 (2011-12-07), S.12227-12239 |
| Datensatznummer |
250010247
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| Publikation (Nr.) |
 copernicus.org/acp-11-12227-2011.pdf |
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| Zusammenfassung |
| The volcanic eruption of Grimsvötn in Iceland in May 2011 affected
surface-layer air quality at several locations in Northern Europe. In
Helsinki, Finland, the main pollution episode lasted for more than 8 h
around the noon of 25 May. We characterized this episode by relying on
detailed physical, chemical and optical aerosol measurements. The analysis
was aided by air mass trajectory calculations, satellite measurements, and
dispersion model simulations. During the episode, volcanic ash particles
were present at sizes from less than 0.5 μm up to sizes >10 μm.
The mass mean diameter of ash particles was a few μm in the Helsinki
area, and the ash enhanced PM10 mass concentrations up to several tens
of μg m−3. Individual particle analysis showed that some ash
particles appeared almost non-reacted during the atmospheric transportation,
while most of them were mixed with sea salt or other type of particulate
matter. Also sulfate of volcanic origin appeared to have been transported to
our measurement site, but its contribution to the aerosol mass was minor due
the separation of ash-particle and sulfur dioxide plumes shortly after the
eruption. The volcanic material had very little effect on PM1 mass
concentrations or sub-micron particle number size distributions in the
Helsinki area. The aerosol scattering coefficient was increased and
visibility was slightly decreased during the episode, but in general changes
in aerosol optical properties due to volcanic aerosols seem to be difficult
to be distinguished from those induced by other pollutants present in a
continental boundary layer. The case investigated here demonstrates clearly
the power of combining surface aerosol measurements, dispersion model
simulations and satellite measurements in analyzing surface air pollution
episodes caused by volcanic eruptions. None of these three approaches alone
would be sufficient to forecast, or even to unambiguously identify, such
episodes. |
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