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| Titel |
Ambient measurements of biological aerosol particles near Killarney, Ireland: a comparison between real-time fluorescence and microscopy techniques |
| VerfasserIn |
D. A. Healy, J. A. Huffman, D. J. O'Connor, C. Pöhlker, U. Pöschl, J. R. Sodeau |
| 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. 15 ; Nr. 14, no. 15 (2014-08-13), S.8055-8069 |
| Datensatznummer |
250118940
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| Publikation (Nr.) |
 copernicus.org/acp-14-8055-2014.pdf |
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| Zusammenfassung |
Primary biological aerosol particles (PBAPs) can contribute significantly to
the coarse particle burden in many environments. PBAPs can thus influence
climate and precipitation systems as cloud nuclei and can spread disease to
humans, animals, and plants. Measurement data and techniques for PBAPs in
natural environments at high time- and size resolution are, however, sparse,
and so large uncertainties remain in the role that biological particles play
in the Earth system. In this study two commercial real-time fluorescence
particle sensors and a Sporewatch single-stage particle impactor were
operated continuously from 2 August to 2 September 2010 at a rural sampling
location in Killarney National Park in southwestern Ireland. A cascade
impactor was operated periodically to collect size-resolved particles during
exemplary periods. Here we report the first ambient comparison of a
waveband integrated bioaerosol sensor (WIBS-4) with a ultraviolet
aerodynamic particle sizer (UV-APS) and also compare these real-time
fluorescence techniques with results of fluorescence and optical microscopy
of impacted samples. Both real-time instruments showed qualitatively similar
behavior, with increased fluorescent bioparticle concentrations at night,
when relative humidity was highest and temperature was lowest.
The fluorescent particle number from the FL3 channel of the WIBS-4 and from
the UV-APS were strongly correlated and dominated by a 3 μm mode in
the particle size distribution. The WIBS FL2 channel exhibited particle
modes at approx. 1 and 3 μm, and each was correlated with the
concentration of fungal spores commonly observed in air samples collected at
the site (ascospores, basidiospores, Ganoderma spp.). The WIBS FL1 channel exhibited
variable multimodal distributions turning into a broad featureless single
mode after averaging, and exhibited poor correlation with fungal spore
concentrations, which may be due to the detection of bacterial and
non-biological fluorescent particles. Cladosporium spp., which are among the most abundant
fungal spores in many terrestrial environments, were not correlated with any
of the real-time fluorescence channels, suggesting that the real-time
fluorescence instruments are relatively insensitive to PBAP classes with
dark, highly absorptive cell walls.
Fluorescence microscopy images of cascade impactor plates showed large
numbers of coarse-mode particles consistent with the morphology and weak
fluorescence expected of sea salt. Some of these particles were attached to
biological cells, suggesting that a marine source influenced the PBAPs
observed at the site and that the ocean may be an important contributor to
PBAP loadings in coastal environments. |
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