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| Titel |
Ambient measurements of aromatic and oxidized VOCs by PTR-MS and GC-MS: intercomparison between four instruments in a boreal forest in Finland |
| VerfasserIn |
M. K. Kajos, P. Rantala, M. Hill, H. Hellén, J. Aalto, J. Patokoski, R. Taipale, C. C. Hoerger, S. Reimann, T. M. Ruuskanen, J. Rinne, T. Petäjä |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1867-1381
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Measurement Techniques ; 8, no. 10 ; Nr. 8, no. 10 (2015-10-22), S.4453-4473 |
| Datensatznummer |
250116648
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| Publikation (Nr.) |
 copernicus.org/amt-8-4453-2015.pdf |
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| Zusammenfassung |
| Proton transfer reaction mass spectrometry (PTR-MS) and gas chromatography
mass spectrometry GC-MS) are commonly used methods for automated in situ
measurements of various volatile organic compounds (VOCs) in the atmosphere.
In order to investigate the reliability of such measurements, we operated
four automated analyzers using their normal field measurement protocol side
by side at a boreal forest site. We measured methanol, acetaldehyde, acetone,
benzene and toluene by two PTR-MS and two GC-MS instruments. The measurements
were conducted in southern Finland between 13 April and 14 May 2012. This
paper presents correlations and biases between the concentrations measured
using the four instruments. A very good correlation was found for benzene and
acetone measurements between all instruments (the mean R value was 0.88 for
both compounds), while for acetaldehyde and toluene the correlation was
weaker (with a mean R value of 0.50 and 0.62, respectively). For some
compounds, notably for methanol, there were considerable systematic
differences in the mixing ratios measured by the different instruments,
despite the very good correlation between the instruments (mean R = 0.90).
The systematic difference manifests as a difference in the linear regression
slope between measurements conducted between instruments, rather than as an
offset. This mismatch indicates that the systematic uncertainty in the
sensitivity of a given instrument can lead to an uncertainty of 50–100 %
in the methanol emissions measured by commonly used methods. |
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