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| Titel |
Airborne formaldehyde measurements using PTR-MS: calibration, humidity dependence, inter-comparison and initial results |
| VerfasserIn |
C. Warneke, P. Veres, J. S. Holloway, J. Stutz, C. Tsai, S. Alvarez, B. Rappenglueck, F. C. Fehsenfeld, M. Graus, J. B. Gilman, J. A. Gouw |
| 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 ; 4, no. 10 ; Nr. 4, no. 10 (2011-10-31), S.2345-2358 |
| Datensatznummer |
250002128
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| Publikation (Nr.) |
 copernicus.org/amt-4-2345-2011.pdf |
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| Zusammenfassung |
| We present quantitative, fast time response measurements of formaldehyde
(HCHO) onboard an aircraft using a Proton-Transfer-Reaction
Mass-Spectrometry (PTR-MS) instrument. The HCHO measurement by PTR-MS is
strongly humidity dependent and therefore airborne measurements are
difficult and have not been reported. The PTR-MS instrument was run in the
standard PTR-MS operating mode (de Gouw and Warneke, 2007), where about
15 volatile organic compounds (VOCs) are measured together with HCHO onboard
the NOAA WP-3 aircraft during the CalNex 2010 campaign in California. We
compare the humidity dependence determined in the laboratory with in-flight
calibrations of HCHO and calculate the HCHO mixing ratio during all flights
using the results from both. The detection limit (S/N = 1) for HCHO was
between 100 pptv in the dry free troposphere and 300 pptv in the humid
marine boundary layer for a one second acquisition time every 17 s.
The PTR-MS measurements are compared with HCHO measurements using a DOAS
instrument and a Hantzsch monitor at a ground site in Pasadena. The PTR-MS
agreed with the DOAS within the stated uncertainties and was just outside
the uncertainties with the Hantzsch. We also compare HCHO enhancement ratios
in the Los Angeles basin and in the free troposphere with literature values
and find good agreement. The usefulness of the PTR-MS HCHO measurements in
atmospheric observations is demonstrated by following an isolated
anthropogenic plume. The photochemical production of HCHO can be observed
simultaneously with production of acetaldehyde and the photochemical
degradation of aromatic compounds using the PTR-MS. The results show that
PTR-MS seems a useful instrument to measure HCHO, but more inter-comparisons
are needed. |
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