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Technical Note: Determination of formaldehyde mixing ratios in air with PTR-MS: laboratory experiments and field measurements.

Authors :
Inomata, S.
Tanimoto, H.
Kameyama, S.
Tsunogai, U.
H. Irie
Kanaya, Y.
Wang, Z.
Source :
Atmospheric Chemistry & Physics; 2008, Vol. 8 Issue 2, p273-284, 12p, 1 Chart, 6 Graphs
Publication Year :
2008

Abstract

Formaldehyde (HCHO), the most abundant carbonyl compound in the atmosphere, is generated as an intermediate product in the oxidation of nonmethane hydrocarbons. Proton transfer reaction mass spectrometry (PTR-MS) has the capability to detect HCHO from ion signals at m/z 31 with high time-resolution. However, the detection sensitivity is low compared to other detectable species, and is considerably affected by humidity, due to back reactions between protonated HCHO and water vapor prior to analysis. We performed a laboratory calibration of PTR-MS for HCHO and examined the detection sensitivity and humidity dependence at various field strengths. Subsequently, we deployed the PTR-MS instrument in a field campaign at Mount Tai in China in June 2006 to measure HCHO in various meteorological and photochemical conditions; we also conducted intercomparison measurements by Multi-Axis Differential Optical Absorption Spectroscopy (MAX-DOAS). Correction of interference in the m/z 31 signals by fragments from proton transfer reactions with methyl hydroperoxide, methanol, and ethanol greatly improves agreement between the two methods, giving the correlation [HCHO]<subscript>MAX-DOAS</subscript>=(0.99±0.16) [HCHO]<subscript>PTR-MS</subscript>+(0.02±0.38), where error limits represent 95% confidence levels. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
16807316
Volume :
8
Issue :
2
Database :
Complementary Index
Journal :
Atmospheric Chemistry & Physics
Publication Type :
Academic Journal
Accession number :
30092315
Full Text :
https://doi.org/10.5194/acp-8-273-2008