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| Titel |
Intercomparison of peroxy radical measurements by laser-induced fluorescence and electron spin resonance spectroscopy at the atmosphere simulation chamber SAPHIR |
| VerfasserIn |
H. Fuchs, T. Brauers, R. Häseler, F. Holland, D. Mihelcic, P. Müsgen, F. Rohrer, R. Wegener, A. Hofzumahaus |
| Konferenz |
EGU General Assembly 2009
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250027577
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| Zusammenfassung |
| Two experiments were carried out at the atmosphere simulation chamber SAPHIR in Jülich,
Germany, in order to compare measurements of atmospheric hydroperoxy radical (HO2) and
organic peroxy radical (RO2) concentrations by two different techniques. The first
technique was the well-established Matrix Isolation Electron Spin Resonance (MIESR),
which provides absolute measurements with a time resolution of 30 min and high
accuracy (10 %, 2 Ï). The second was the newly developed ROxLIF instrument, which
detects peroxy radical at a temporal resolution of 1 min and an accuracy of 20 %
(2 Ï). It is based on the selective chemical conversion of ROX radicals (HO2 and
RO2) to OH, which is detected with high sensitivity by laser-induced fluorescence
(LIF). Quantitative photolysis of water vapor at 185 nm is used in order to calibrate
measurements of the ROxLIF instrument. Two complementary types of atmospheric
simulation experiments were carried out, during which atmospheric concentrations of
peroxy radicals within the range of 16 to 100 pptv for HO2 and 12 to 45 pptv for RO2
were produced. In one experiment, HO2 and CH3O2 radicals were produced by
photooxidation of methane in air. In the second experiment, HO2 and C2H5O2 were
produced by ozonolysis of 1-butene in air at dark conditions. Measurements of both
instruments, ROxLIF and MIESR exhibit good agreement within their combined
experimental uncertainties. Linear regressions to the combined data set yield slopes of
1.02 ± 0.13(1Ï) for RO2 and 0.98 ± 0.08(1Ï) for HO2 without significant offsets. The
results confirm the calibration of the ROxLIF instrument and demonstrate that it can
be applied with good accuracy for measurements of atmospheric peroxy radical
concentrations. H. Fuchs et al, Atmos. Meas. Tech. Discuss., 1, 375-399, 2008. |
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