Intercomparison of Two Hydroxyl Radical Measurement Techniques at the Atmosphere Simulation Chamber SAPHIR

Schlosser, Eric; Bohn, Birger; Brauers, T.; Dorn, Hans-Peter; Fuchs, Hendrik; Häseler, R.; Hofzumahaus, A.; Holland, F.; Rohrer, Franz; Rupp, L.; Siese, M.; Tillmann, Ralf; Wahner, Andreas

doi:10.1007/s10874-006-9049-3

Cited by 84 publications

(98 citation statements)

References 22 publications

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“…One air spectrum is recorded within 135 s. A comparison of measured and modelled MCST spectra is given by Hausmann et al (1997) who found a maximum 1.7% error contribution to the accuracy of the measurement. The deconvolution of the measured spectrum is performed by fitting a trigonometric background consisting of 16 terms and three reference spectra, namely OH, HCHO, and an so far unidentified absorber X (Schlosser et al, 2006). We present the HCHO data in units of the optical density (absorbance) at 308.1034 nm (see Fig.…”

Section: High-resolution Doas Instrumentmentioning

confidence: 99%

“…Multiple reflection cells, however, allow the setup of DOAS measurements with long light paths inside simulation chambers of different sizes (e.g. De Haan et al, 1999;Kleffmann et al, 2006;Schlosser et al, 2006;Bossmeyer, 2006).…”

Section: Introductionmentioning

confidence: 99%

“…An effective cross section for broad-band-DOAS can be calculated using any of these cross sections by convolution with an appropriate instrument function. For the high-resolution DOAS (HR-DOAS) instrument designed to detect tropospheric OH radicals (Hausmann et al, 1997;Brauers et al, 2001;Schlosser et al, 2006) no literature data at sufficiently high spectral resolution (2.7 pm) is available. However, a comparison between the highest resolution literature data of Smith et al (2006) and the HR-DOAS data is given in the discussion of this paper .…”

Section: Introductionmentioning

confidence: 99%

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Investigation of the formaldehyde differential absorption cross section at high and low spectral resolution in the simulation chamber SAPHIR

Brauers¹,

Bossmeyer²,

Dorn³

et al. 2007

Atmos. Chem. Phys.

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Abstract.The results from a simulation chamber study on the formaldehyde (HCHO) absorption cross section in the UV spectral region are presented. We performed 4 experiments at ambient HCHO concentrations with simultaneous measurements of two DOAS instruments in the atmosphere simulation chamber SAPHIR in Jülich. The two instruments differ in their spectral resolution, one working at 0.2 nm (broad-band, BB-DOAS), the other at 2.7 pm (high-resolution, HR-DOAS). Both instruments use dedicated multi reflection cells to achieve long light path lengths of 960 m and 2240 m, respectively, inside the chamber. During two experiments HCHO was injected into the clean chamber by thermolysis of well defined amounts of paraformaldehyde reaching mixing rations of 30 ppbV at maximum. The HCHO concentration calculated from the injection and the chamber volume agrees with the BB-DOAS measured value when the absorption cross section of Meller and Moortgat (2000) and the temperature coefficient of Cantrell (1990) were used for data evaluation. In two further experiments we produced HCHO in-situ from the ozone + ethene reaction which was intended to provide an independent way of HCHO calibration through the measurements of ozone and ethene. However, we found an unexpected deviation from the current understanding of the ozone + ethene reaction when CO was added to suppress possible oxidation of ethene by OH radicals. The reaction of the Criegee intermediate with CO could be 240 times slower than currently assumed. Based on the BB-DOAS measurements we could deduce a high-resolution cross section for HCHO which was not measured directly so far.

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Section: High-resolution Doas Instrumentmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Investigation of the formaldehyde differential absorption cross section at high and low spectral resolution in the simulation chamber SAPHIR

Brauers¹,

Bossmeyer²,

Dorn³

et al. 2007

Atmos. Chem. Phys.

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“…From these measurements, concentrations of HO 2 and RO 2 radicals were determined. Moreover, differential optical absorption spectroscopy (DOAS) (Dorn et al, 1995;Schlosser et al, 2007Schlosser et al, , 2009) was employed for the measurement of OH radical concentrations.…”

Section: Analytical Instrumentationmentioning

confidence: 99%

Atmospheric photochemistry of aromatic hydrocarbons: OH budgets during SAPHIR chamber experiments

et al. 2014

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Abstract. Current photochemical models developed to simulate the atmospheric degradation of aromatic hydrocarbons tend to underestimate OH radical concentrations. In order to analyse OH budgets, we performed experiments with benzene, toluene, p-xylene and 1,3,5-trimethylbenzene in the atmosphere simulation chamber SAPHIR. Experiments were conducted under low-NO conditions (typically 0.1-0.2 ppb) and high-NO conditions (typically 7-8 ppb), and starting concentrations of 6-250 ppb of aromatics, dependent on OH rate constants. For the OH budget analysis a steady-state approach was applied in which OH production and destruction rates (P OH and D OH ) have to be equal. The P OH were determined from measurements of HO 2 , NO, HONO, and O 3 concentrations, considering OH formation by photolysis and recycling from HO 2 . The D OH were calculated from measurements of the OH concentrations and total OH reactivities. The OH budgets were determined from D OH /P OH ratios. The accuracy and reproducibility of the approach were assessed in several experiments using CO as a reference compound where an average ratio D OH /P OH = 1.13 ± 0.19 was obtained. In experiments with aromatics, these ratios ranged within 1.1-1.6 under low-NO conditions and 0.9-1.2 under high-NO conditions. The results indicate that OH budgets during photo-oxidation experiments with aromatics are balanced within experimental accuracies. Inclusion of a further, recently proposed OH production via HO 2 + RO 2 reactions led to improvements under low-NO conditions but the differences were small and insignificant within the experimental errors.

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“…It provides a large volume of homogeneously mixed air, to which trace gases can be added at tropospheric concentration levels. For instrumental comparisons, it ensures that the instruments sample air of the same composition and at natural conditions, as was demonstrated for OH (Schlosser et al, 2007) and oxygenated volatile organic compounds (Apel et al, 2008). A further advantage of the use of a chamber is that experiments can be carried out at controlled conditions, allowing, for example, to keep radical concentrations constant at different levels.…”

Section: Introductionmentioning

confidence: 99%

Intercomparison of peroxy radical measurements obtained at atmospheric conditions by laser-induced fluorescence and electron spin resonance spectroscopy

Fuchs

Brauers²,

Häseler³

et al. 2009

Atmos. Meas. Tech.

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Abstract. Measurements of hydroperoxy radical (HO 2 ) and organic peroxy radical (RO 2 ) concentrations were performed by two different techniques in the atmospheric simulation chamber SAPHIR in Jülich, Germany. 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 σ ). The other technique, ROxLIF, has been newly developed. It is based on the selective chemical conversion of RO x radicals (HO 2 and RO 2 ) to OH, which is detected with high sensitivity by laser-induced fluorescence (LIF). ROx-LIF is calibrated by quantitative photolysis of water vapor at 185 nm and provides ambient measurements at a temporal resolution of 1 min and accuracy of 20% (2 σ ). The measurements of HO 2 and RO 2 obtained by the two techniques were compared for two types of atmospheric simulation experiments. In one experiment, HO 2 and CH 3 O 2 radicals were produced by photooxidation of methane in air at tropospheric conditions. In the second experiment, HO 2 and C 2 H 5 O 2 were produced by ozonolysis of 1-butene in air at dark conditions. The radical concentrations were within the range of 16 to 100 pptv for HO 2 and 12 to 45 pptv for RO 2 . Good agreement was found in the comparison of the ROxLIF and MIESR measurements within their combined experimental uncertainties. Linear regressions to the combined data set yield slopes of 1.02±0.13 (1 σ ) for RO 2 and 0.98±0.08 (1 σ ) for HO 2 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.

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Intercomparison of Two Hydroxyl Radical Measurement Techniques at the Atmosphere Simulation Chamber SAPHIR

Cited by 84 publications

References 22 publications

Investigation of the formaldehyde differential absorption cross section at high and low spectral resolution in the simulation chamber SAPHIR

Investigation of the formaldehyde differential absorption cross section at high and low spectral resolution in the simulation chamber SAPHIR

Atmospheric photochemistry of aromatic hydrocarbons: OH budgets during SAPHIR chamber experiments

Intercomparison of peroxy radical measurements obtained at atmospheric conditions by laser-induced fluorescence and electron spin resonance spectroscopy

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