Technical note: Measuring tropospheric OH and HO&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt; by laser-induced fluorescence at low pressure. A comparison of calibration  techniques

Dusanter, Sébastien; Vimal, D.; Stevens, P. S.

doi:10.5194/acp-8-321-2008

Cited by 72 publications

(112 citation statements)

References 61 publications

Supporting

Mentioning

109

Contrasting

Order By: Relevance

“…Given the potentially rapid reaction of Criegee intermediates with water vapor (Chao et al, 2015), this may suggest that the source of their interference was also the decomposition of Criegee intermediates inside their detection cell. However, Dusanter et al (2008) found that the instrument sensitivities derived from the ozone-alkene calibration technique using trans-2-butene were systematically lower than those derived from the water-vapor UV-photolysis technique, in contrast to what might be expected if the measurements from the ozonolysis technique were impacted by an interference from Criegee intermediates. But because these ozonolysis experiments were done under humid conditions, it is possible that the Criegee intermediates were scavenged by water vapor prior to entering the IU-FAGE detection cell, thus minimizing the interference.…”

Section: Interference From Criegee Intermediate Decomposition On Lif-mentioning

confidence: 46%

“…2) and both the 0.6 and 1 mm nozzle diameters, resulting in cell pressures of 4-7 Torr depending on the nozzle diameter size and pumping efficiency (Lew et al, 2017a). The error associated with the UV-water photolysis calibration technique is estimated to be ±36 % (2σ ; Dusanter et al, 2008).…”

Section: Detection Of Oh Radicalsmentioning

confidence: 99%

“…The sensitivity of the IU-FAGE instrument was calibrated using the UV-water photolysis technique where water vapor is photolyzed to produce known amounts of OH (Dusanter et al, 2008). In these experiments, calibrations were performed under the conditions of the experiments using N 2 , resulting in larger calibration factors compared to ambient air due to fluorescence quenching by oxygen.…”

Section: Detection Of Oh Radicalsmentioning

confidence: 99%

“…OH radicals were measured using the IU-FAGE instrument, in which ambient air is pulled through either a 0.6 or 1 mm diameter nozzle and expanded to a total pressure of approximately 4-9 Torr resulting in a total flow rate of approximately 3-10 SLPM (Dusanter et al, 2008(Dusanter et al, , 2009Griffith et al, 2013Griffith et al, , 2016. Previous field measurements using the IU-FAGE instrument have incorporated a cylindrical inlet (5 cm diameter, 14 cm long) attached to the main detection block resulting in a total distance of approximately 20 cm from the nozzle to the detection volume (Fig.…”

Section: Detection Of Oh Radicalsmentioning

confidence: 99%

See 3 more Smart Citations

Measurements of a potential interference with laser-induced fluorescence measurements of ambient OH from the ozonolysis of biogenic alkenes

Rickly

Stevens

2018

Atmos. Meas. Tech.

View full text Add to dashboard Cite

Abstract. Reactions of the hydroxyl radical (OH) play a central role in the chemistry of the atmosphere, and measurements of its concentration can provide a rigorous test of our understanding of atmospheric oxidation. Several recent studies have shown large discrepancies between measured and modeled OH concentrations in forested areas impacted by emissions of biogenic volatile organic compounds (BVOCs), where modeled concentrations were significantly lower than measurements. A potential reason for some of these discrepancies involves interferences associated with the measurement of OH using the laser-induced fluorescencefluorescence assay by gas expansion (LIF-FAGE) technique in these environments. In this study, a turbulent flow reactor operating at atmospheric pressure was coupled to a LIF-FAGE cell and the OH signal produced from the ozonolysis of α-pinene, β-pinene, ocimene, isoprene, and 2-methyl-3-buten-2-ol (MBO) was measured. To distinguish between OH produced from the ozonolysis reactions and any OH artifact produced inside the LIF-FAGE cell, an external chemical scrubbing technique was used, allowing for the direct measurement of any interference. An interference under high ozone (between 2 × 10 13 and 10 × 10 13 cm −3 ) and BVOC concentrations (between approximately 0.1 × 10 12 and 40 × 10 12 cm −3 ) was observed that was not laser generated and was independent of the ozonolysis reaction time. For the ozonolysis of α-and β-pinene, the observed interference accounted for approximately 40 % of the total OH signal, while for the ozonolysis of ocimene the observed interference accounted for approximately 70 % of the total OH signal. Addition of acetic acid to the reactor eliminated the interference, suggesting that the source of the interference in these experiments involved the decomposition of stabilized Criegee intermediates (SCIs) inside the FAGE detection cell. Extrapolation of these measurements to ambient concentrations suggests that these interferences should be below the detection limit of the instrument.

show abstract

Section: Interference From Criegee Intermediate Decomposition On Lif-mentioning

confidence: 46%

Section: Detection Of Oh Radicalsmentioning

confidence: 99%

Section: Detection Of Oh Radicalsmentioning

confidence: 99%

Section: Detection Of Oh Radicalsmentioning

confidence: 99%

See 2 more Smart Citations

Measurements of a potential interference with laser-induced fluorescence measurements of ambient OH from the ozonolysis of biogenic alkenes

Rickly

Stevens

2018

Atmos. Meas. Tech.

View full text Add to dashboard Cite

show abstract

“…Another class of instruments applies laser-induced fluorescence (LIF) for measurement of OH and HO 2 (Hard et al, 1984;Hofzumahaus and Holland, 1993;Stevens et al, 1994;Brune et al, 1995;Kanaya et al, 2001;Creasey et al, 2003;Dusanter et al, 2008;Butler et al, 2008). These instruments sample ambient air by expansion into a low pressure volume, where OH is detected spectroscopically by laser excited fluorescence at 308 nm.…”

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.

View full text Add to dashboard Cite

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.

show abstract

Measurements of hydroxyl and hydroperoxy radicals during CalNex‐LA: Model comparisons and radical budgets

et al. 2016

Self Cite

View full text Add to dashboard Cite

Measurements of hydroxyl (OH) and hydroperoxy (HO2*) radical concentrations were made at the Pasadena ground site during the CalNex‐LA 2010 campaign using the laser‐induced fluorescence‐fluorescence assay by gas expansion technique. The measured concentrations of OH and HO2* exhibited a distinct weekend effect, with higher radical concentrations observed on the weekends corresponding to lower levels of nitrogen oxides (NOx). The radical measurements were compared to results from a zero‐dimensional model using the Regional Atmospheric Chemical Mechanism‐2 constrained by NOx and other measured trace gases. The chemical model overpredicted measured OH concentrations during the weekends by a factor of approximately 1.4 ± 0.3 (1σ), but the agreement was better during the weekdays (ratio of 1.0 ± 0.2). Model predicted HO2* concentrations underpredicted by a factor of 1.3 ± 0.2 on the weekends, while measured weekday concentrations were underpredicted by a factor of 3.0 ± 0.5. However, increasing the modeled OH reactivity to match the measured total OH reactivity improved the overall agreement for both OH and HO2* on all days. A radical budget analysis suggests that photolysis of carbonyls and formaldehyde together accounted for approximately 40% of radical initiation with photolysis of nitrous acid accounting for 30% at the measurement height and ozone photolysis contributing less than 20%. An analysis of the ozone production sensitivity reveals that during the week, ozone production was limited by volatile organic compounds throughout the day during the campaign but NOx limited during the afternoon on the weekends.

show abstract

Technical note: Measuring tropospheric OH and HO<sub>2</sub> by laser-induced fluorescence at low pressure. A comparison of calibration techniques

Cited by 72 publications

References 61 publications

Measurements of a potential interference with laser-induced fluorescence measurements of ambient OH from the ozonolysis of biogenic alkenes

Measurements of a potential interference with laser-induced fluorescence measurements of ambient OH from the ozonolysis of biogenic alkenes

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

Measurements of hydroxyl and hydroperoxy radicals during CalNex‐LA: Model comparisons and radical budgets

Contact Info

Product

Resources

About