Measurement of OH reactivity by laser flash photolysis coupled with
laser-induced fluorescence spectroscopy

Stone, Daniel; Whalley, Lisa K.; Ingham, T.; Edwards, P. M.; Cryer, D. R.; Brumby, Charlotte A.; Seakins, Paul W.; Heard, Dwayne E.

doi:10.5194/amt-9-2827-2016

Cited by 30 publications

(39 citation statements)

References 53 publications

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“…For NO mixing ratios of less than 0.3 ppbv, OH destruction was nearly twice as large as the OH production, whereas pro- duction and destruction was balanced for NO mixing ratios higher than 1 ppbv. The result of the budget analysis is consistent with the finding by Tan et al (2017) that model calculations underpredict OH by up to a factor of 2 at NO mixing ratios of less than 0.3 ppbv but describe HO 2 and k OH correctly under these conditions at the Wangdu site. The good description of HO 2 and k OH means that the major known OH source (the reaction of HO 2 and NO) and the total OH loss rate are represented well by the model.…”

Section: Experimental Oh Budgetsupporting

confidence: 87%

“…A large number of instruments characterized meteorological conditions, trace gas concentrations and aerosol properties. The measurements used for the OH reactivity analysis are listed in Table 1. OH and HO 2 radical concentrations were measured by a newly built instrument of Peking University (PKU) applying laser-induced fluorescence (PKU-LIF) (Tan et al, 2017). This instrument detects OH fluorescence by time-delayed single photon counting after excitation by short laser pulses at 308 nm in a low-pressure cell (Holland et al, 2003;Fuchs et al, 2011).…”

Section: Instrumentationmentioning

confidence: 99%

“…Nitrous acid (HONO) concentrations were simultaneously measured by several instruments applying different measurement techniques (Tan et al, 2017). Custom-built instruments from FZJ (Forschungszentrum Jülich) and from PKU (Liu et al, 2016) utilized long-path absorption photometry (LOPAP).…”

Section: Instrumentationmentioning

confidence: 99%

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Fuchs¹

2016

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In 2014, a large, comprehensive field campaign was conducted in the densely populated North China Plain. The measurement site was located in a botanic garden close to the small town Wangdu, without major industry but influenced by regional transportation of air pollution. The loss rate coefficient of atmospheric hydroxyl radicals (OH) was quantified by direct measurements of the OH reactivity. Values ranged between 10 and 20 s −1 for most of the daytime. Highest values were reached in the late night with maximum values of around 40 s −1 . OH reactants mainly originated from anthropogenic activities as indicated (1) by a good correlation between measured OH reactivity and carbon monoxide (linear correlation coefficient R 2 = 0.33) and (2) by a high contribution of nitrogen oxide species to the OH reactivity (up to 30 % in the morning). Total OH reactivity was measured by a laser flash photolysis-laser-induced fluorescence instrument (LP-LIF). Measured values can be explained well by measured trace gas concentrations includ-ing organic compounds, oxygenated organic compounds, CO and nitrogen oxides. Significant, unexplained OH reactivity was only observed during nights, when biomass burning of agricultural waste occurred on surrounding fields. OH reactivity measurements also allow investigating the chemical OH budget. During this campaign, the OH destruction rate calculated from measured OH reactivity and measured OH concentration was balanced by the sum of OH production from ozone and nitrous acid photolysis and OH regeneration from hydroperoxy radicals within the uncertainty of measurements. However, a tendency for higher OH destruction compared to OH production at lower concentrations of nitric oxide is also observed, consistent with previous findings in field campaigns in China.

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Section: Experimental Oh Budgetsupporting

confidence: 87%

Section: Instrumentationmentioning

confidence: 99%

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Fuchs¹

2016

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“…Fundamental data of OH molecular transitions are communicated in selected references [31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49]. Interrogations of ground-state or ground-level populations employ laser-induced fluorescence [50][51][52][53][54][55][56][57][58][59][60][61][62][63][64][65][66][67][68] with practical applications to combustion diagnosis [69][70][71][72][73][74]. However, diagnosis applications are based on extensive studies of the ultraviolet OH system [75][76][77][78][79]…”

Section: Mini-summary Of Oh Literature and Applicationsmentioning

confidence: 99%

Laser-Plasma Spectroscopy of Hydroxyl with Applications

et al. 2020

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This article discusses laser-induced laboratory-air plasma measurements and analysis of hydroxyl (OH) ultraviolet spectra. The computations of the OH spectra utilize line strength data that were developed previously and that are now communicated for the first time. The line strengths have been utilized extensively in interpretation of recorded molecular emission spectra and have been well-tested in laser-induced fluorescence applications for the purpose of temperature inferences from recorded data. Moreover, new experiments with Q-switched laser pulses illustrate occurrence of molecular recombination spectra for time delays of the order of several dozen of microseconds after plasma initiation. The OH signals occur due to the natural humidity in laboratory air. Centrifugal stretching of the Franck-Condon factors and r-centroids are included in the process of determining the line strengths that are communicated as a Supplementary File. Laser spectroscopy applications of detailed OH computations include laser-induced plasma and combustion analyses, to name but two applications. This work also includes literature references that address various diagnosis applications.

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“…A gap in the understanding of OH recycling processes was found in a field study in Nashville in 1999 , in China in 2006 , in Borneo in 2008 (Whalley et al, 2011) and in chamber experiments investigating the oxidation of isoprene by OH . Because of the close connection between oxidation of organic compounds by OH and ozone production, OH reactivity can help to calculate local ozone production rates .…”

Section: Introductionmentioning

confidence: 99%

Comparison of OH reactivity measurements in the atmospheric simulation chamber SAPHIR

Fuchs¹,

Novelli²,

Rolletter³

et al. 2017

Atmos. Meas. Tech.

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Abstract. Hydroxyl (OH) radical reactivity (k OH ) has been measured for 18 years with different measurement techniques. In order to compare the performances of instruments deployed in the field, two campaigns were conducted performing experiments in the atmospheric simulation chamber SAPHIR at Forschungszentrum Jülich in October 2015 and April 2016. Chemical conditions were chosen either to be representative of the atmosphere or to test potential limitations of instruments. All types of instruments that are currently used for atmospheric measurements were used in one of the two campaigns. The results of these campaigns demonstrate that OH reactivity can be accurately measured for a wide range of atmospherically relevant chemical conditions (e.g. water vapour, nitrogen oxides, various organic compounds) by all instruments. The precision of the measurements (limit of detection < 1 s −1 at a time resolution of 30 s to a few minutes) is higher for instruments directly detecting hydroxyl radicals, whereas the indirect comparative reactivPublished by Copernicus Publications on behalf of the European Geosciences Union. H. Fuchs et al.: OH reactivity comparison in SAPHIRity method (CRM) has a higher limit of detection of 2 s −1 at a time resolution of 10 to 15 min. The performances of the instruments were systematically tested by stepwise increasing, for example, the concentrations of carbon monoxide (CO), water vapour or nitric oxide (NO). In further experiments, mixtures of organic reactants were injected into the chamber to simulate urban and forested environments. Overall, the results show that the instruments are capable of measuring OH reactivity in the presence of CO, alkanes, alkenes and aromatic compounds. The transmission efficiency in Teflon inlet lines could have introduced systematic errors in measurements for low-volatile organic compounds in some instruments. CRM instruments exhibited a larger scatter in the data compared to the other instruments. The largest differences to reference measurements or to calculated reactivity were observed by CRM instruments in the presence of terpenes and oxygenated organic compounds (mixing ratio of OH reactants were up to 10 ppbv). In some of these experiments, only a small fraction of the reactivity is detected. The accuracy of CRM measurements is most likely limited by the corrections that need to be applied to account for known effects of, for example, deviations from pseudo first-order conditions, nitrogen oxides or water vapour on the measurement. Methods used to derive these corrections vary among the different CRM instruments. Measurements taken with a flowtube instrument combined with the direct detection of OH by chemical ionisation mass spectrometry (CIMS) show limitations in cases of high reactivity and high NO concentrations but were accurate for low reactivity (< 15 s −1 ) and low NO (< 5 ppbv) conditions.

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Measurement of OH reactivity by laser flash photolysis coupled with laser-induced fluorescence spectroscopy

Cited by 30 publications

References 53 publications

Response to review

Response to review

Laser-Plasma Spectroscopy of Hydroxyl with Applications

Comparison of OH reactivity measurements in the atmospheric simulation chamber SAPHIR

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