Radiocarbon tracer measurements of atmospheric hydroxyl radical concentrations

Campbell, M. J.; Farmer, J. Carl; Fitzner, C.A.; Henry, Miguel; Sheppard, J.C.; Hardy, Richard J.; Hopper, J. F.; Muralidhar, V.

doi:10.1007/bf00053843

Cited by 33 publications

(18 citation statements)

References 18 publications

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“…Other techniques, e.g. the salicylic acid scavenger method (Salmon et al, 2004) or the radiocarbon tracer method (Campbell et al, 1986) do not have the degree of accuracy, sensitivity and time resolution provided by LIF, CIMS, and DOAS (Schlosser et al, 2009).…”

Section: P Barmet Et Al: Oh Clock Determination By Proton Transfer mentioning

confidence: 99%

OH clock determination by proton transfer reaction mass spectrometry at an environmental chamber

et al. 2012

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Abstract. The hydroxyl free radical (OH) is the major oxidizing species in the lower atmosphere. Measuring the OH concentration is generally difficult and involves elaborate, expensive, custom-made experimental setups. Thus other more economical techniques, capable of determining OH concentrations at environmental chambers, would be valuable. This work is based on an indirect method of OH concentration measurement, by monitoring an appropriate OH tracer by proton transfer reaction mass spectrometry (PTR-MS). 3-pentanol, 3-pentanone and pinonaldehyde (PA) were used as OH tracers in α-pinene (AP) secondary organic aerosol (SOA) aging studies. In addition we tested butanold9 as a potential "universal" OH tracer and determined its reaction rate constant with OH: k butanol-d9 = 3.4(±0.88) × 10 −12 cm 3 molecule −1 s −1 . In order to make the chamber studies more comparable among each other as well as to atmospheric measurements we suggest the use of a chemical (time) dimension: the OH clock, which corresponds to the integrated OH concentration over time.

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Section: P Barmet Et Al: Oh Clock Determination By Proton Transfer mentioning

confidence: 99%

OH clock determination by proton transfer reaction mass spectrometry at an environmental chamber

et al. 2012

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“…Other techniques, e.g. the salicylic acid scavenger method (Salmon et al, 2004) or the radiocarbon tracer method (Campbell et al, 1986) do not reach the quality standards of accuracy, sensitivity and time resolution provided by LIF, CIMS, and DOAS.…”

Section: Introductionmentioning

confidence: 99%

Technical Note: Formal blind intercomparison of OH measurements: results from the international campaign HOxComp

Schlosser¹,

Brauers²,

Dorn³

et al. 2009

Atmos. Chem. Phys.

104

148

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Abstract. Hydroxyl radicals (OH) are the major oxidizing species in the troposphere. Because of their central importance, absolute measurements of their concentrations are needed to validate chemical mechanisms of atmospheric models. The extremely low and highly variable concentrations in the troposphere, however, make measurements of OH difficult. Three techniques are currently used worldwide for tropospheric observations of OH after about 30 years of technical developments: Differential Optical Laser Absorption Spectroscopy (DOAS), Laser-Induced Fluorescence Spectroscopy (LIF), and Chemical Ionisation Mass Spectrometry (CIMS). Even though many measurement campaigns with OH data were published, the question of accuracy and precision is still under discussion.Here, we report results of the first formal, blind intercomparison of these techniques. Six OH instruments (4 LIF, 1 CIMS, 1 DOAS) participated successfully in the ground-based, international HOxComp campaign carried out in Jülich, Germany, in summer 2005. Comparisons were performed for three days in ambient air (3 LIF, 1 CIMS) and for six days in the atmosphere simulation chamber SAPHIR (3 LIF, 1 DOAS). All instruments were found to measure tropospheric OH concentrations with high sensitivity and good time resolution. The pairwise correlations between different data sets were linear and yielded high correlation coefficients (r 2 =0.75−0.96). Excellent absolute agreement wasCorrespondence to: H.-P. Dorn (h.p.dorn@fz-juelich.de) observed for the instruments at the SAPHIR chamber, yielding slopes between 1.01 and 1.13 in the linear regressions. In ambient air, the slopes deviated from unity by factors of 1.06 to 1.69, which can partly be explained by the stated instrumental accuracies. In addition, sampling inhomogeneities and calibration problems have apparently contributed to the discrepancies. The absolute intercepts of the linear regressions did not exceed 0.6×10 6 cm −3 , mostly being insignificant and of minor importance for daytime observations of OH. No relevant interferences with respect to ozone, water vapour, NO x and peroxy radicals could be detected. The HOxComp campaign has demonstrated that OH can be measured reasonably well by current instruments, but also that there is still room for improvement of calibrations.

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“…Radiocarbon is by far the most important of those nuclides (Gosse & Phillips, ; Libby, ), forming at a global average rate of 2.02 atoms cm −2 s −1 (Masarik & Beer, ) mainly by the following reaction:

_{7}^{14} normalN + n - >_{6}^{14} normalC + p

where n is a neutron and p is a proton. Newly formed carbon‐14 atoms either directly form

^{14} {CO}_{2}

or, most likely, rapidly produce 14 CO molecules (equation ) which undergo further oxidation by hydroxyl radicals, forming

^{14} {CO}_{2}

(equation ) (Campbell et al, ; Pandow et al, ; Weinstock, ):

^{14} normalC + {normalO}_{2} - >^{14} CO + normalO

^{14} CO + OH - >^{14} {CO}_{2} + normalH

…”

Section: A Brief Overview On 14c Datingmentioning

confidence: 99%

The Worldwide Marine Radiocarbon Reservoir Effect: Definitions, Mechanisms, and Prospects

Alves

Macario

Ascough

et al. 2018

Reviews of Geophysics

115

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When a carbon reservoir has a lower radiocarbon content than the atmosphere, this is referred to as a reservoir effect. This is expressed as an offset between the radiocarbon ages of samples from the two reservoirs at a single point in time. The marine reservoir effect (MRE) has been a major concern in the radiocarbon community, as it introduces an additional source of error that is often difficult to accurately quantify. For this reason, researchers are often reluctant to date marine material where they have another option. The influence of this phenomenon makes the study of the MRE important for a broad range of applications. The advent of Accelerator Mass Spectrometry (AMS) has reduced sample size requirements and increased measurement precision, in turn increasing the number of studies seeking to measure marine samples. These studies rely on overcoming the influence of the MRE on marine radiocarbon dates through the worldwide quantification of the local parameter ΔR, that is, the local variation from the global average MRE. Furthermore, the strong dependence on ocean dynamics makes the MRE a useful indicator for changes in oceanic circulation, carbon exchange between reservoirs, and the fate of atmospheric CO2, all of which impact Earth's climate. This article explores data from the http://calib.qub.ac.uk/marine/ and reviews the place of natural radiocarbon in oceanic records, focusing on key questions (e.g., changes in ocean dynamics) that have been answered by MRE studies and on their application to different subjects.

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Radiocarbon tracer measurements of atmospheric hydroxyl radical concentrations

Abstract: Radiochemical techiques have many untapped applications in atmospheric chemistry, especially when great sensitivity is required. We describe the application of these techniques to the measurement of hydroxyl radical concentrations in the troposphere.

Cited by 33 publications

References 18 publications

OH clock determination by proton transfer reaction mass spectrometry at an environmental chamber

OH clock determination by proton transfer reaction mass spectrometry at an environmental chamber

Technical Note: Formal blind intercomparison of OH measurements: results from the international campaign HOxComp

The Worldwide Marine Radiocarbon Reservoir Effect: Definitions, Mechanisms, and Prospects

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