Elemental mercury vapour in air: the origins and validation of the ‘Dumarey equation’ describing the mass concentration at saturation

Dumarey, R.; Brown, Richard; Corns, Warren T.; Brown, Andrew S.; Stockwell, Peter

doi:10.1007/s00769-010-0645-1

Cited by 67 publications

(62 citation statements)

References 16 publications

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“…The Tekran output c Hg 0 was given for 0uC and recalculated for the temperature measured in the upper chamber. The saturation concentration of Hg 0 (c sat Hg 0 ) in the bottom chamber was calculated from the water bath temperature T, in Kelvin, by application of the recently confirmed Dumarey equation (Dumarey et al 2010):…”

Section: Methodsmentioning

confidence: 99%

Water—air gas exchange of elemental mercury: An experimentally determined mercury diffusion coefficient for Hg⁰ water—air flux calculations

Kuss

2014

Limnology & Oceanography

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The evasion of elemental mercury (Hg 0 ) from water surfaces is a key process in biogeochemical mercury cycling. Knowledge of the Hg 0 diffusion coefficient (D Hg 0 ) in water is essential for Hg 0 water-air flux calculations, but no measured value has been available. In this study, D Hg 0 was measured in pure water and in water of oceanic salinity within an environmental temperature range between 5uC and 30uC. A diffusion cell was constructed consisting of two chambers separated by an aqueous gel membrane allowing molecular diffusion only. The corresponding parameterizations were developed on the basis of the Eyring equation, which defines an activation energy (E a ) for the diffusion process. The temperature dependences of D Hg 0 (in cm 2 s 21 ) for freshwater,0~0 :0335e { 18:63 kJ mol {1 ð Þ =RT , and for seawater, D sea Hg 0~0 :0011e { 11:06 kJ mol {1 ð Þ =RT , with R the gas constantand T the temperature in Kelvin, were thus obtained with an error of 615%. Whereas the measured D fresh Hg 0 was in good agreement with the theoretical proposals of a molecular dynamics (MD) simulation, D sea Hg 0 was clearly lower, probably because of the unaccounted effect of the polarization of mercury atoms in the salt solution, which hampers diffusion. In geochemistry applications, use of the newly determined D sea Hg 0 instead of the D Hg 0 from MD simulations would have differential effects on determinations of mercury emissions from the world's oceans. The effect on the tropical ocean would be the largest, decreasing the Hg 0 water-air flux estimate by 20%. Toward higher latitudes (,50u), the calculated emission would drop by about 10%. On the basis of a recent large data set, the estimated amount of mercury released by the Atlantic Ocean would decrease by approximately 17%.

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Section: Methodsmentioning

confidence: 99%

Water—air gas exchange of elemental mercury: An experimentally determined mercury diffusion coefficient for Hg⁰ water—air flux calculations

Kuss

2014

Limnology & Oceanography

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“…Consequently, our mass concentration measurements of Hg 0 are traceable to the accuracy at which Hg 0 vapor pressure can be gauged. For this purpose, we deployed the commonly used so-called Dumarey equation (Dumarey et al, 1985(Dumarey et al, , 2010. The performance of the (A-B) pair of gold cartridges in each of the 2537Bs was evaluated prior to each campaign.…”

Section: Calibration Detection Limit and Uncertainty In The Concentrmentioning

confidence: 99%

Mercury vapor air–surface exchange measured by collocated micrometeorological and enclosure methods – Part II: Bias and uncertainty analysis

et al. 2015

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Abstract. Dynamic flux chambers (DFCs) and micrometeorological (MM) methods are extensively deployed for gauging air-surface Hg 0 gas exchange. However, a systematic evaluation of the precision of the contemporary Hg 0 flux quantification methods is not available. In this study, the uncertainty in Hg 0 flux measured by the relaxed eddy accumulation (REA) method, the aerodynamic gradient method (AGM), the modified Bowen ratio (MBR) method, as well as DFC of traditional (TDFC) and novel (NDFC) designs, are assessed using a robust data set from two field intercomparison campaigns.The absolute precision in Hg 0 concentration difference ( C) measurements is estimated at 0.064 ng m −3 for the gradient-based MBR and AGM systems. For the REA system, the parameter is Hg 0 concentration (C) dependent at 0.069 + 0.022C. During the campaigns, 57 and 62 % of the individual vertical gradient measurements are found to be significantly different from 0, while for the REA technique, the percentage of significant observations is lower. For the chambers, non-significant fluxes are confined to a few nighttime periods with varying ambient Hg 0 concentrations. Relative bias for DFC-derived fluxes is estimated to be ∼ ±10, and ∼ 85 % of the flux bias is within ±2 ng m −2 h −1 in absolute terms. The DFC flux bias follows a diurnal cycle, which is largely affected by the forced temperature and irradiation bias in the chambers. Due to contrasting prevailing micrometeorological conditions, the relative uncertainty (median) in turbulent exchange parameters differs by nearly a factor of 2 between the campaigns, while that in C measurement is fairly consistent. The estimated flux uncertainties for the triad of MM techniques are 16-27, 12-23 and 19-31 % (interquartile range) for the AGM, MBR and REA methods, respectively. This study indicates that flux-gradient-based techniques (MBR and AGM) are preferable to REA in quantifying Hg 0 flux over ecosystems with low vegetation height. A limitation of all Hg 0 flux measurement systems investigated is their inability to obtain synchronous samples for the calculation of C. This reduces the precision of flux quantification, particularly in the MM systems under non-stationarity of ambient Hg 0 concentration. For future applications, it is recommended to accomplish C derivation from simultaneous collected samples.

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“…The transfer syringe was at room temperature and the saturated gas was withdrawn from the vial and directly injected slightly upstream of the fluorescence cell. The GEM concentration was calculated assuming saturation, correcting for the temperature difference between the syringe and the vial, and using the temperature dependence of the vapor pressure given by the Dumarey equation [20].…”

Section: Calibration Of Absolute Hg° Concentrationmentioning

confidence: 99%

Programmable Thermal Dissociation of Reactive Gaseous Mercury, a Potential Approach to Chemical Speciation: Results from a Field Study

et al. 2014

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Based on "Tatum Ernest, C.; Donohoue, D.; Bauer, D.; Ter Schure, A.; Hynes, A.J. Programmable thermal dissociation of reactive gaseous mercury-A potential approach to chemical speciation: Results from a field study. Atmos. Chem. Phys. Discuss. 2012, 12, 33291-33322 ). RGM was collected on denuders and analyzed using PTD. The technique was tested in a field campaign at a coal-fired power plant in Pensacola, Florida. Stack gas samples were collected from ducts located after the electrostatic precipitator and prior to entering the stack. An airship was used to sample from the stack plume, downwind of the stack exit. The PTD profiles from these samples were compared with PTD profiles of HgCl 2 . Comparison of stack and in-plume samples suggest that the chemical speciation are the same and that it is possible OPEN ACCESSAtmosphere 2014, 5 576 to track a specific chemical form of RGM from the stack and follow its evolution in the stack plume. Comparison of the measured plume RGM with the amount calculated from in-stack measurements and the measured plume dilution suggest that the stack and plume RGM concentrations are consistent with dilution. The PTD profiles of the stack and plume samples are consistent with HgCl 2 being the chemical form of the sampled RGM. Comparison with literature PTD profiles of reference mercury compounds suggests no other likely candidates for the speciation of RGM.

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Elemental mercury vapour in air: the origins and validation of the ‘Dumarey equation’ describing the mass concentration at saturation

Cited by 67 publications

References 16 publications

Water—air gas exchange of elemental mercury: An experimentally determined mercury diffusion coefficient for Hg⁰ water—air flux calculations

Water—air gas exchange of elemental mercury: An experimentally determined mercury diffusion coefficient for Hg⁰ water—air flux calculations

Mercury vapor air–surface exchange measured by collocated micrometeorological and enclosure methods – Part II: Bias and uncertainty analysis

Programmable Thermal Dissociation of Reactive Gaseous Mercury, a Potential Approach to Chemical Speciation: Results from a Field Study

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Elemental mercury vapour in air: the origins and validation of the ‘Dumarey equation’ describing the mass concentration at saturation

Cited by 67 publications

References 16 publications

Water—air gas exchange of elemental mercury: An experimentally determined mercury diffusion coefficient for Hg0 water—air flux calculations

Water—air gas exchange of elemental mercury: An experimentally determined mercury diffusion coefficient for Hg0 water—air flux calculations

Mercury vapor air–surface exchange measured by collocated micrometeorological and enclosure methods – Part II: Bias and uncertainty analysis

Programmable Thermal Dissociation of Reactive Gaseous Mercury, a Potential Approach to Chemical Speciation: Results from a Field Study

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Water—air gas exchange of elemental mercury: An experimentally determined mercury diffusion coefficient for Hg⁰ water—air flux calculations

Water—air gas exchange of elemental mercury: An experimentally determined mercury diffusion coefficient for Hg⁰ water—air flux calculations