Atmospheric mercury measurements onboard the CARIBIC passenger aircraft

Šlemr, F.; Weigelt, Alexandra; Ebinghaus, Ralf; Kock, H. H.; Bödewadt, Jan; Brenninkmeijer, C. A. M.; Rauthe-Schöch, A.; Weber, S.; Hermann, M.; Zahn, Andreas; Martinsson, B.

doi:10.5194/amt-2015-376

Cited by 7 publications

(13 citation statements)

References 3 publications

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“…The air inlet system and the mercury instrument are described in detail by Brenninkmeijer et al [] and Slemr et al []. We use a Tekran instrument, an automated dual channel, single amalgamation, cold vapor atomic fluorescence mercury analyzer.…”

Section: Methodsmentioning

confidence: 99%

“…Since April 2014 we reintegrate the raw Tekran signal using a homemade program modeled on an integration of GC peaks to remove a low bias of mercury concentrations measured with small mercury loads and to improve the precision and the detection limit of the instrument [ Slemr et al , ]. The bias in the original UT data until February 2014 was removed using a correction function derived from the original Tekran data and the reintegrated raw signal [ Slemr et al , ]. This correction also removes the bias mismatch in the original data which originated from different sampling times (5–15 min) and thus varying loads used in the measurements since May 2005.…”

Section: Methodsmentioning

confidence: 99%

“…This finding prompted us to analyze several atmospheric mercury data sets in detail, each of which encompasses more than 8 years of measurements. We use upper tropospheric data from monthly Civil Aircraft for the Regular Investigation of the atmosphere Based on an Instrumented Container (CARIBIC) flights made from 2005 until 2014 [ Slemr et al , ] and mercury concentrations measured at ground at Cape Point, South Africa, in 1995–2004 [ Slemr et al , ] and 2007–2014 [ Slemr et al , ] and at Mace Head, Ireland, in 1996–2013 [ Weigelt et al , ]. As will be discussed further below we find ENSO signatures in all these data sets.…”

Section: Introductionmentioning

confidence: 99%

“…Moreover, air and aerosol samples are collected and subsequently analyzed in the laboratory for greenhouse gases, halocarbons, hydrocarbons, and particle elemental composition. The air inlet system and the mercury instrument are described in detail by Brenninkmeijer et al [2007] and Slemr et al [2016]. We use a Tekran instrument, an automated dual channel, single amalgamation, cold vapor atomic fluorescence mercury analyzer.…”

Section: Introductionmentioning

confidence: 99%

“…This correction also removes the bias mismatch in the original data which originated from different sampling times (5-15 min) and thus varying loads used in the measurements since May 2005. Speciation experiments on board the CARIBIC container are discussed in detail by Slemr et al [2016], and they suggest that the measurements represent total mercury (TM) concentrations in air. For this paper the data from May 2005 until November 2014 were analyzed.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

El Niño–Southern Oscillation influence on tropospheric mercury concentrations

Šlemr

Brenninkmeijer

Rauthe-Schöch

et al. 2016

Geophysical Research Letters

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The El Niño–Southern Oscillation (ENSO) affects the tropospheric concentrations of many trace gases. Here we investigate the ENSO influence on mercury concentrations measured in the upper troposphere during Civil Aircraft for the Regular Investigation of the atmosphere Based on an Instrumented Container flights and at ground at Cape Point, South Africa, and Mace Head, Ireland. Mercury concentrations cross‐correlate with Southern Oscillation Index (SOI) with a lag of 8 ± 2 months. Highest mercury concentrations are always found at the most negative SOI values, i.e., 8 months after El Niño, and the amplitude of the interannual variations fluctuates between ~5 and 18%. The time lag is similar to that of CO whose interannual variations are driven largely by emissions from biomass burning (BB). The amplitude of the interannual variability of tropospheric mercury concentrations is consistent with the estimated variations in mercury emissions from BB. We thus conclude that BB is a major factor driving the interannual variation of tropospheric mercury concentrations.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

El Niño–Southern Oscillation influence on tropospheric mercury concentrations

Šlemr

Brenninkmeijer

Rauthe-Schöch

et al. 2016

Geophysical Research Letters

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Photochemistry of oxidized Hg(I) and Hg(II) species suggests missing mercury oxidation in the troposphere

Saiz‐Lopez

Travnikov

Sonke

et al. 2020

Proc. Natl. Acad. Sci. U.S.A.

105

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Mercury (Hg), a global contaminant, is emitted mainly in its elemental form Hg0 to the atmosphere where it is oxidized to reactive HgII compounds, which efficiently deposit to surface ecosystems. Therefore, the chemical cycling between the elemental and oxidized Hg forms in the atmosphere determines the scale and geographical pattern of global Hg deposition. Recent advances in the photochemistry of gas-phase oxidized HgI and HgII species postulate their photodissociation back to Hg0 as a crucial step in the atmospheric Hg redox cycle. However, the significance of these photodissociation mechanisms on atmospheric Hg chemistry, lifetime, and surface deposition remains uncertain. Here we implement a comprehensive and quantitative mechanism of the photochemical and thermal atmospheric reactions between Hg0, HgI, and HgII species in a global model and evaluate the results against atmospheric Hg observations. We find that the photochemistry of HgI and HgII leads to insufficient Hg oxidation globally. The combined efficient photoreduction of HgI and HgII to Hg0 competes with thermal oxidation of Hg0, resulting in a large model overestimation of 99% of measured Hg0 and underestimation of 51% of oxidized Hg and ∼66% of HgII wet deposition. This in turn leads to a significant increase in the calculated global atmospheric Hg lifetime of 20 mo, which is unrealistically longer than the 3–6-mo range based on observed atmospheric Hg variability. These results show that the HgI and HgII photoreduction processes largely offset the efficiency of bromine-initiated Hg0 oxidation and reveal missing Hg oxidation processes in the troposphere.

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Validating an Evaporative Calibrator for Gaseous Oxidized Mercury

Gacnik

Živković

Guevara

et al. 2021

Sensors

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Understanding atmospheric mercury chemistry is the key for explaining the biogeochemical cycle of mercury and for improving the predictive capability of computational models. Increased efforts are being made to ensure comparable Hg speciation measurements in the air through establishing metrological traceability. While traceability for elemental mercury has been recently set, this is by no means the case for gaseous oxidized mercury (GOM). Since a calibration unit suitable for traceable GOM calibrations based on evaporation of HgCl2 solution was recently developed, the purpose of our work was to extensively evaluate its performance. A highly specific and sensitive 197Hg radiotracer was used for validation over a wide range of concentrations. By comparing experimental and calculated values, we obtained recoveries for the calibration unit. The average recoveries ranged from 88.5% for 1178 ng m−3 HgCl2 gas concentration to 39.4% for 5.90 ng m−3 HgCl2 gas concentration. The losses were due to the adsorption of oxidized Hg on the inner walls of the calibrator and tubing. An adsorption isotherm was applied to estimate adsorption enthalpy (ΔHads); a ΔHads value of −12.33 kJ mol−1 was obtained, suggesting exothermal adsorption. The results of the calibrator performance evaluation suggest that a newly developed calibration unit is only suitable for concentrations of HgCl2 higher than 1 µg m−3. The concentration dependence of recoveries prevents the system from being used for calibration of instruments for ambient GOM measurements. Moreover, the previously assessed uncertainty of this unit at µg m−3 level (2.0%, k = 2) was re-evaluated by including uncertainty related to recovery and was found to be 4.1%, k = 2. Calibrator performance was also evaluated for HgBr2 gas calibration; the recoveries were much lower for HgBr2 gas than for HgCl2 gas even at a high HgBr2 gas concentration (>1 µg m−3). As HgBr2 is often used as a proxy for various atmospheric HgBr species, the suitability of the unit for such calibration must be further developed.

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Atmospheric mercury measurements onboard the CARIBIC passenger aircraft

Cited by 7 publications

References 3 publications

El Niño–Southern Oscillation influence on tropospheric mercury concentrations

El Niño–Southern Oscillation influence on tropospheric mercury concentrations

Photochemistry of oxidized Hg(I) and Hg(II) species suggests missing mercury oxidation in the troposphere

Validating an Evaporative Calibrator for Gaseous Oxidized Mercury

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