Traceable Calibration of Atmospheric Oxidized Mercury Measurements

Elgiar, Tyler R.; Lyman, Seth N.; Andron, Teodor D.; Gratz, Lynne; Hallar, A. Gannet; Horvat, Milena; Vijayakumaran Nair, Sreekanth; O’Neil, Trevor; Volkamer, Rainer; Živković, Igor

doi:10.1021/acs.est.4c02209

Cited by 3 publications

(2 citation statements)

References 67 publications

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“…The development of a field-deployable National Institute of Standards and Technology (NIST)-traceable GOM calibrator will be critical for the atmospheric Hg measurement community. NIST-traceable calibration of GOM is now possible, as demonstrated by nonthermal plasma generation of GOM (traceable to NIST 3133) . However, the field application of plasma calibration strategy comes with certain challenges, as it is currently developed as a discrete method that requires periodic calibrations during continuous GOM measurements (Table ).…”

Section: Gom Calibration Methodsmentioning

confidence: 99%

“…GOM-emitting permeation tubes (e.g., HgBr 2 and HgCl 2 ) used in available calibration systems emit some GEM (<10% of total Hg). The permeation tube emission speciation has been characterized by gas chromatography–mass spectrometry (GC-MS), but this method is not currently NIST-traceable. , Permeation tubes were recently compared to NIST-traceable GOM created using cold plasma, while the calibrator was at the Jožef Stefan Institute …”

Section: Gom Calibration Methodsmentioning

confidence: 99%

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Measurement of Atmospheric Mercury: Current Limitations and Suggestions for Paths Forward

Gustin,

Dunham-Cheatham,

Lyman

et al. 2024

Environ. Sci. Technol.

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Mercury (Hg) researchers have made progress in understanding atmospheric Hg, especially with respect to oxidized Hg (Hg II ) that can represent 2 to 20% of Hg in the atmosphere. Knowledge developed over the past ∼10 years has pointed to existing challenges with current methods for measuring atmospheric Hg concentrations and the chemical composition of Hg II compounds. Because of these challenges, atmospheric Hg experts met to discuss limitations of current methods and paths to overcome them considering ongoing research. Major conclusions included that current methods to measure gaseous oxidized and particulate-bound Hg have limitations, and new methods need to be developed to make these measurements more accurate. Developing analytical methods for measurement of Hg II chemistry is challenging. While the ultimate goal is the development of ultrasensitive methods for online detection of Hg II directly from ambient air, in the meantime, new surfaces are needed on which Hg II can be quantitatively collected and from which it can be reversibly desorbed to determine Hg II chemistry. Discussion and identification of current limitations, described here, provide a basis for paths forward. Since the atmosphere is the means by which Hg is globally distributed, accurately calibrated measurements are critical to understanding the Hg biogeochemical cycle.

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Section: Gom Calibration Methodsmentioning

confidence: 99%

Section: Gom Calibration Methodsmentioning

confidence: 99%

Measurement of Atmospheric Mercury: Current Limitations and Suggestions for Paths Forward

Gustin,

Dunham-Cheatham,

Lyman

et al. 2024

Environ. Sci. Technol.

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Elevated Tropospheric Iodine Over the Central Continental United States: Is Iodine a Major Oxidant of Atmospheric Mercury?

Lee,

Elgiar,

David

et al. 2024

Geophysical Research Letters

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Previous efforts to measure atmospheric iodine have focused on marine and coastal regions. We report the first ground‐based tropospheric iodine monoxide (IO) radical observations over the central continental United States. Throughout April 2022, IO columns above Storm Peak Laboratory, Colorado (3,220 m.a.s.l.) ranged from 0.7 ± 0.5 to 3.6 ± 0.5 × 1012 (average: 1.9 × 1012 molec cm−2). IO was consistently elevated in air masses transported from over the Pacific Ocean. The observed IO columns were up to three times higher and the range was larger than predicted by a global model, which warrants further investigation into iodine sources, sinks, ozone loss, and particle formation. IO mixing ratios increased with altitude. At the observed levels, iodine may be competitive with bromine as an oxidant of elemental mercury at cold temperatures typical of the free troposphere. Iodine‐induced mercury oxidation is missing in atmospheric models, understudied, and helps explain model underestimation of oxidized mercury measurements.

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Alternate materials for the capture and quantification of gaseous oxidized mercury in the atmosphere

Lown,

Dunham-Cheatham,

Lyman

et al. 2024

Atmos. Meas. Tech.

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Abstract. Methodologies for identifying atmospheric oxidized mercury (HgII) compounds, including particulate-bound HgII (HgII(p)) and gaseous oxidized mercury (HgII(g)), by mass spectrometry are currently under development. This method requires preconcentration of HgII for analysis due to high instrument detection limits relative to ambient HgII concentrations. The objective of this work was to identify and test materials for quantitative capture of HgII from the gas phase and to suggest potential surfaces onto which HgII can be collected, thermally desorbed, and characterized using mass spectrometry methods. From the literature, several compounds were identified as potential sorbent materials and tested in the laboratory for uptake of gaseous elemental mercury (Hg0) and HgII(g) (permeated from a HgBr2 salt source). Chitosan, α-Al2O3, and γ-Al2O3 demonstrated HgII(g) capture in ambient air laboratory tests, without sorbing Hg0 under the same conditions. When compared to cation exchange membranes (CEMs), chitosan captured a comparable quantity of HgII(g), while ≤90 % of loaded HgII(g) was recovered from α-Al2O3 and γ-Al2O3. When deployed in the field, the capture efficiency of chitosan decreased compared to CEMs, indicating that environmental conditions impacted the sorption efficiency of this material. The poor recovery of HgII from the tested materials compared to CEMs in the field indicates that further identification and exploration of alternative sorbent materials are required to advance atmospheric mercury chemistry analysis by mass spectrometry methods.

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Traceable Calibration of Atmospheric Oxidized Mercury Measurements

Cited by 3 publications

References 67 publications

Measurement of Atmospheric Mercury: Current Limitations and Suggestions for Paths Forward

Measurement of Atmospheric Mercury: Current Limitations and Suggestions for Paths Forward

Elevated Tropospheric Iodine Over the Central Continental United States: Is Iodine a Major Oxidant of Atmospheric Mercury?

Alternate materials for the capture and quantification of gaseous oxidized mercury in the atmosphere

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