Document Type
Article
Journal/Book Title
Atmosphere
Publication Date
1-6-2021
Publisher
MDPI AG
Award Number
NSF, Division of Atmospheric and Geospace Sciences (AGS) 1951513
Funder
NSF, Division of Atmospheric and Geospace Sciences (AGS)
Volume
12
Issue
1
First Page
1
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.
Last Page
18
Abstract
This review focuses on providing the history of measurement efforts to quantify and characterize the compounds of reactive mercury (RM), and the current status of measurement methods and knowledge. RM collectively represents gaseous oxidized mercury (GOM) and that bound to particles. The presence of RM was first recognized through measurement of coal-fired power plant emissions. Once discovered, researchers focused on developing methods for measuring RM in ambient air. First, tubular KCl-coated denuders were used for stack gas measurements, followed by mist chambers and annular denuders for ambient air measurements. For ~15 years, thermal desorption of an annular KCl denuder in the Tekran® speciation system was thought to be the gold standard for ambient GOM measurements. Research over the past ~10 years has shown that the KCl denuder does not collect GOM compounds with equal efficiency, and there are interferences with collection. Using a membrane-based system and an automated system—the Detector for Oxidized mercury System (DOHGS)—concentrations measured with the KCl denuder in the Tekran speciation system underestimate GOM concentrations by 1.3 to 13 times. Using nylon membranes it has been demonstrated that GOM/RM chemistry varies across space and time, and that this depends on the oxidant chemistry of the air. Future work should focus on development of better surfaces for collecting GOM/RM compounds, analytical methods to characterize GOM/RM chemistry, and high-resolution, calibrated measurement systems.
Recommended Citation
Gustin, M.S.; Dunham-Cheatham, S.M.; Huang, J.; Lindberg, S.; Lyman, S.N. Development of an Understanding of Reactive Mercury in Ambient Air: A Review. Atmosphere 2021, 12, 73. https://doi.org/10.3390/atmos12010073
