Journal cover Journal topic
Atmospheric Chemistry and Physics An interactive open-access journal of the European Geosciences Union
Atmos. Chem. Phys., 17, 1689-1698, 2017
https://doi.org/10.5194/acp-17-1689-2017
© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
03 Feb 2017
Deciphering potential chemical compounds of gaseous oxidized mercury in Florida, USA
Jiaoyan Huang1, Matthieu B. Miller2, Eric Edgerton3, and Mae Sexauer Gustin2 1Institute for the Environment, University of North Carolina, Chapel Hill, 100 Europa Drive, Suite 490, Chapel Hill, NC, 27517, USA
2Department of Natural Resources and Environmental Sciences, University of Nevada-Reno,1664 N. Virginia Street, Reno, NV, 89557, USA
3Atmospheric Research & Analysis, Inc., 410 Midenhall Way, Cary, North Carolina 27513, USA
Abstract. The highest mercury (Hg) wet deposition in the United States of America (USA) occurs along the Gulf of Mexico, and in the southern and central Mississippi River Valley. Gaseous oxidized Hg (GOM) is thought to be a major contributor due to high water solubility and reactivity. Therefore, it is critical to understand concentrations, potential for wet and dry deposition, and GOM compounds present in the air. Concentrations and dry-deposition fluxes of GOM were measured and calculated for Naval Air Station Pensacola Outlying Landing Field (OLF) in Florida using data collected by a Tekran® 2537/1130/1135, the University of Nevada Reno Reactive Mercury Active System (UNRRMAS) with cation exchange and nylon membranes, and the Aerohead samplers that use cation-exchange membranes to determine dry deposition. Relationships with Tekran®-derived data must be interpreted with caution, since the GOM concentrations measured are biased low depending on the chemical compounds in air and interferences with water vapor and ozone.

Criteria air pollutants were concurrently measured. This allowed for comparison and better understanding of GOM.

In addition to other methods previously applied at OLF, use of the UNRRMAS provided a platform for determination of the chemical compounds of GOM in the air. Results from nylon membranes with thermal desorption analyses indicated seven GOM compounds in this area, including HgBr2, HgCl2, HgO, Hg–nitrogen and sulfur compounds, and two unknown compounds. This indicates that the site is influenced by different gaseous phase reactions and sources. Using back-trajectory analysis during a high-GOM event related to high CO, but average SO2, indicated air parcels moved from the free troposphere and across Arkansas, Mississippi, and Alabama at low elevation (< 300 m). This event was initially characterized by HgBr2, followed by a mixture of GOM compounds. Overall, GOM chemistry indicates oxidation reactions with local mobile source pollutants and long-range transport.

In order to develop methods to measure GOM concentrations and chemistry, and model dry-deposition processes, the actual GOM compounds need to be known, as well as their corresponding physicochemical properties, such as Henry's Law constants.


Citation: Huang, J., Miller, M. B., Edgerton, E., and Sexauer Gustin, M.: Deciphering potential chemical compounds of gaseous oxidized mercury in Florida, USA, Atmos. Chem. Phys., 17, 1689-1698, https://doi.org/10.5194/acp-17-1689-2017, 2017.
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Short summary
The highest mercury (Hg) wet deposition in USA occurs along the Gulf of Mexico. Gaseous oxidized Hg (GOM) is a major contributor due to high water solubility and reactivity. Concentration and dry deposition of GOM were determined for OLF, Florida. Results indicated at least 5 GOM compounds in this area including HgBr2, HgO, and Hg–nitrogen and –sulfur forms. GOM chemistry indicates reactions with local mobile source pollutants and long-range transport from outside of the USA.
The highest mercury (Hg) wet deposition in USA occurs along the Gulf of Mexico. Gaseous oxidized...
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