|Abstract Title:||Toward accurate, verified measurements of oxidized mercury|
|Presenter Name:||Seth Lyman|
|Company/Institution:||Bingham Research Center, Utah State University, Vernal, Utah, USA|
|Session:||Special Session - New developments in understanding reactive mercury concentrations and chemistry|
|Day and Session:||Thursday 28th July - Session Four|
|Start Time:||15:00 UTC|
Abstract Information :
Several robust, well-verified methods exist to measure gas-phase elemental mercury. Measurements of oxidized mercury have proven more difficult, however. Measurement challenges have arisen due to (1) reduction of oxidized to elemental mercury during preconcentration, (2) loss of oxidized mercury to surfaces, and (3) dynamic partitioning between the gas and particle phases. Commercial instrumentation for oxidized mercury has exhibited a low, variable measurement bias in every environment in which it has been robustly tested. New, promising measurement techniques are coming into common use, and most of these rely on collection of oxidized mercury on polyethersulfone cation exchange membranes. Several new calibration technologies for oxidized mercury in ambient air are also emerging. Calibrations of cation exchange membrane-based measurements have shown promising results, at least for commercially available gas-phase oxidized mercury compounds. To our knowledge, no work is currently being done to verify that differentiation between particle-phase and gas-phase oxidized mercury in ambient measurements is quantitative. This presentation will review the current state of oxidized mercury measurement and calibration technology and discuss remaining uncertainties and research needs.