Synopsis: A number of monitoring studies have provided estimated rates of mercury wet deposition to sensitive ecosystems within the Great Lakes and beyond. In contrast, the ability to place bounds on the rates of mercury dry deposition has been hampered by the relative lack of direct measurements of this process. Recently, a number of researchers (including the proposal PI, with support from the Michigan Great Lakes Protection Fund and the State of Florida ) have performed measurements of mercury dry deposition using a variety of direct and indirect measurement techniques (e.g., surrogate surfaces, micrometeorological flux-gradient). While these studies have provided important information regarding the potential rates of atmospheric mercury dry deposition to the surface, little is known about the comparability of the results utilizing these different mercury dry deposition techniques and/or the uncertainties associated with the individual approaches. To address the aforementioned uncertainties, we propose to host a joint Mercury Dry Deposition Measurement Intercomparison and Workshop during August 2008, the specific objectives of which include: (a) the evaluation of the capabilities of a number of unique approaches used in the quantification of mercury dry deposition, (b) the quantification of the variability between mercury dry deposition estimates resulting from the application of these unique approaches, (c) the presentation of previous research results pertaining to the measurement of mercury dry deposition by workshop participants, (d) the identification of mercury dry deposition measurement research needs and opportunities for collaboration between scientists and (e) the opportunity for interaction between scientists in the field of mercury dry deposition measurement, federal/state/local policymakers and private industry representatives.

Chemicals Studied: Mercury

Geographic Areas: N/A

Project Duration: 2 years

Potential Results and Implications: This project will provide an open assessment of the state-of-the science of mercury dry deposition measurement. The assessment will allow federal, state and local policymakers to better understand the significance of the results of previous and future mercury dry deposition studies, allowing these policymakers to make more informed decisions with respect to potential emission reduction policies. The successful completion of this project will allow researchers to develop an improved suite of tools with which to: (1) quantify mercury dry depositional loading to a wide range of ecosystems, (2) provide improved input into total maximum daily loading modeling activities, (3) validate regional/global mercury transport, transformation and fate models, (4) monitor the impacts of mercury emission reduction activities and (5) better understand the processes controlling the rates of mercury dry deposition. The ultimate benefits will be improved human and ecosystem health and welfare.

Project Contact:
Dr. Frank J. Marsik
University of Michigan Air Quality Lab
Dept. of Atmospheric, Oceanic and Space Sciences
2455 Hayward Avenue, Ann Arbor, Michigan 48109
Phone: (734) 763-5369
Email: marsik@umich.edu