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DEVELOPMENT, EVALUATION AND APPLICATION OF AN AUTOMATED EVENT PRECIPITATION SAMPLER FOR NETWORK OPERATION
Citation:
KEELER, G. J., E. CHRISTIANSON, J. BARRES, J. T. DVONCH, F. MARSIK, AND M. S. LANDIS. DEVELOPMENT, EVALUATION AND APPLICATION OF AN AUTOMATED EVENT PRECIPITATION SAMPLER FOR NETWORK OPERATION. Presented at Annual NADP Meeting, Norfolk, VA, October 24 - 26, 2006.
Impact/Purpose:
The overall research objective of this task is to improve our understanding of the emission, transport, transformation, and deposition of atmospheric mercury. Information garnered from this research is used to improve and evaluate EPA deterministic models that are used to investigate the (i) relative impact to local, regional, and global sources to atmospheric mercury deposition, and (ii) benefits of various emission reduction scenarios.
Specifically, individual research project objectives are listed below:
(1) Evaluate the ability of speciated mercury (Hg0, Hg2+, HgP) measurements to aid source apportionment models in identifying anthropogenic source contributions to atmospheric mercury deposition
(2) Elucidate the contribution of coal combustion sources to observed mercury wet deposition in the Ohio River Valley
(3) Obtain atmospheric profiles (200 - 12,000 ft) of speciated ambient mercury off the south Florida Coast
- Evaluate the role of long range transport of RGM to Florida in the marine free troposphere.
- Identify any vertical mercury gradients that might indicate the presence of rapid mercury chemistry in air or in cloud water.
(4) Conduct research at Mauna Loa Observatory to elucidate elemental mercury oxidation in the remote marine free troposphere.
(5) Conduct laboratory kinetics experiments to determine the rate constants of elemental mercury oxidation to gaseous inorganic divalent mercury species from atmospheric halide species (e.g. BrO, ClO).
Description:
In 1993, the University of Michigan Air Quality Laboratory (UMAQL) designed a new wet-only precipitation collection system that was utilized in the Lake Michigan Loading Study. The collection system was designed to collect discrete mercury and trace element samples on an event basis. Results showed that with proper preparation and ultra-clean collection techniques, wet-only precipitation collection utilizing the UMAQL modified MIC-B collector can provide virtually contamination-free mercury and trace element samples. Subsequent application of this collector has led to several source-receptor studies that utilized the event precipitation chemistry data to investigate the sources and pathways for atmospheric contaminants entering sensitive ecosystems.