Sensitivity of Heterogeneous Atmospheric Mercury Processes to Climate ChangeEPA Grant Number: R833375
Title: Sensitivity of Heterogeneous Atmospheric Mercury Processes to Climate Change
Investigators: Schauer, James J. , Griffin, Robert J. , Holloway, Tracey , Shafer, Martin M.
Institution: University of Wisconsin - Madison , University of New Hampshire - Main Campus
EPA Project Officer: Chung, Serena
Project Period: February 15, 2007 through February 14, 2010 (Extended to February 14, 2011)
Project Amount: $899,731
RFA: Consequences of Global Change For Air Quality (2006) RFA Text | Recipients Lists
Research Category: Global Climate Change , Climate Change , Air
The overall goal of the project is to quantify the impact of climate change on key atmospheric processes that control the fate of mercury in transport from emissions to deposition. Efforts will be directed at building on the existing scientific understanding of atmospheric mercury processes by examining the incremental impact of climate change variables on heterogeneous atmospheric mercury oxidation and depositional processes.
The goal will be realized by achieving the following objectives:
1) Quantify the sensitivity of dry deposition of elemental mercury, reactive gaseous mercury (RGM) and particulate mercury to temperature, humidity, ozone, nitrogen oxides, and sunlight intensity.
2) Quantification of sensitivity of atmospheric mercury oxidation and reduction reaction in fog and cloud water to temperature, sunlight intensity, and the composition of these atmospheric waters.
3) Investigate the oxidation of elemental mercury in the presence of the complex atmospheric reactions that produce photochemical smog and secondary organic aerosols.
4) Investigate the sensitivity of mercury deposition to climate change variables using a regional chemical transport model that will be evaluated using a year long data set of hourly speciated atmospheric mercury and event based wet deposition data.
An integrated laboratory and modeling approach is employed, building upon laboratory based low-level atmospheric mercury experiments developed under a prior EPA STAR project. Existing research expertise is applied to the following efforts:
1) Studies of mercury cycling to plant and soil surfaces at the UW-Madison Biotron controlled environment using on-line mercury instruments and mercury isotope spiking studies.
2) Laboratory studies of the chemical transformations of mercury with cloud and fog water collected using ultra-clean sampling methods along with parallel studies using artificial cloud and fog waters.
3) Smog chamber studies of mercury oxidation during controlled ozone and SOA formation studies using expertise at the University of New Hampshire.
4) Regional chemical transport modeling to study atmospheric mercury deposition sensitivity to temperature, precipitation, and atmospheric circulation patterns associated with climate change.
These efforts will result in a better understanding of impact of climate change on atmospheric mercury processes, supporting the development of strategies to control mercury deposition in the present and future. These results will help understand the broader impact of climate change.