Grantee Research Project Results

Inflow, Chemistry and Deposition of Mercury to the West Coast of the United States

EPA Grant Number: R829797
Title: Inflow, Chemistry and Deposition of Mercury to the West Coast of the United States
Investigators: Jaffe, Daniel , Prestbo, Eric
Institution: University of Washington
EPA Project Officer: Chung, Serena
Project Period: June 1, 2002 through June 1, 2005
Project Amount: $756,774
RFA: Mercury: Transport, Transportation, and Fate in the Atmosphere (2001) RFA Text | Recipients Lists
Research Category: Heavy Metal Contamination of Soil/Water , Air Quality and Air Toxics , Safer Chemicals , Air

Objective:

The focus of this work is to better understand the role of global sources on Hg deposition in the United States. Previously we have shown that industrial emissions in Asia can be transported to the U.S. in 5-10 days. To investigate the significance of global mercury sources on the U.S., we will make observations of Hg⁰, Reactive gaseous mercury (RGM) and particulate (PHg) to address the following questions:

What is the contribution of Asian Hg sources to concentrations and deposition in the U.S.? During which seasons is the transport strongest?
What is the role of marine boundary layer processing on the Hg cycle? How is this processing different in the free troposphere?
What is the flux of Hg⁰, PHg and RGM into the United States from external sources and how does the mercury speciation profile change with changing air mass source region?
What is the chemical speciation of mercury in rain as air arrives to the United States and how does this change with changing air mass type and chemistry?
Are current atmospheric models accurately predicting mercury fluxes, air speciation and cloud water chemistry at the in-flow boundary to their model domain?

Approach:

We will measure Hg⁰, PHg and RGM at a coastal site on the Northwest tip of Washington state, the Cheeka Peak Observatory. This is one of the cleanest background air monitoring sites in the continental U.S. In addition we will measure these compounds in the vertical domain using a small aircraft that is available for this purpose. Our past work has shown that we can identify numerous industrial pollutants arriving to the west coast of the U.S. from sources in Asia. In this project we will extend this work to consider elemental and reactive forms of mercury. In addition we will examine the deposition of Hg by measuring the concentration and speciation in rainwater collected at the Cheeka Peak location.

Expected Results:

This project will help determine the degree which global sources contribute to mercury deposition in the U.S. This work will be the first ever to focus on this topic. From our data, it should be possible to quantify the flux of mercury into the U.S. from global sources and the importance of those sources on deposition in the U.S.

Publications and Presentations:

Publications have been submitted on this project: View all 34 publications for this project

Journal Articles:

Journal Articles have been submitted on this project: View all 7 journal articles for this project

Supplemental Keywords:

Scientific Discipline, Water, Environmental Chemistry, Ecology and Ecosystems, Mercury, fate and transport, mercury measurement, mercury formation, chemical speciation, marine boundary layer, formation, mercury detection, West Coast

Relevant Websites:

More information is available at: http://faculty.washington.edu/djaffe Exit
In addition, we may post preliminary data to this website once data collection begins.

Progress and Final Reports:

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.