Mercury Air Monitoring

Scientists believe that a large percentage of mercury enters Wisconsin's environment through atmospheric deposition, washed out of the sky by rain or snow as "wet deposition" or deposited without the benefit of rain or snow as "dry deposition".

Atmospheric deposition is considered to be a critical step in the chain of events that make mercury available to organisms in our rivers and lakes . This step provides a logical point at which to monitor mercury levels and determine loading rates to local environments due to wet deposition. A comprehensive program to quantify mercury concentration in rain and to develop deposition loading is critical to developing a better understanding of the atmospheric deposition pathway.

Since 1994, the Department of Natural Resources, in conjunction with the Wisconsin Mercury Deposition Network (WMDN), has monitored atmospheric mercury deposition at a network of sites in Wisconsin. This work is conducted as part of the National Mercury Deposition Network [exit DNR]. The Department consists of eight monitoring stations (seven operated by the Department, and one by the Potawatomi Tribe), designed to collect information on the total (wet and dry) mercury deposition to the environment.

• Map of WMDN Sites [exit DNR]

Wisconsin Mercury Deposition Monitoring Data

• Wisconsin Mercury Deposition Network Summary Report, 1995-1997 [PDF 570K]
• Wisconsin Mercury Deposition Network Summary Report, 1998-1999 [PDF 451K]
• Mercury Deposition Network concentration and deposition maps [exit DNR]

Mercury Air Deposition Monitoring Equipment

Rural mercury monitoring site	Urban mercury monitoring site

Mercury Ambient Air Monitoring

"Ambient air monitoring" measures the concentration of specific pollutants in the air at a particular location. As part of the WDNR non-regulatory Air Toxics Monitoring effort, investigations of ambient air mercury concentrations have been conducted at several locations in Wisconsin. The results of these efforts are summarized in the reports posted below.

Note, the ambient concentrations of mercury monitored during these investigations do not exceed the air regulatory threshold levels for mercury at the time the reports were released. The ambient background concentration for mercury is about 1-2 nanograms per cubic meter, based on data collected throughout the state. The ambient air quality standard for mercury is 0.3 micrograms per cubic meter (or 300 nanograms per cubic meter) on an annual average basis, as established in chapter NR 446, Wisconsin Administrative Code.

In addition, these reports are technical in nature and include mainly the monitored ambient air concentrations of mercury, monitor site locations, and meteorology specifics during the monitoring events. No determinations or implications are made regarding any public health or wildlife effects associated with the sources that were monitored for mercury.

Ambient Monitoring Equipment

Mobile mercury monitoring trailer	Tekran ambient mercury analyzer

Mercury Air Monitoring Contacts

• Mark Allen, Air Toxics Chemist, 608.266.8049, Mark.Allen@wisconsin.gov
• Vid Grande, Air Toxics Chemist, 608.267.0812, David.Grande@wisconsin.gov
• Bruce Rodger, Air Monitoring Field Operations Team Leader, 608.266.1722, Bruce.Rodger@wisconsin.gov

Mercury and Coal-Fire Power Plants || Wisconsin's Mercury Rule And Revisions || Federal Mercury Rule || Mercury in the Environment || Other Sources of Information on Mercury || Mercury Contacts