Mobile Atmospheric Mercury Laboratory Capabilities
A view of the air intake with access doors open for the mercury speciation unit of the USGS
Mobile Mercury Laboratory. The intake "strips" particulate and reactive gaseous mercury species from air, allowing gaseous elemental mercury (Hg0
) to pass to a detector. After a two-hour accumulation period, particulate and reactive gaseous mercury (Hg+2,+1
) are thermally desorbed and passed to the detector for analysis.
U.S. Geological Survey (USGS) scientists have developed a mobile atmospheric mercury laboratory capable of rapidly measuring the speciation and concentration of mercury in air, as well as relevant air quality and meteorological parameters. The mobile laboratory is capable of
- Real-time measurements of mercury speciation — elemental mercury (Hg0), gaseous ionic mercury (Hg+2,+1), and particulate mercury — in air.
- Real-time measurements of air-quality parameters — ozone, sulfur oxides (SOx), nitrous oxides (NOx), elemental carbon, organic carbon, and particulate matter.
- Making continuous measurements for all constituents.
- Recording meteorological data—wind speed and direction, temperature, barometric pressure, precipitation, and incident sunlight intensity.
- Unattended wet-deposition sampling—enables the quantification of mercury in wet deposition (measured directly) and dry deposition (extrapolated estimation).
- Analysis of mercury aerosol (gaseous suspension of fine solid or liquid particles) concentrations (>pm 2.5 microns).
The combined multimedia data collected by the mobile laboratory enables scientists to examine the relative importance of local versus regional versus global mercury contributions at a site. This is done by comparing wind direction, air quality data, concentrations of the three primary forms of mercury in air (gaseous elemental, particulate, and reactive gaseous mercury), and the location of known mercury sources. At present (2005), few studies have undertaken detailed examination of the relationship between possible sources of mercury (local, regional, and global) and places where mercury is deposited (lakes, wetlands, …). This relationship is important to evaluate in order to assess whether corrective actions on a local, regional, or global level would achieve improved environmental conditions at a given location.
Related Science Features
More Science Features