The situation was made worse when it was realized that mercury fluxes can vary rapidly over time, being dependent such factors as amount of sunlight, temperature, and moisture. The Model 2537A is capable of extremely rapid and precise measurements, making it ideal for flux monitoring. It came as a welcome relief to those working in the field and has turned out to be one of the major research applications for the analyzer. A flux chamber is basically a box with an open bottom that is placed over the surface to be measured. The box has an inlet and an outlet.
Ambient air is drawn into the chamber by a pump.
If the exit is higher than ambient, mercury is being emitted by the soil. If it is less, then mercury is being absorbed into the surface. If you know the flow rate through the chamber and the surface area covered by it, the flux can be calculated. Flux chamber techniques are very sensitive and can measure very small positive or negative fluxes. They have a defined footprint so the region being measured is always known.