One major concern, amongst others, is that the chemicals could reach the groundwater. One commonly used method is to drill a probe tube into the ground and to pump up the so-called pore gas. Pore gas is the air contained in the ground. By measuring these gas emissions, it is possible to monitor how much pollution is being removed from the soil per unit of time. One type of chemicals that has been widely used, amongst others in laundries and companies manufacturing metal materials, are the so-called chlorinated solvents.
Stability is particularly important when performing pore gas measurements.
The measuring equipment is often placed in remote areas for weeks or even months, performing continuous measurements of pore gas concentrations for the duration of the clean up.