Surface isolation flux chambers are used to collect air samples directly at the surfaces of solids (such as soil) and liquids (such as water, other liquids, or sludges) for chemical analysis to determine the composition and quantities of substances in the gaseous form that are released from the solid or liquid media. The purpose is to eliminate the influence of wind, which would cause turbulences and dilution of the gas layer above the medium of interest, thereby making it impossible to conduct any accurate analysis.

A flux chamber consists of a circular box that is placed on the area of interest, to isolate it from external air movement. Sweep air is then passed in a controlled manner across the surface that is isolated and the exiting air is collected for chemical analysis. From the analysis value (concentration in air), the known velocity of the sweep air and the area of the isolated surface, the release of a substance from the isolated medium can be expressed as a flux in the unit mass per surface area per time, e.g. mg/m2-min. Fluxes of selected substances can be used in mathematical dispersion models to predict air concentrations at receptor locations for the purpose of quantification of health and environmental risks.

INFOTOX has developed a flux chamber version in which concentrations of substances can be obtained from direct-read field measurements. The following substances can be quantified:

A wide variety of sorbent tubes can be used to sample for volatile substances.

Flux chambers can also be used to assess the release of odours from solids and liquids.

During exposure assessments indoor dust is often identified as a potential pathway of exposure. INFOTOX has developed a very effective and simple method for the collection of indoor dust from carpets and/or other identified indoor areas using a vacuum apparatus that collects the dust onto a pre-weighed filter.