Flux monitoring is an emissions measurement method applicable to fugitive area sources such as evaporative emissions from land surfaces or from water surfaces, whereas stack sampling methods are applied to emissions from point sources. Various methods can be use to determine scalar fluxes from surfaces such as the gradient-flux method, bowen-ratio, eddy correlation, eddy accumulation and the flux chamber method, to name a few.
In routine practical applications, Airzone utilizes the chamber method whereas the other methods are typically applied for research projects. In the chamber method, emissions are captured with a flux chamber placed over a typical representative surface. The chamber is flushed with zero gas/air at known flow rates. Depending on the substances being sampled, sampling methods may vary from the use of real-time monitoring instruments to integrative methods such as charcoal tubes or thermal desorption tubes or canisters, etc.
Airzone’s experience with flux chamber monitoring dates to the 1980s when we applied flux chamber techniques to measure emissions of reduced sulfur and VOCs from ponds and other surfaces at oil sands facilities, to complement other measurement methods at point sources, to arrive at comprehensive emissions scenarios from oil sands including those from mine surfaces, pond surfaces and upgrading plants.