Diffuse Flux

Diffuse carbon dioxide fluxes have a very broad dynamic variation, ranging from fractions of one μmol/m2/s, typical of natural and agricultural soils, up to values of thousands of μmol/m2/s per second that are found in volcanoes, geothermal areas and MSW landfills.
Both the Portable FluxMeter and Long-Term monitoring device allow for detecting the entire dynamic range of the fluxes with extreme reliability.

Methane is an important greenhouse gas emitted in a diffuse form by natural and agricultural soils, mainly due to microbial activity, or in areas rich in carbon of natural origin, such as coal mines and reservoirs of hydrocarbons. Sites which are contaminated or used for storing biodegradable waste are also an important source of methane. The fluxes of methane have an extensive dynamic variation ranging from fractions of one μmol/m2/s, typical of natural and agricultural soils, up to values of thousands of μmol/m2/s that are found in volcanoes and MSW landfills.
Both the portable FluxMeter and Long-Term monitoring device allow for detecting the entire dynamic range of the fluxes with extreme reliability thanks to an IR analyser based on a multipass cell and a tunable diode laser (TDLAS) that allows for creating a fluxmeter for methane (or natural gas) which is lightweight, compact and easy to use in the field.

Hydrogen sulphide is a sulphur gas naturally present in volcanic and geothermal areas, as well as in MSW landfills and some contaminated sites. Its presence is sometimes associated with that of hydrocarbons of natural origin. The H₂S emissions are normally of minor intensity, except for a few rare exceptions and therefore their measurement requires high-sensitivity instrumentation. Both the Portable FluxMeter and Long-Term monitoring device are able to measure the H₂S fluxes with extreme reliability thanks to an analyser based on a differential electrochemical cell, the sensitivity and stability of which allow for creating instrumentation which is lightweight, compact and easy to use in the field.

The VOCs are a class of organic compounds that include amongst others, hydrocarbons, aldehydes, ethers, esters, CFCs, HCFCs, and alcohols, etc. The emissions of these compounds are mainly related to anthropogenic contamination of the soil and groundwater. Our Portable FluxMeter makes it possible to quantify the VOC emissions in a very short time, and also allows for sampling the soil gas for the speciation analyses via use of a canister or chemical traps combined with thermal desorption.

Nitrous oxide occurs in small amounts in the atmosphere, however it has recently been found to be a major scavenger of stratospheric ozone, with an impact comparable to that of the CFCs. It is estimated that 30% of the N₂O in the atmosphere is the result of human activity, chiefly agriculture (7%). With a GWP of 298 and an atmospheric concentration of 0.3 ppm it represents one of the most important GHGs. The IPNOA Mobile FluxMeter is one of the few autonomous instruments capable of performing the mapping of the N₂O emissions. The Long-term multi-chamber version is able to monitor the variations in the diffuse emissions over time in field trials.

The accumulation chamber technique is mainly used for certain gaseous species, such as CO₂, CH₄, N₂O, and VOCs. Theoretically, it can also be applied to other gaseous species as well, such as oxygen, carbon monoxide and others. Via the use of external sensors it is possible to use the Portable Fluxmeter and Long-Term Monitoring Device for measuring the δ13C on natural gas and CO₂ or the δ15N or δ18O on nitrous oxide.
Get in touch with our R&D department for more information.