ETH Zurich scientists have developed a tiny gas sensing device that relies on olfactory tech to detect people caught in earthquakes or avalanches.
The new measuring device – unlike trained rescue dogs that need breaks every now and then – is always ready for use, asserts ETH team lead, professor Sotiris Pratsinis.
The scientists had previously developed small and extremely sensitive gas sensors for acetone, ammonia, and isoprene – all metabolic products that we emit in low concentrations via our breath or skin.
The researchers have now combined these sensors in a device with two commercial sensors for CO2 and moisture.
As shown by laboratory tests in collaboration with Austrian and Cypriot scientists, this sensor combination can be quite useful when searching for entrapped people.
The researchers used a test chamber at the University of Innsbruck’s Institute for Breath Research in Dornbirn as an entrapment simulator. Volunteers each remained in this chamber for two hours.
“The combination of sensors for various chemical compounds is important, because the individual substances could come from sources other than humans. CO2, for example, could come from either a buried person or a fire source,” explains lead author of the study, Andreas Güntner.
The researchers also showed that there are differences between the compounds emitted via our breath and skin.
“Acetone and isoprene are typical substances that we mostly breathe out. Ammonia, however, is usually emitted through the skin,” explains ETH professor Pratsinis.
In the experiments in the entrapment simulator, the participants wore a breathing mask.
In the first part of the experiment, the exhaled air was channelled directly out of the chamber; in the second part, it remained inside. This allowed the scientists to create separate breath and skin emission profiles.
The ETH scientists’ gas sensors are the size of a small computer chip and are about as sensitive as costly and bulky ion mobility spectrometers.
“Our easy-to-handle sensor combination is by far the smallest and cheapest device that is sufficiently sensitive to detect entrapped people,” asserts Pratsinis. “In a next step, we would like to test it during real conditions, to see whether it is suited for use in searches after earthquakes or avalanches.”
Content and image copyrights: ETH Zurich/Andreas Güntner