London, Sep 12 (IANS) Molecules released by the breath, sweat and skin of human victims trapped in debris could allow portable sensors to rapidly detect their presence.
The study examined plumes of air, formed like a long feather, to create a profile of molecules that could indicate human activity in a disaster zone.
Paul Thomas, study co-author from Britain's Loughborough University, said: 'This is the first scientific study on sensing systems that could detect trapped people.
'The development of a portable detection device based on metabolites of breath, sweat and skin could hold several advantages over current techniques,' he said, the Journal of Breath Research reports.
Over five days, in six-hour intervals, a group of participants entered a simulator, designed by researchers from Loughborough University, National Technical University of Athens, University of Babe-Bolyai and University of Dortmund.
Sensors rapidly detected carbon dioxide (CO2) and ammonia (NH3) in the plumes of air that wafted through the constructed rubble, highlighting their effectiveness as potential indicators, according to a Loughborough statement.
Besides these molecules, a large number of volatile organic compounds were detected, acetone and isoprene being the most prominent potential markers.
Interestingly, there was a marked decrease in NH3 levels when the participants were asleep; a finding that researchers could not explain and will probe further.
Trapped victims release molecules from breath, skin and other bodily fluids, which can interact with building materials.
These interactions can change with conditions such as humidity, heat and wind strength and direction, making the detection process much more difficult.