The obvious first step after the collapse of buildings from an earthquake, bombing or other disaster is to rescue people trapped under the rubble. Doing so, however, can be quite complicated due to logistic and technological reasons.
As a contribution to solving the issues faced by rescue workers, a paper out in the American Chemical Society (ACS) journal Analytical Chemistry introduces an inexpensive, selective sensor which is light enough to be held in the palm of a hand or flown over the territory by a drone.
Given the rapidly dwindling survival rate of victims trapped under blocks of concrete and other debris, first responders currently use dogs to sniff out the scent of victims and acoustic devices capable of picking up on muffled cries for help.
Effective as they are, such methods leave much to be desired – the availability of rescue canines can be quite limited, and acoustic devices do not register victims who had been rendered unconscious.
While devices attuned to the chemical signature of humans, such as the variety of molecules which leave our bodies during normal exhalation, hold significant promise in the future, they are typically too bulky, expensive, and lack the sensitivity to pick up on the relevant compounds at low concentrations.
To remedy the situation, Sotiris E. Pratsinis of the ACS developed a palm-sized sensor array from three existing gas sensors, each tailored to detect a specific chemical emitted by breath or skin: acetone, ammonia or isoprene.
Improving the device further, Pratsinis and his team also equipped it with commercially available sensors for detecting humidity and CO2.
During tests which simulate human entrapment scenarios, the system was found to work at a snappy pace and was able to detect the aforesaid chemicals even at levels (down to three parts per billion) virtually imperceptible to pretty much all other portable detectors.
With the proof of concept work completed, the team hopes to bring the array out of the lab and into the field to make sure its functionality is not reduced under real-world conditions following the aftermath of an urban disaster.