Portable device can ‘sniff out’ humans trapped after quakes

Scientists have developed a light and portable sensor that can detect even the faintest signs of life, and could be used to rescue people trapped in rubble after an earthquake or bombing.

The first step after buildings collapse due to a disaster is to rescue people who could be trapped in the rubble. However, finding entrapped humans among the ruins can be challenging.

Light and affordable

Scientists from ETH Zurich in Switzerland and University of Innsbruck in Austria have developed an inexpensive sensor that is light and portable enough for first responders to hold in their hands or for drones to carry on a search for survivors.

Current approaches include the use of human-sniffing dogs and acoustic probes that can detect cries for help. However, these methods have drawbacks, such as the limited availability of canines and the silence of unconscious victims.

Devices that detect a human chemical signature, which includes molecules that are exhaled or that waft off the skin, are promising. These devices were too bulky and expensive for wide implementation, and could miss signals present at low concentrations, researchers said. So the researchers wanted to develop an affordable, compact sensor array to detect even the most faint signs of life, according to a study published in Analytical Chemistry.

The researchers built the 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.

They also included two commercially available sensors for detecting humidity and CO2. In a human entrapment simulation, the sensors detected tiny amounts of these chemicals, at levels unprecedented for portable detectors — down to three parts per billion.