A lightweight sensor can help sniff out survivors in disaster zones

Luke Dormehl
American Chemical Society

There are a number of different ways that search and rescue teams look for survivors in the aftermath of disasters, such as earthquakes or bombings. A team of researchers from Austria, Switzerland, and Cyprus may have added a powerful new technology to the toolkit, however, in the form of an inexpensive sensor which can be used to help find people trapped in rubble.

The sensor is both light and portable enough that it can be carried by first responders or easily mounted onto a drone. It could help discover survivors in the all-important period of time immediately following an incident, which could mean the difference between life and death.

“In the aftermath of an earthquake, many victims are entrapped under collapsed structures and need rapid help, because survival rates drop dramatically within the first hours,” Sotiris Pratsinis, Professor of Process Engineering at ETH Zurich in Switzerland, told Digital Trends. “Currently indispensable for urban search and rescue are dogs with their superior ability to sniff entrapped humans from their scent. However, their availability and operational time are limited and they are rather stress-sensitive. Here, we built a palm-sized and inexpensive sensor array that can detect humans by sniffing their chemical signature as well.”

The team’s diminutive device consists of five sensors in all. Two of these are commercially available sensors for detecting humidity and carbon dioxide. There are also three tailor-made sensors, able to detect the specific breath and skin-emitted chemicals acetone, ammonia or isoprene at even tiny, trace-level concentrations. This is significantly better than the current bulky, expensive sensors currently used for this task, which can miss signals if they are not present at high enough concentrations.

“[We’ve so far] tested our sensors in a human entrapment simulation,” Pratsinis continued. “Volunteers were enclosed in a gas-tight chamber to accumulate their breath and skin emissions. The sensors rapidly detected human presence by sensing tiny amounts of these chemicals, at levels unprecedented for portable detectors — down to three parts per billion. The next step is to test the sensor array in the field with first responders under conditions similar to those expected in the aftermath of a calamity.”

A paper describing the project, “Sniffing Entrapped Humans with Sensor Arrays,” was recently published in the American Chemical Society journal Analytical Chemistry.