In the aftermath of a disaster such as an earthquake, it's of the utmost importance to quickly find live victims buried under the rubble. A new device, created by a team led by ETH Zurich's Prof. Sotiris E. Pratsinis, could make doing so cheaper and easier than ever.
Currently, rescue workers search for victims mainly using sniffer dogs or acoustic probes that pick up cries for help. Sufficient numbers of the trained dogs aren't always available, however, and the probes aren't of much use in finding people who are unconscious.
There are also systems that detect chemicals given off by the human body, although they tend to be bulky and expensive, and aren't always capable of sensing low concentrations of those chemicals.
That's where the new device comes in.
Inexpensive to make and small enough to be carried in a hand or mounted on a drone, it incorporates five sensors. Three of these are each capable of detecting a specific chemical that people emit either in their breath or from their skin – these chemicals are acetone, ammonia and isoprene. The other two sensors detect humidity and CO2, both of which would also be present in the vicinity of a trapped person.
In lab tests, when people were enclosed in plethysmography chambers to simulate entrapment, the sensor array was able to detect the target chemicals at concentrations down to three parts per billion – this is reportedly unprecedented for a portable detector.
The researchers are now planning on testing the device in field conditions resembling the aftermath of a disaster.
A paper on the research was recently published in the journal Analytical Chemistry.
Source: American Chemical Society
