A very small electronic sensor developed by engineers in the ETH in Zurich can effectively help rescuers searching for people trapped under avalanches or under collapsed housing following an earthquake. In these situations dogs are often used due to their very sensitive noses, but sometimes they are not immediately available and, in any case, need to take breaks and be fed. The electronic devices currently available to rescuers (mini video cameras and probes with highly sensitive microphones) in certain cases are also unable to identify entrapped bodies in time and – in even more delicate circumstances – cannot tell if the victims of collapsed buildings and avalanches are still alive.

The device made in Zurich by the team led by Sotiris Pratsinis, Professor of Process Engineering, on the other hand is capable of detecting even the tiniest of traces of the main gases emitted by human beings, through breathing or through the skin, i.e. ammonia, isoprene and carbon dioxide, as well as measuring humidity – variations in which can signal the presence of a person that is still alive.

The new electronic sensor is about the same size as a computer chip (an area of a just few square millimetres) and is the smallest device of this kind ever made. As the researchers write in the journal Analytical Chemistry, the device has successfully passed a series of tests conducted on breath and skin emissions in different circumstances, showing that its sensitivity and specificity are very high.

This new tool, which costs little, can be inserted in probes already used by rescuers, as well as in drones that fly a few decimeters above the areas in which snow, or debris, have buried people.