GENEVA, May 16 (Xinhua) -- Scientists in Switzerland said Wednesday they have developed a small and inexpensive piece of electronic equipment that detects people by smell and could be used in earthquake or avalanche rescue.

Researchers from the Federal Institute of Technology Zurich (ETH) said in a statement they have developed a very cheap kind of electronic rescue dog.

"Trained rescue dogs are still the best disaster workers, but they are often not immediately available and dog teams have to travel," the scientists wrote.

The device consists of a combination of sensors which can detect acetone, ammonia, isoprene, carbon dioxide and moisture, said the ETH.

These metabolic products are emitted in low concentrations via a person's breath or skin.

Individually, these substances could come from sources other than humans, such as a fire, for example, but the combination of sensors "provides the scientists with a reliable indicator of the presence of people," the ETH wrote.

The sensors have so far only been tested in laboratory conditions, in collaboration with Austrian and Cypriot scientists.

The research team, led by Sotiris Pratsinis, professor of Process Engineering at ETH Zurich, now wants to test the pin-sized device in real life conditions to test its suitability for search and rescue missions.

While electronic devices are already being used during searches after earthquakes, they rely on microphones and cameras which can only locate trapped people who can make themselves either seen or heard beneath the rubble.

The ETH scientists would like to supplement this existing equipment with their newly-developed sensors.

In addition, drones and robots could also be equipped with the device, thus allowing inaccessible and remote areas to be searched for survivors.

Further potential applications of the device could include detecting stowaways and combating human trafficking and people smuggling, said the statement.