There are lots of calamities which people face around the world. During earthquake, people are often required to run in an open place, or to hide beneath a table, in order to protect themselves from being crushed due to the falling ceilings. Some people get trapped in the ruins of a collapsed buildings. Some die and some live. To locate them once the earthquake is over, is difficult. Rescuers use electronic devices with cameras and microphones. This device helps to find people stucked beneath the ruins who are not dead. The main disadvantage of the device is that we can’t find people who are stucked dead beneath the ruins. They also use trained rescue dogs inorder to find them.
Trained rescue dogs use their noses to find the smells emitted by people. 
Figure 1- Earthquake destructions
A latest research by ETH scientists have created a sensor that helps to find people beneath the ruins without the help of cameras and microphones. This group of researchers at ETH Zurich is led by Sotiris Pratsinis, Professor of Process Engineering. This sensor detects the bodies of stucked people by sensing the gas inputs provided by the human body.
We normally emit metabolic products such as acetone, ammonia, and isoprene in low concentrations via our breath or skin. Isoprene and acetone are the metabolic products that we normally emit through our breath. Ammonia on the other hand is emitted through our skin. 
Figure 2- Original chromatogram of a breath sample
Humans also emit carbon dioxide through breathing and there is a presence of moisture in it. The scientists now combined this sensitive sensor along with carbon dioxide and moisture sensors. 
Figure3 – Carbon dioxide sensors
This is because the human emits more carbon dioxide than metabolic products through breathing. If the person is stucked and the sensor is near to him, the sensor will detect some of the gases, and if the carbon dioxide is coming through another source, then the other sensors will detect inorder to avoid false detections. The combination of these sensors is quite useful and will give reliable indications of stucked people.
The material size of the sensor is merely a size of computer chip.
So, it will be helpful to find people who are stucked in inaccessible areas beneath the ruins. Thus, this sensor is suitable for attaching it to a drone and robot as well.
The ETH scientists will be using this sensor practically if such a situation of earthquake will arise in the near future.
They are finding new investors inorder to develop the processing of making this sensor on an industrial basis. They are also currently finding new applications which can employ this sensitive sensor for the greater good of the society. Combining this sensor with other chemical sensors can be very beneficial.