We all know instinctively what good or bad odors are, but why is it so? What are the mechanics behind odor and its sources?

Odours are signals that guide our behavior, attracting us towards life and repelling from death and decay.

It is like a map drawn in thin air that helped our ancestors to survive through all odds and to make the right choices for their survival.

Today odours are still signals, as they build a very complex symbology in various areas of our life. 

There are several aspects relating to odor which involve all our activities, from sport to social relationships, so it is not strange that this problem is being targeted in many different ways since many years.