The training of dogs should run concurrent with trying to identify the molecule. I bet it is a hell of a lot cheaper to teach a dog to detect a scent, then a machine to find the molecule.
I find it amazing that while we have created technologies that greatly improve on our sense of sight and hearing, we still haven’t mastered the sense of smell to a level that our four-legged companions have. It seems like it would be a fruitful area of research.
While humans have decent sense of smell, a dog’s is 1,000 times better. Thereforhereunder, “cadaver dogs”, who can alert on drowning victims under water!