Olfactory Displays - Environmental Awareness

To date, smell has been used infrequently in information displays. Most of these have used the olfactory system's characteristic of working in background until a change in our environment occurs--at which time we "notice" the change, that is, we become aware of the smell.

The most familiar use of smell for information display is the addition of mercaptan, a sulfur compound, to natural gas which is odorless to warn of a gas leak. Another less well known use is the injection of mercaptan into mines as an evacuation signal. Sulfur compounds smell of “rotten eggs” and are easily detected and discerned by the human olfactory system. We can smell one part of mercaptan at less than one part per billion.

"Stench systems" are used in some mines to inject mercaptan, the smell of rotten eggs, into the mine to signal evacuation. In this instance, use of the sense of smell is adjunct to visual and auditory displays that may not be able to be perceived by miners depending upon where they are in the mine. (Photo, USGS)