Sensory Fatigue

Sensory fatigue refers to the inability or decreased ability to perceive an odour. This increases over time as exposure continues. An odour may initially be strongly detectable but may diminish completely in a few minutes. For example, Hydrogen sulphide is an example of a chemical that emits a rotten egg smell. However, depending on concentration and exposure time, the rotten egg smell will no longer be perceived. Olfactory fatigue is not desired during olfactometry analysis or ambient odour monitoring.

During ambient odour monitoring, it is desired to provide rest periods in a neutral environment compared to the one odour is present if possible. An example may include a vehicle, which could act as a separate environment to the one ambient odour monitoring is taking place. Perfumeries use coffee bean odour to ‘reset’ the olfactory sense. Also, having a neutral odourless air to be smelled for a few minutes may help reset the olfactory sense.