The term is also used in the study of indoor air quality, for example, in the perception of odors from people, tobacco, and cleaning agents.
When odorants bind receptors on ORNs, Ca2+ ions flood into the cell causing depolarization and signaling to the brain.
Increased Ca2+ also activates a negative, stabilizing feedback loop which lowers the olfactory neuron's sensitivity the longer it is stimulated by an odorant to prevent overstimulation.
[4] The influx of Ca2+ ions through this channel triggers olfactory adaptation immediately because Ca2+/calmodulin-dependent protein kinase II or CaMK activation directly represses the opening of cation channels, inactivates adenylyl cyclase, and activates the phosphodiesterase that cleaves cAMP.
[6] According to a study by Grosofsky, Haupert and Versteeg, "fragrance sellers often provide coffee beans to their customers as a nasal palate cleanser" to reduce the effects of olfactory adaptation and habituation.