Why do we stop noticing the smell when we are for a long time in any room with the source of this smell?

I would like to share, in my opinion, some interesting observations. At that time, when I lived with my parents, who are heavy smokers, who believe that smoking in the apartment is normal, I did not feel at all "smoky" in the apartment, although all the guests told me about it. I did not notice this smell after a two-week vacation at the sea and in the forest, but after working as a volunteer in the elections, when in one day I had to go around about 30-50 of the most diverse apartments, with a wide variety of smells, from the smell of urine to the smell of pepper, I immediately caught the smell of his own apartment.

This phenomenon is accommodation. All receptors, not only tactile ones, under constant influence within certain limits can get used to irritation (pain receptors never fully adapt, but tactile receptors adapt well). An evolutionary mechanism that allows living things to adapt to different external conditions. Not to notice persistent smells, which, therefore, do not carry new information. The mechanism for different receptors is different. Read more: http://meduniver.com/Medical/Physiology/928.html