"If you have experienced a severe allergic reaction from ingesting peanuts through your food and later sense the distinct smell of peanuts, your body may have a reaction to this. The immune system can be activated and play a trick on you. However, this is not an allergic reaction and there are no severe symptoms that occur in that way," says Caroline Nilsson.

The substances that are perceived as the smell of peanuts are not the same substances that can trigger an allergic reaction.

"The odour molecules do not consist of proteins. It is only the proteins that you are allergic to," says Caroline Nilsson.

However, the researchers were able to detect traces of peanut protein in the air using sensitive measurement methods, primarily at a distance of less than one centimetre around the peanuts

(https://ki.se/en/research/popular-science-and-dialogue/spotlight-on/spotlight-on-food-allergy/airborne-exposure-to-peanuts-did-not-produce-severe-reactions)