Chemical Engineering News has published the above drawing by Andy Brunning, author of the popular graphics blog Compound Interest, on the mechanism how air fresheners ‘kill’ bad odors. Some air fresheners mask bad smells, while others claim to eliminate odors completely.
The three main strategies:
Air freshener aroma compounds mask bad smells. They include terpenes such as limonene and alpha-pinene. Some people have expressed concern that these can react with ozone to produce formaldehyde, a carcinogen.
Some air fresheners use organic acids, which can react with smelly compounds to break them down to more benign molecules.
Cyclodextrins are ring-shaped molecules made from cornstarch. Odor molecules get caged within cyclodextrin cavity, stopping them from reaching your nose.
The Febreeze series of Procter & Gamble use this mechanism applying HPBCD solution to remove bad odor from fabric and from air.