Febreze commercials make a very specific claim. They say their spray is better at deodorizing a smelly room than pungent incense or a fragrant candle because it doesn't just cover offending smells with oppressive florals, it "eliminates" them. But how is that even possible?
This new video from the American Chemical Society's Reactions series tackles exactly that question with a look at the chemical composition of odors. It turns out, Febreze really does "trap" the unpleasant smells by deploying cage-like chemical compounds called cyclodextrins. The centers of the funnel-shaped cyclodextrins are extremely hydrophobic, which means they attract other hydrophobic molecules, including those that are responsible for most aromas. Hydrophobic stinky scents get trapped inside the cyclodextrins, rendering them unable to reach the receptors in your nose. This leaves the intentionally hydrophilic perfumes added to the Febreze to flood your senses with more appealing scents.
But while we know how Febreze works, we still don't quite fully understand how we smell smells, as chemist Chad Jones explains in the video. We do know that volatile molecules—ones that evaporate quickly and enter the air—bind to olfactory receptors, which then send a message to the brain about the nature of the chemical. As two Nobel Prize–winning researchers discovered, these receptors are highly specialized and can detect only a few kinds of odors.
"What we're not sure about is how the receptors work," Jones says. "Some say the receptors work like a lock and key, with the molecule acting as a 'key' in the 'lock' receptor. Others suggest that because each molecule vibrates in its own special way, the receptors can detect these vibrations."
[h/t Washington Post]