A "White Smell" Could Hide The Most Repellant of Odours

Imagine eternally odorless public restrooms, or stink-free changing rooms. Amazingly, researchers claim to have discovered what they're calling a "white smell"—an odor made up so many complex aromas that it's neither pleasant or foul-smelling, in no way overwhelming, and could be the most effective air-freshener ever.

Taking its name from the concept of white noise—sound which contains all frequencies—the researchers have dubbed the concept "olfactory white". They stumbled across the idea during experiments that mixed aromas from across the scent spectrum. We're not joking. As Nature explains:

[I]f two mixtures had no components in common, they tended towards having a similar scent as more aromas were added. By the time they contained about 30 components, most mixtures smelled alike, and could mask other distinctive smells.

It's a weird ol' finding, which is published in PNAS—and it's not particularly intuitive. Our noses are packed with hundreds of different odor receptors—unlike, say, our tongue with its basic range of tastebuds—so you'd probably think that smells should just become more deep and complex as scents are added.

Clearly not. In fact the concept has been tested in numerous experiments by scientists from the Weizmann Institute of Science in Rehovot, Israel, and each time they observe the same result: as more and more scents are added to a smell, the closer it gets to smelling like a consistent white smell. While the physical mechanism for the phenomenon remains unclear, it's clearly a real effect.

The most interesting part of the finding, though, is the way in which the white smell can obscure offensive odors. That means the theory could be used to generate incredibly effective ways to mask whiffs—from public toilets to sweaty gyms, and anything else you care to think of. It can't come soon enough. [PNAS via Nature]

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