We already have white noise, and now there an equivalent for smell. Scientists in Israel believe they've identified "olfactory white", a blend of dozens of components that smells — well — totally neutral.
They created olfactory white by taking a large number of unrelated molecules that smell wildly different, and combining them at the same level of intensity. While strong and pungent odors may have dozens of smells, usually they're related or there's a strongly dominant note. With olfactory white, everything is reduced to the same level, evening it out, much like white noise.
Even more interesting, it doesn't matter where those smell components come from. A mix of 30 disparate smells from across the olfactory space will produce much the same olfactory white smell as those from another batch of 30 odorants without any crossover. In fact, participants in the study were trained to identify the smell — dubbed Laurax for the study — and then when exposed to other blends, the more odorants used the closer they identified it to the Laurax smell.
As bizarre of a study as this is, it actually lends itself to some pretty cool theorizing. For now, the scientists are working on a more efficient way of making the smell that might not require 30 odorants, or maybe a more "pure" olfactory white, but there seem like many other possible uses for Laurax. Could it be used to mask other odors? Anyone who has ever accidentally unleashed a foul smelling hell in their kitchen would love a smell that actually covers the more offensive stuff with something neutral. Or maybe this will lead to a true deodorant?
There's also been some work that suggests that hearing problems like tinnitus could be helped by "resetting" the brain to a more neutral state. Could olfactory white be used to the same end for people with smelling disorders?