Scientists discover the 'white noise' of smells

File photo / NZ Herald

A new smell discovered by scientists is being hailed as the nasal equivalent of white noise.

Researchers from the Weizmann Institute in Israel sought to create for the olfactory equivalent of white noise or white light, hypothesising that just as white noise is a combination of many frequencies and white light is a combination of many wavelengths, an "olfactory white" could be created based on the same principal.

The researchers concocted 86 different odorants, each of an equal intensity. Samples of these were then mixed together to create a range of odor samples, each containing between one and 43 of the different basic odorants.

A group of 59 volunteers were then asked to rate pairs of the samples as to how close they smelled to one another.

The key to creating olfactory white, the researchers discovered, was not the compounds used, but rather the amount of different compounds used.

"The more components there were in each of two mixtures, the more similar the smell of those two mixtures became, even though the mixtures had no components in common," they wrote.

The researchers found participants could not tell the difference between samples containing 30 or more odorants, regardless of whether any of the ingredients were the same.

Samples with this many odorants had a distinct odor itself, which was named "Laurax" by the researchers.

The findings have been published in November 20 Proceedings of the Natural Academy of Sciences in the United States of America.