Humans Can Smell One Trillion Different Scents, Study Finds

By Wendy Rodewald-Sulz / March 26, 2014

Living in New York City is such a daily olfactory adventure that I often think perfumers should train here instead of in Grasse. The French perfume capital has its fields of flowers, sure, but New York is a true melting pot of odor: the stretch of curry restaurants on Lexington Avenue, the musty-smelling subway weirdos, the trees that smell like bodily fluids when they bloom, the mysterious recurring maple syrup scent that wafts over from the chemical factories of New Jersey. Sometimes the range of smells a person can experience here seems infinite.

As it turns out, that’s almost correct. A new study has found that humans can, in fact, detect approximately one trillion different scents. That’s a pretty big jump from the 10,000 or so smells science once believed the human nose could distinguish. The Atlantic summarizes the study, which was published in the magazine Science:

“Unlike sight, where there are only a set number of light wavelengths that we can (or cannot) see, scents are made up of hundreds of different molecules, so the number of odor combinations is practically infinite. This means that it is very difficult to test our capacity for smell, so although the assumption was capped at 10,000 odors, it was never actually tested.

To get around this problem, the researchers combined 128 common scents, like orange and peppermint, into new smells containing 10, 20, and 30 of these different odor molecules. They then had participants compare three vials of these odor combinations, two of which were the same and one that was different, and try to pick out which one was not like the other.”

The study’s lead author, Dr. Andreas Keller, sums it up: “The message here is that we have more sensitivity in our sense of smell than we give ourselves credit for. We just don't pay attention to it and don't use it in everyday life.” Oh yeah? This New Yorker would beg to differ.

Study: Humans Can Smell 1 Trillion Scents [The Atlantic]

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