Heather Murphy in the New York Times:
The scent of lily of the valley cannot be easily bottled. For decades companies that make soap, lotions and perfumes have relied on a chemical called bourgeonal to imbue their products with the sweet smell of the little white flowers. A tiny drop can be extraordinarily intense.
If you can smell it at all, that is. For a small percentage of people, it fails to register as anything.
Similarly, the earthy compound 2-ethylfenchol, present in beets, is so powerful for some people that a small chunk of the root vegetable smells like a heap of dirt. For others, that same compound is as undetectable as the scent of bottled water.
These — and dozens of other differences in scent perception — are detailed in a new study, published this week in the journal PNAS.