But the new device Zhou and her team designed tells a different story. It detects the beginning of a sniff using changes in nasal pressure and then triggers the release of two odors, with one slightly farther from the nose than the other.

More than 200 participants were exposed to the sequences of two chemical odors in a single sniff. [...]

Test subjects were able to discern different sequences with above-chance accuracy, even when the odors were delivered only 60 milliseconds apart. The results suggest that our sense of smell has a speed similar to that of color perception.

— Read more in Your brain can perceive subtle odor changes in a single sniff at Science News.