The scent of garbage stewing in the afternoon heat is enough to make most people want to turn off their noses for a minute or two. How quickly we forget about all the good aromas our noses bring us.

Most of us don’t realize how much work our noses do to bring us classic scents such as baking cookie and fresh-ground coffee… or wet dog and too-much-cologne. New research from the University of Pennsylvania shows that our sense of smell actually works twice as hard as any other sense, picking up two different types of stimuli to bring us the smells we detect. Most other senses are driven by only one stimulus.

Neurons in the nose respond both to chemical stimuli… odors… and mechanical stimuli… the air pressure generated by breathing in. The researchers say this is why sniffing or inhaling something is necessary to actually smell it. Your nose’s sensitivity to this physical process actually heightens your ability to sense odors, even weak ones.

Reactions to scents as well as the physical act of inhaling produce the same molecular messenger that acts as a sort of smell alert for your brain. To get that smell, though, molecules from whatever you’re sniffing actually have to travel into your nose and cling to the cilia [sill-ee-ah], which extend from the scent-detecting neurons in the nose.

So you may actually want to thank your nose next time you’re ready to pinch it shut. Even if something smells a little stinky.