Human Nose Can Detect a Trillion Smells, according to a new study. Researchers had previously estimated that humans could sense only about 10,000 odours but the number had never been explicitly tested before.
“People have been talked into this idea that humans are bad at detecting smells,” says neurobiologist Leslie Vosshall of Rockefeller University in New York City
Humans detect smells by inhaling air that contains odour molecules, which then bind to receptors inside the nose, relaying messages to the brain. Most scents are composed of many odourants; a whiff of chocolate, for example, is made up of hundreds of different odor molecules. Understanding how people process the complex information contained in scents—or memories of smells—offers a window into how the human brain functions.