There's a host of smells that accost your nose every time you walk outside—some good, some not. Researchers have started mapping these odors to determine each city's smellscape, and perhaps how to improve it.
Cities agencies only track a few really nasty smells for the purpose of alleviating them. So, a team at the University of Cambridge had volunteers walk around cities and note what their nose noticed. Individual scents like lavender and trash were grouped into ten larger categories and charted to determine the dominant smells in a city. Barcelona has a heavy nature smell, for example, while London's largest category is emissions.
Daniele Quercia, one of the researchers, hopes that smellscapes might factor into future city planning and integrate into services like Google Maps. "For example, runners might wish to avoid emission-infused streets," he says.