Scents & Sensibility

These smelly city maps know where noses should and shouldn’t go.

If smell is the most evocative sense, then breathing in a city is an emotional roller coaster that can go from parfum de park to eau de garbage faster than you can say “pee-ew!” Working with the hypothesis that smells—the good, the bad, the toxic—influence the quality of urban life, a team of researchers has given order to all that odor with color-coded maps that illustrate the variegated smellscapes of cities.

First, the researchers created a 285-word urban smell dictionary based on the detailed notes of volunteers who took “smell walks” through their cities. Then they matched up GPS locations with photo tags for those words on social media sites. The system works—places with high concentrations of pollutants (officially measured) were positively correlated with words describing emissions smells like “gasoline” and “exhaust,” and negatively correlated with words describing natural smells like “grass.” So far, London and Barcelona have the only smelly maps out there, but other city dwellers are sure to be hot on the scent for better scents.  

Smell map of London illustrated by Daniele Quercia, Rossano Schifanella, Luca Maria Aiello, and Kate McLean showing emissions smells in red and nature smells in green.

Smell map of Barcelona illustrated by Daniele Quercia, Rossano Schifanella, Luca Maria Aiello, and Kate McLean showing emissions smells in red and nature smells in green.

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