Linda Poon is a staff writer at CityLab covering science and urban technology, including smart cities and climate change. She previously covered global health and development for NPR’s Goats and Soda blog.
Why smell expert Sissel Tolaas is on a mission to capture and replicate the “smellscapes” of cities around the world.
If you closed your eyes, could you navigate your city or neighborhood using only your sense of smell?
“Yes! And in a very sophisticated way,” says Sissel Tolaas, who’s been studying smells since the early 1990s. “We are equipped with amazing software … that helps us navigate, understand, and communicate with the world.”
Tolaas sticks her nose in everything, from doorknobs to car seats to even people. She calls herself a “professional inbetweener,” switching between scientist and artist, and fusing her odor research with her studies on language and communication.
Part of her job includes working with the likes of architects, environmentalists, and even commercial companies to create “smellscapes” of different cities, including Berlin, Mexico City, and Kansas City, Missouri. She’s been doing this since the early 2000s and already has smell profiles of 35 cities in her library. Altogether, she has a collection of more than 7,000 scents from various projects in her Berlin laboratory.
In Kansas City, Tolaas was tasked with identifying and recreating smells that captured the city’s diversity. So Tolaas took participants on a nose-first scavenger hunt through a handful of neighborhoods and had them note the sources of smells that stood out—bakeries, laundromats, Ethiopian and Haitian restaurants, and even garbage and body odor.
To Tolaas, there’s no such thing as a good or bad smell. That, she says, is a product of prejudice people are taught early on. “In my world, there is no hierarchy within smells,” she tells CityLab. “Every smell has the potential of being interesting.”
Capturing a city’s smells, she says, requires some creativity. What she deems as part of a city’s smellscape can’t scientifically be proven by using, say, lab rats. So she uses her own nose (and those of volunteers) to identify a smell and find the source of it. Then she brings a sample of the object back to her lab and extracts the odor molecules using a machine supplied by International Flavors & Fragrances Inc. The company also helps her identify the key molecules, and Tolaas gets to work on making a synthetic replicate of the smell.
While not full-on science experiments, she does try to collect odors that are constant. “I walk down the street early in the morning, in the middle of the day, and the evening to reassure that the smell is not just something that you pass by one second, and in the next second it's gone,” she says. “It has to be permanent.”
Her latest project, with Harvard University, took her to Shanghai, where she and a team of local student volunteers collected more than 500 unique scents. A lot of the smells came from food, Tolaas recalls, but there was also odor from people, car exhaust, and the river. She remembers the students were initially reluctant about sticking their noses in everything, but soon, many told her that they wanted to continue the project.
“It’s a wake-up call, you know?” she says.
Tolaas thinks we don’t use our noses enough. And really, that’s what her projects are about: reconnecting humans with their noses. Evolutionarily, she points out, human noses were used to find food, shelter, and partners. But now, “we are asked to smell commercial products, perfume, etc., but we're never asked to smell a city, to smell each other,” she says. “It's not fair toward the body, humanity, or the world.”
Yet the smells of a city or your neighbor provides stories and background that can’t necessarily be seen, like someone’s cultural background or the events that have taken place inside a house or community. So she wants to retrain people to use their nose, teaching kids how to gather information through scent and ridding adults of their prejudices toward smells.
It’ll come especially handy in a world that Tolaas says is driven by how something looks. “Tolerance doesn’t start with how you look and what you believe; it starts with how things smell.”