Urban smellscapes
Bostonians, rejoice! The city was recently crowned the best smelling in the US—at least according to a press release that found its way into the Newscripts inbox.
Per the email, online casino McLuck.com performed the study by generating smell scores for the 30 largest US cities. The scores are based on cleanliness data and the density of sweet-smelling shops—candle and perfume stores, florists, and bakeries were all included.
By these metrics, Boston ranks number 1 with a score of 9.64 out of 10.00, while Jacksonville, Florida, is dead last with a score of 3.91. But is it really that easy to quantify an urban perfume?
“They’ve assumed that everybody likes a candle store,” smell researcher Kate McLean-MacKenzie tells Newscripts. “I run a mile if you send me near a candle store because I find them completely overwhelming.”
Rather than appraising urban odors, McLean-MacKenzie documents a city’s smellscape through the noses of the people who live there. These maps encapsulate “the geography of places that come about through human perception,” she explains. Smell walks provide the data. As participants walk for a kilometer or two, she directs them to notice and describe what pricks their noses.
McLean-MacKenzie is building an atlas of odors from the collected descriptions. “I’ve got some nice ones from Boston,” she says. Some sounded pleasant—“cold, salty ocean air . . . cotton candy, gelato, cannoli in Boston’s North End . . . Family cookouts.” Others are less nice—“hot, stale air; brake dust . . . summer trash and sulfur.”
Ultimately, McLean-MacKenzie hopes to paint nuanced portraits of local environments. More than dubbing one place better smelling than another, the project is about “realizing just how complex our olfactory worlds are and really, how much we can smell if we pay attention,” she says.
Canine breath freshener
As this Newscriptster contemplated naming the smells of day-to-day life, one in particular came to mind: puppy kisses. Or, in less idealized parlance, dog breath.
A dog’s “bad breath is a scientific problem, not just a superficial odor problem,” writes Hongye Li, a researcher at Jiangnan University, in an email to Newscripts. “Behind the smell, there are real odor molecules and real microbial metabolic processes.”
Li wanted to apply his expertise as a food scientist, microbiologist, and dog owner to tackle this practical problem. That desire led him and his team of researchers to develop a new breath spray for our canine companions.
The options available today largely rely on masking foul dog breath with pleasant fragrances, Li says. He and his team wanted to target hounds’ halitosis head-on. Sugar cane polyphenols offered a solution (J. Agric. Food Chem. 2026, DOI: 10.1021/acs.jafc.6c00022).
These polyphenols can interact with odorous volatiles directly, trapping them in dog slobber before they float into the air, where humans can smell them. Microbial analysis also showed that the spray prevents oral microbes from producing smelly compounds in the first place. And repeated use may actually shift a dog’s oral microbiome away from odoriferous bacteria.
The scientists enlisted 10 dogs to trial their new spray. Five brave human panelists took whiffs of the dogs’ mouths before and after a spritz. Within minutes, the evaluators reported an improvement, Li says. Subsequent chemical analysis with mass spectrometry agreed; a variety of volatile compounds measurably decreased, Li says.
The spray won’t reach shelves anytime soon, however—it needs further evaluation for safety, stability, and long-term use, Li says. Still, he wants the work to encourage the development of oral-care products that do more than mask nasty scents.
He says, “I hope our work can help dogs stay healthier and make every hug, every lick, and every moment shared between people and their dogs a little more enjoyable.”
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