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Washington, D.C. — Plenty of studies have linked exposure to nature to a wide variety of health benefits, from improved cognitive function to lower blood pressure to better mental health. Other research has found connections between the human microbiome and time spent outside. But an overlooked, understudied player in that connection is the assemblage of microbes found in the nose, or the nasal microbiome.
Researchers at the Denver Museum of Nature & Science recently set out to bridge that gap. In a study conducted at the museum—and by inviting 111 museumgoers to join the cohort—the microbiologists identified nasal microbial signatures and patterns associated with the participants’ mental well-being and exposure to parks and other green spaces.
Genomics scientist Bridget Chalifour, Ph.D., a principal investigator at the museum, led the study and presented the results of the analysis at ASM Microbe 2026 in Washington, D.C.
The museum hosts a genomics lab within the building, where Chalifour works and where visitors can observe through glass walls. For this study, she said, participants were invited to contribute nasal swabs and complete validated surveys with questions about mental well-being, time spent outside and pet ownership. Collecting the swab samples was easy. “After Covid, people are very skilled at taking their own nasal sample,” Chalifour said.
She and her collaborators used 16S rRNA sequencing to catalog the nasal microbiomes of participants, and they enlisted the museum’s earth scientists research crew to identify green space maps for the participants based on their addresses, using publicly available satellite data.
Their preliminary analyses suggest that green space and pet exposure significantly influence the composition of the nasal microbiome, and in ways consistent with previous studies on microbes and mental health. They found that people who lived around more vegetation hosted a wider microbial variety in their noses, with some microbes showing up more or less often depending on the green space in their neighborhood. “We tend to associate greater diversity and greater richness with a healthier microbiome,” Chalifour said. Some of the same microbes that correlated with more reported time spent outdoors were similarly associated with better mental health scores.
The analysis also showed that the time spent outside had a stronger association with a healthy nasal microbiome than exposure to green space. “Time was really important in all aspects,” she said. “People who spent more time outdoors, regardless of how green it was, had lower depressive scores overall.”
And, drilling a little deeper, she noted that the nasal microbiome seems to respond to those choices—and may help facilitate the positive changes in mental well-being. “People are changing their microbiomes just by spending more time in nature,” she said.
The study represents one of the museum team’s first forays into microbiology, said Chalifour, but the institution already has a robust tradition of scientific inquiry across many fields. “We do a lot of real research at the museum,” she said.
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