Many studies have linked exposure to nature to a wide variety of health benefits, from improved cognitive function to lower blood pressure and better mental health. Other research has found connections between the human microbiome and time spent outdoors. But an overlooked, understudied player in this relationship is the set of microbes found in the nose, or the nasal microbiome.
Researchers at the Denver Museum of Nature and Science recently set out to bridge that gap. In a study conducted at the museum—and by inviting 111 museum visitors to join the cohort—microbiologists identified nasal microbial signatures and patterns associated with mental well-being and participants’ exposure to parks and other green spaces.
Genomics scientist Bridget Chalifour, Ph.D., principal investigator at the museum, led the study and presented the results of the analysis at ASM Microbe 2026 in Washington, DC
The museum houses a genomics lab inside the building where Chalifour works and where visitors can observe through glass walls. For this study, he said, participants were asked to contribute nasal swabs and complete validated surveys with questions about mental well-being, time spent outside and pet ownership. Collecting the smear samples was easy. “After Covid, people are very adept at taking their own nasal swab,” Chalifour said.
She and her colleagues used 16S rRNA sequencing to map participants’ nasal microbiomes and recruited the museum’s research team of scientists to locate green maps for participants based on their addresses, using publicly available satellite data.
Their preliminary analyzes 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 harbored a wider microbial diversity in their noses, with certain microbes appearing more or less often depending on the green space in their neighborhood.
We tend to associate greater diversity and richness with a healthier microbiome.”
Bridget Chalifour, Ph.D., principal investigator at the museum
Some of the same microbes that were associated with more reported time spent outdoors were also associated with better mental health scores.
The analysis also showed that time spent outside had a stronger association with a healthy nasal microbiome than exposure to green spaces. “The timing was really important in all respects,” he said. “People who spent more time outdoors, regardless of how green it was, had lower depression scores overall.”
And, digging a little deeper, he noted that the nasal microbiome appears to respond to these choices—and may help facilitate positive changes in mental well-being. “People are changing their microbiomes just by spending more time in nature,” he said.
The study represents one of the museum team’s first forays into microbiology, Chalifour said, but the institution already has a strong tradition of scientific research in many fields. “We do a lot of real research at the museum,” he said.
