(Press-News.org)
When it comes to the air in public places, germophobes can breathe a bit easier. According to a new Northwestern University study, the ambient air on airplanes and in hospitals mostly contains harmless microbes typically associated with human skin.
In the first study of its kind, scientists used an unexpected sampling tool — used face masks and an aircraft air filter — to uncover the invisible world of microbes floating in our shared air. Their results revealed that the same types of harmless, human-associated bacteria dominate both airplane and hospital air.
Across all samples, the team detected 407 distinct microbial species, including common skin bacteria and environmental microbes. While a few potentially pathogenic microbes did appear, they were in extremely low abundance and without signs of active infection.
Not only does the study help illuminate what microbes exist in shared air, but it also demonstrates that face masks and air filters can be repurposed as non-invasive, cost-effective tools to monitor confined, high-traffic environments.
The study will be published on Wednesday (Dec. 3) in the journal Microbiome.
“We realized that we could use face masks as a cheap, easy air-sampling device for personal exposures and general exposures,” said Northwestern’s Erica M. Hartmann, who led the study. “We extracted DNA from those masks and examined the types of bacteria found there. Somewhat unsurprisingly, the bacteria were the types that we would typically associate with indoor air. Indoor air looks like indoor air, which also looks like human skin.”
An expert on indoor microbiomes, Hartmann is an associate professor of civil and environmental engineering at Northwestern’s McCormick School of Engineering.
A second life for used face masks
Hartmann and her team conceived the project in January 2022, amid the COVID-19 pandemic. At the time, travelers became increasingly concerned with how well airplane cabins filtered and circulated air. Hartmann received a grant from the Walder Foundation to collect airplanes’ cabin filters to look for evidence of pathogens.
Although Hartmann did procure an aircraft’s high-efficiency particulate air (HEPA) filter, which had been used for more than 8,000 flight hours, she quickly realized the project might be impractical.
“At the time, there was a serious concern about Covid transmission on planes,” Hartmann said. “HEPA filters on planes filter the air with incredibly high efficiency, so we thought it would be a great way to capture everything in the air. But these filters are not like the filters in our cars or homes. They cost thousands of dollars and, in order to remove them, workers have to pull the airplane out of service for maintenance. This obviously costs an incredible amount of money, and that was eye opening.”
Searching for another method that passively traps microbes, Hartmann and her team pivoted to a much cheaper and much less disruptive tool: face masks. For the study, volunteers wore face masks on both domestic and international flights. After landing, they put the masks into sterile bags and sent them to Hartmann’s lab. For comparison, Hartmann also collected face masks that volunteers took on flights but never wore.
To understand how indoor environments differ, Hartmann and her team wanted to examine another high-traffic, enclosed environment with heavily filtered air. The team selected hospitals as the second testbed. After wearing a face mask during a shift, hospital workers submitted their masks to Hartmann’s lab.
“As a comparison group, we thought about another population of people who were likely wearing masks anyway,” Hartmann said. “We landed on health care providers.”
The sky is clear
After receiving masks from travelers and health care workers, Hartmann’s team collected DNA from the outsides of masks. They found the air in hospitals and on airplanes contains a diverse but mostly harmless mix of microbes, with only minimal traces of potentially pathogenic species.
In both environments, common human-associated bacteria — especially those found on skin and in indoor air — dominated the samples. Although the abundance of each microbe present was slightly different, the microbial communities from hospitals and airplanes were highly similar. The overlap suggests that people themselves — rather than the specific environment — are the main source of airborne microbes in both settings. And those microbes floating around indoor air come from people’s skin, not from illness.
Hartmann’s team also identified a handful of antibiotic resistance genes, linked to major classes of antibiotics. While these genes do not indicate the presence of dangerous microbes in the air, they highlight how widespread antibiotic resistance has become.
Although indoor air might not be as harmful as some people may have feared, Hartmann emphasizes that airborne spread is just one way infections can travel. For many common illnesses, other routes — such as direct contact with an infected individual or interacting with high-touch surfaces — are far more important.
“For this study, we solely looked at what’s in the air,” Hartmann said. “Hand hygiene remains an effective way to prevent diseases transmission from surfaces. We were interested in what people are exposed to via air, even if they are washing their hands.”
The study, “Metagenomic profiling of airborne microbial communities from aircraft filters and face masks,” was supported by the Walder Foundation (award number 21-00661).
END
Biased or misleading medical advice shared by social media influencers can cause harm and requires coordinated action by governments and platforms to protect the public, argue experts in The BMJ today.
Social media influencers are a growing source of medical advice, say Raffael Heiss and colleagues. More than 70% of young adults in the US follow influencers, and over 40% have purchased products based on their recommendations.
Yet they warn that influencer advice can be subject to four sources of bias: lack of ...
Recommendations introduced in Australia and being considered in the UK to tell women if they have dense breasts as part of their screening results may have unintended effects and increase demand on health services, finds a clinical trial designed to assess the real-world impact of notification, published by The BMJ today.
The results show that women who were notified of their dense breasts (which can hide small cancers on a mammogram, making them harder to detect) felt more anxious and confused about their breast health 8 weeks after their screening appointment, ...
A new study suggests that traditional learning activities like making notes remain critical for students’ reading comprehension and retention, while also suggesting that large language models (LLMs), such as ChatGPT or Microsoft Copilot, could be a useful tool for helping students clarify, explore, and contextualise learning material.
Although many students are already using LLMs, there is a lack of research on the impact of generative AI on the fundamental processes of learning.
The study by Cambridge University Press & Assessment and Microsoft Research, which is published today (Thursday) in the ...
UNDER EMBARGO UNTIL 00:01 GMT THURSDAY 04 DECEMBER 2025 / 19:01 ET WEDNESDAY 3 DECEMBER 2025
An international team led by the University of Oxford has identified one of the largest rotating structures ever reported: a “razor-thin” string of galaxies embedded in a giant spinning cosmic filament, 140 million light-years away. The findings, published today (4 December) in Monthly Notices of the Royal Astronomical Society, could offer valuable new insights into how galaxies formed in the early Universe.
Cosmic filaments are the largest known structures in the Universe: vast, ...
Leber Congenital Amaurosis (LCA) is an inherited retinal disease leading to severe vision impairment from early infancy, affecting 2-3 out of every 100,000 newborns. LCA is caused by variants in certain genes from which proteins essential for retinal cell function and survival are made. Mutations in over 20 different genes can cause LCA and in each of those genes, hundreds of different changes, known as genetic variants, can occur. Importantly, while some of these genetic variants are benign and do not compromise function, other variants cause dysfunction or complete loss of function. Further, for some of these variants, which are called variants ...
A new perspective published in Biocontaminant outlines an urgent scientific roadmap for understanding how common chemicals interact with microbial communities to accelerate the global crisis of antimicrobial resistance. The work, led by Ji Lu from the University of Queensland, highlights why traditional single chemical experiments fail to capture the real drivers of resistance in natural and clinical environments.
“Chemicals rarely occur alone in the real world. They mix, react, and interact with diverse microbiomes in ways that can either amplify or suppress antimicrobial resistance,” said Dr ...
Heavy metals in soil are often measured in bulk, but those totals can badly overestimate the real risk to crops, ecosystems and human health, according to a new scientific review. The article, published in Environmental and Biogeochemical Processes, explains that only a fraction of the metal present in soil is actually accessible to plants, microbes and people – a concept known as bioavailability.
“Metal pollution in soil is a genuine global concern, but decisions about food safety, clean‑up and land reuse need to be based on ...
A rare and life-threatening kidney disease in children finally has an effective therapy, thanks in large part to pioneering research and clinical leadership from University of Iowa Health Care Stead Family Children’s Hospital.
The disease, known as C3 glomerulopathy (C3G), is an ultra-rare condition that primarily affects children and young adults. Only around 5,000 Americans have C3G, which causes progressive kidney damage, with more than half of patients reaching end-stage kidney failure within a decade of diagnosis.
Unlike previous treatments for C3G that aimed to alleviate ...
A research team from NIMS, Tohoku University and AIST has developed a new technique for controlling the nanostructures and magnetic domain structures of iron-based soft amorphous ribbons, achieving more than a 50% reduction in core loss compared with the initial amorphous material. The developed material exhibits particularly high performance in the high-frequency range of several tens of kilohertz—required for next-generation, high-frequency transformers and EV drive power supply circuits. This breakthrough is expected to contribute to the advancement of these technologies, development of more energy-efficient electric machines and progress ...
Thulium fiber lasers, operating at a wavelength of 2 micrometers, are valued for applications in medicine, materials processing, and defense. Their longer wavelength makes stray light less damaging compared to the more common ytterbium lasers at 1 micrometer. Yet, despite this advantage, thulium lasers have been stuck at around 1 kilowatt of output power for more than a decade, limited by nonlinear effects and heat buildup. One promising route to break this barrier is inband pumping—switching from diode pumping ...
