Specialists: Bacteria in the air on airplanes and in hospitals pose no threat.

People concerned about germs can feel more at ease when flying or visiting medical facilities, according to a recent scientific study. Research published in Microbiome reveals that the air in airplanes and hospitals is primarily populated by harmless microbes typically found on human skin.

The study examined microorganisms collected from the exterior of face masks worn by airline passengers and healthcare workers. Face masks turned out to be an inexpensive and simple way to sample air exposure for individuals and general environments, explained Erica Hartmann, an associate professor of civil and environmental engineering at Northwestern University in Illinois. We extracted DNA from the masks to identify the bacteria present.

Samples were gathered from masks worn by 10 airline passengers after flights and 12 healthcare staff members after their shifts. Additionally, researchers analyzed microbes trapped in a cabin air filter that had been in use for over 8,000 hours.

In total, 407 distinct microbial species were identified. The bacteria we found are what you would expect from indoor air, Hartmann said. Indoor air microbiomes closely resemble the microbial profile of human skin. A small number of potentially harmful microbes were detected, but in extremely low quantities and without evidence of active infection.

The project began in January 2022 during the COVID-19 pandemic, when concerns about virus transmission on airplanes were high. HEPA filters on planes remove airborne particles with exceptional efficiency, making them ideal for capturing microbes, Hartmann noted. She added that these filters are expensive and require taking planes out of service for maintenance, which highlighted the practicality of using masks as a sampling tool. Hospitals were included in the study as a comparison group, given that healthcare workers routinely wear masks.

Findings suggest that humans are the primary source of airborne microbes in enclosed spaces, with most microbes originating from skin rather than illness. While indoor air appears generally safe, researchers emphasize that infections can still spread through other means, particularly via touch. This study focused solely on airborne exposure, Hartmann said. Hand hygiene remains critical for preventing disease transmission from surfaces.

Author: Harper Simmons