The study, published last week in the Journal of Exposure Science & Environmental Epidemiology, examined air and surface samples during an environmental surveillance programme from August 2020 until April 2021 at the University of Michigan (U-M) in the US.
The researchers looked at public spaces, including classrooms, rehearsal rooms, cafeterias, buses, gyms, student activity buildings, and ventilation and air ducts.
As the study was conducted during lockdowns in a college campus, no samples were collected in spaces with large gatherings of people and some samples were only collected when few people were present.
For air samples, they used wetted wall cyclone bioaerosol samplers, which suck in large volumes of air using a pump and capture any virus particles in the air.