Ventilation and student placement can affect how coronavirus particles move around a classroom, according to a study published on Tuesday in the journal Physics of Fluids. The study also found that removing some seats, opening windows, placing glass barriers on desks and focusing on hand hygiene may help to reduce spread of the virus.
The authors conducted 20 computer simulations of how particles could spread based on a classroom including nine students and an instructor and desks with and without glass screens on the front.
Each student’s placement went beyond the typical recommendation of 6 feet of separation – instead there was 7 feet and 10 inches between each person. The model’s floor plan consisted of three rows of three desks with an instructor at the front corner.
“Aerosol distribution in the room is not uniform and is strongly influenced by air conditioning layout,” said the authors, from the University of New Mexico.
Based on the simulation, the authors suggest removing the middle seat to reduce potential spread. Students in the back corners received two to three times fewer particles on average than other students, so those may be better positions for students at risk for Covid-19 complications, the study said.
The authors said opening windows while the air conditioning was on increased the particles exiting the room and decreased particles deposited on those in the room.
The study emphasizes the need for “efficient filtering in the air conditioning systems.”
Ventilation from air conditioning systems reduces the number of particles in the air. However, since air flow is often recycled, the authors said particles exiting the classroom “may pose greater risk to individuals in other rooms.”
Even with only nine students and distance between them, aerosol “is transmitted in significant quantities between students and from one student other students’ desks,” the study said, highlighting the need for hand sanitization.
In the simulations, glass screens on desks reduced the spread of small particles from one student to another, and the authors said they should be used. But effectiveness will vary depending on air conditioning and the source of the aerosol.