MINNEOPOLIS (WCCO) – As Minnesota states anxiously await Gov. Tim Walsh’s announcement of schools in the fall, a new University of Minnesota study looked at how COVID-19 is spreading indoors, especially in classrooms.
The experiment simulates the transmission of the virus in the air through aerosols that are emitted when people talk. The researchers measured how these aerosols landed on adjacent surfaces or were inhaled by another person.
Using eight asymptomatic COVID-19 carriers, the researchers simulated how the virus traveled through the air in three rooms: an elevator, a classroom and a supermarket.
After running a 50-minute simulation in a classroom with an asymptomatic teacher talking constantly, the researchers found that only 10% of their aerosols were filtered. Most particles are attached to the walls.
“Because it’s very strong ventilation, we thought it would ventilate a lot of aerosols. But 10% is a really small amount, “said Associate Professor Su Yang. “Ventilation forms several circulation zones called vortices, but aerosols continue to rotate in that vortex. When they touch the wall, they attach to the wall. But because they mostly get into this vortex, and it’s very difficult for them to get to the vent and actually go outside. “
However, the researchers were able to measure the “hot spots” of the virus, or places where aerosols usually collect. They hope to be able to avoid these common areas with the right combination of ventilation and interior design. For example, in a lesson, aerosols of viruses were less common when the teacher was standing directly under the vent.
“This is the first quantitative assessment of the risk of spatial changes in indoor risks,” said Jarong Gong, an associate professor of mechanical engineering.
This inspection can tell you how the interior is arranged and disinfected. Researchers recently collaborated with the Minnesota Orchestra to measure how aerosols travel while musicians perform in the Orchestra Hall.