U of M study measures how COVID-19 particles propagate in classrooms – WCCO

MINNEAPOLIS (WCCO) – While Minnesotans anxiously await Governor Tim Walz’s announcement about schools in the fall, a new study from the University of Minnesota has looked at how COVID-19 spreads indoors, especially in classrooms.

The experiment models the transmission of viruses in the air through aerosols that are expelled when people speak. The researchers measured how those aerosols land on nearby surfaces or are inhaled by someone else.

With the help of eight asymptomatic COVID-19 carriers, the researchers modeled how the virus traveled through the air in three interior spaces: an elevator, a classroom, and a supermarket.

After running a 50-minute simulation in a classroom with an asymptomatic teacher constantly talking, the researchers found that only 10% of their aerosols leaked. Most of the particles attached to the walls.

Credit: Suo Yang, University of Minnesota

“Because this is very strong ventilation, we thought it would expel a lot of aerosols. But, 10% is a really small number, ”said assistant professor Suo Yang. “Ventilation forms several circulation zones called vortices, but aerosols continue to rotate in this vortex. When they hit the wall, they stick to the wall. But because they are basically trapped in this vortex, and it is very difficult for them to get to the vent and really get out. “

However, the researchers were able to measure the virus’s “hot spots,” or places where aerosols tend to accumulate. His hope is to be able to avoid these common areas with the right combination of ventilation and interior design. For example, in the classroom, virus sprays spread less when the teacher is standing directly under a vent.

“This is the first quantitative risk assessment of spatial variation of risks in indoor environments,” said associate professor of mechanical engineering Jiarong Hong.

The information could inform how interior spaces are organized and disinfected. Researchers have recently collaborated with the Minnesota Orchestra to measure how aerosols travel while musicians perform at Orchestra Hall.