In honor of the first day of school in Michigan tomorrow, I wanted to bring attention to an article in the Wall Street Journal that reinforces an important concept for COVID-19 safety in classrooms. It is that by simply increasing ventilation and airflow in classrooms, respiratory clouds that contain the SARS-CoV-2 virus can be disrupted before they can cause infection.
It is a concept that seems to have been somewhat forgotten about in the return to school.
Most recommendations focused on social distancing and surface decontamination. No one really thought about how to keep people safe when they had to be in groups. Scientists and mechanical engineers have recently issuing recommendations to schools and businesses that wish to reopen for how often indoor air needs to be replaced, as well as guidelines for the fans, filters and other equipment needed to meet the goals.
This concept is being driven by research findings that suggest that most coronavirus transmission is the airborne aerosols. In fact, focusing on masks and air flow are clearly the most important things in preventing transmission of COVID-19.
Most experts now suggest that public spaces, like standard classrooms, should have air replaced with clean air between four to six times an hour to dilute Covid-19 particles that might be coughed or breathed into the air.
That can be done, aerosol scientists say, through strategies that introduce outdoor air and filter indoor contaminants. Those include opening windows and doors, installing window fans, using portable air purifiers with high-efficiency particulate air, or HEPA, filters and upgrading heating, ventilation, and air-conditioning systems to meet standards.
As winter comes to the northern states, heating units and portable HEPA filters will become crucial to maintaining airflow given that outside air cannot be freely exchanged (at least without frostbite). While HEPA air filters are not inexpensive, they are cheaper than hospitalizations and would be a great alternative to leaving working parents in the lurch!