The vast majority of SARS-CoV-2 transmission occurs indoors, most of it from the inhalation of airborne particles that contain the coronavirus.
I am a professor of mechanical engineering at the University of Colorado Boulder. Much of my work has focused on how to control the transmission of airborne infectious diseases indoors, and I’ve been asked by my own university, my kids’ schools and even the Alaska State Legislature for advice on how to make indoor spaces safe during this pandemic.
Thankfully, it can be pretty easy to get more outside air into a building. Keeping windows and doors open is a good start. Putting a box fan in a window blowing out can greatly increase air exchange too. In buildings that don’t have operable windows, you can change the mechanical ventilation system to increase how much air it is pumping.Using CO2 to measure air circulation So how do you know if the room you’re in has enough air exchange? It’s actually a pretty hard number to calculate.
When engineers improved air circulation and got CO2 levels under 600 ppm, the outbreak completely stopped. According to the research, the increase in ventilation was responsible for 97% of the decrease in transmission. The first thing to consider is how effective an air cleaner’s filter is. Your best option is a cleaner that uses a high-efficiency particulate air filter, as these remove more than 99.97% of all particle sizes.