Science | March 8, 2022 6:00 am

Air Filtration Is Critical to COVID-19 Safety. One DIY System Could Help.

They can be made for under $100

Corsi-Rosenthal box
A homemade Corsi-Rosenthal box.
Festucarubra, CC BY-SA 4.0

As the United States enters a third year of living with COVID-19 — and many states begin to treat it as endemic rather than pandemic — a debate has begun over what lessons can be learned from the last few years and how they can be applied to public health. Among them is a growing recognition of the importance of air filtration systems, especially in indoor spaces.

A recent article by Saahil Desai at The Atlantic, for instance, pondered whether the coming months and years would see restaurants taking steps to improve their air filtration capacities. “At every turn, Americans have failed to grasp just how much indoor air matters for this pandemic,” Desai wrote. “HEPA filters would be in every restaurant already if that’s what customers truly wanted, or if governments required them.”

State-of-the-art air filters aren’t the only way indoor air can be made safer. A recent article by Douglas Hannah at Smithsonian Maagzine explored the flexibility of the Corsi-Rosenthal box, a kind of DIY air filter that can be assembled quickly — but which can also make the air in an indoor space a lot cleaner.

Hannah describes the system as “a cube consisting of four to five off-the-shelf furnace filters topped by a standard box fan blowing outward.” It costs less than $100 to get the materials for one, and they can be built in under an hour. The article describes the kinds of spaces where Corsi-Rosenthal boxes have proven useful — homeless shelters, classrooms and day care centers among them.

Studies suggest that these boxes can both augment existing air filtration systems and do a solid job on their own. It’s welcome news for those seeking an easy-to-implement measure to make indoor spaces safer.