Also known as a Corsi-Rosenthal box, this DIY method of building your own air filter with MERV13 furnace filters and a box fan are an easy and cost-effective way to help clear indoor air from airborne virus particles, wildfire smoke, pollen, dust, and more! If you can seal a box, you can build one (or
I built one on these last night, thanks for the tip! It’s nasty here in Pennsylvania, and my daughters were coughing a lot.