Why YSK: Back in 2020 when Australia had our massive wildfires I still had to drive to work everyday in the smoke. I also went and got my car serviced around the same time and they showed me how dark my cars air filters had gotten after just a few weeks of those conditions. The air filters in cars aren’t designed to filter out so many particles so as soon as you can you should get them replaced.
A fun fact about those furnace filters is that combined with your aver 20-22 inch box fan they’re a cheap way of getting very clean air in your house with a Corsi-Rosenthal box. https://cleanaircrew.org/box-fan-filters/