That's what you might call a Black Pill.
I've been self-isolated for decades, but it's time to make a grocery run. Wish me luck.
I've removed my air conditioner (hoping for a coat of white paint to get me through Summer. Currently, I've got a whole house fan that sucks (really well). I was going to put a furnace filter on an intake vent, but I noticed that the isolation wards the Commies threw up in Wuhan were overpressure.
I now have a b-day present on the way, a six-pack of
discountfilterstore.com/[14x14x1 Merv 11 Universal Air Filter By Tier1 (6-Pack)]. I will need to put a slide cassette between the whole-house fan and reverse it's flow (AC motor's orientation in the bracket).
Voila! Overpressure.