Build a Do-It-Yourself Air Purifier for About $40
Michigan Medicine · 3:39 · Watch on YouTube
A $25-$30 DIY box fan with a 20x20-inch MERV 13 furnace filter removes ~90% of 0.3-micron airborne particles, while an $800 HEPA unit scrubs counts from ~400,000 to near zero, making bedroom filtration an effective wa...