For 0.3-micron particles, Smart Air found “a much wider range in effectiveness.” The N95 mask, HEPA filter and surgical mask performed best, all capturing over 75% of small particles. But in terms of household materials, the best blockers were Hero-brand coffee filters. In the study, only four other materials filtered more than 48% of small particles: the 40D nylon, Chemex coffee filter, kitchen towel and canvas.
According to the study, “some materials were only slightly better than nothing.” The bandana, neck-warmer, scarves, cleaning cloths and 100% cotton T-shirt (one layer) all captured less than 10% of small particles.
Whichever material you choose to make your mask from, and no matter how you choose to make it ― for the most updated recommendations.