> to tell us that masks won't help because viruses are small It's actually 0.3 micrometer particles that are most difficult to filter. Smaller than that, parti

> to tell us that masks won't help because viruses are small It's actually 0.3 micrometer particles that are most difficult to filter. Smaller than that, particles start to dance around and not move smoothly, because of Brownian motion, so they get stuck in the filtering fibers better. https://www.researchgate.net/figure/Typical-filter-efficiency-as-a-function-of-particle-size-modified-from-Zevenhoven-and_fig8_266099381 https://www.researchgate.net/figure/Typical-filter-efficienc...