> Viruses are generally too small for even the best filters... The average diameter of coronavirus particles is around 0.12 μm. The diameter of the envelope is

> Viruses are generally too small for even the best filters... The average diameter of coronavirus particles is around 0.12 μm. The diameter of the envelope is 0.08 μm and the spikes are 0.02 μm long. A P100 HEPA filter will remove as much as 99.97% (for P95 it is 95%) of all airborne particulates with an aerodynamic diameter of 0.3 μm, and particles both larger and smaller are removed with an efficiency greater than 99.97%. Even if viruses are smaller than 0.3 μm, they are an easy target for HEPA filters.