and above contain far fewer virions than this theoretical maximum.
Filter media, such as those used in N95 masks and in mechanical ventilation systems, consist of myriad interwoven fibers through which air is moved. Their purpose is to arrest particles as they move through the matrix. Filters capture particles chiefly by three mechanisms: impaction, interception, and diffusion. Impaction occurs when the momentum of a particle propelled toward a filter fiber prevents the particle f