curated by Marilyn M. Singleton, M.D., J.D. Transmission of SARS-CoV-2 Note: A COVID-19 (SARS-CoV-2) particle is 0.125 micrometers (μm); influenza virus size is 0.08 – 0.12 μm; a human hair is about 150 μm. *1 nm = 0.001 micron; 1000 nm = 1 micron; Micrometer (μm) is the preferred name for micron (an older term) […] //

Conclusion: Wearing masks will not reduce SARS-CoV-2.
N95 masks protect health care workers, but are not recommended for source control transmission.
Surgical masks are better than cloth but not very efficient at preventing emissions from infected patients.
Cloth masks will be ineffective at preventing SARS-CoV-2 transmission, whether worn as source control or as personal protective equipment (PPE).
“Masks may confuse that message and give people a false sense of security. If masks had been the solution in Asia, shouldn’t they have stopped the pandemic before it spread elsewhere?” //

Advice to decision makers on the use of masks for healthy people in community settings

As described above, the wide use of masks by healthy people in the community setting is not supported by current evidence and carries uncertainties and critical risks.”