https://pubmed.ncbi.nlm.nih.gov/16490606/
Conclusion: The N95 filtering face piece respirators may not provide the expected protection level against small virions. Some surgical masks may let a significant fraction of airborne viruses penetrate through their filters, providing very low protection against aerosolized infectious agents in the size range of 10 to 80 nm
The SARS-CoV-2 virus is only about 100 nanometers in diameter. The holes in your standard cloth or surgical mask are much larger than the size of a coronavirus.
https://pubmed.ncbi.nlm.nih.gov/16490606/ Conclusion: The N95 filtering face piece respirators may not provide the expected protection level against small virions. Some surgical masks may let a significant fraction of airborne viruses penetrate through their filters, providing very low protection against aerosolized infectious agents in the size range of 10 to 80 nm
The SARS-CoV-2 virus is only about 100 nanometers in diameter. The holes in your standard cloth or surgical mask are much larger than the size of a coronavirus.