- An N95 mask filters out 95% of the particles that attempt to flow through the mask.
- An N99 mask filters out 99% of the particles that attempt to flow through the mask
- and an N100 mask filters out 100% of the particles that attempt to enter the mask.
- N means not resistant to oil.
- R means resistant to oil (there are also R95 masks available)
- and P means oil proof.
Please note that influenza viruses themselves are 0.08- 0.12 micrometers in diameter, smaller than what an N95 filter is capable of filtering. However, influenza viruses are often carried in aerosols of respiratory secretions, emitted from sneezing for example, that are up to 10 micrometers in diameter, large enough to be filtered out by an N95 mask.
Also note that not all N95 masks are NIOSH and FDA certified. Non-medical N95 masks may only be certified by NIOSH and not the FDA. Masks that are respirators and surgical masks are recommended since they meet standards of both NIOSH and the FDA. Here is a list of N95 mask models that meet NIOSH and FDA standards, listed by manufacturer. You can buy several N95 mask models from 3M and surgical masks from 3M, Dynarex and CVS online.
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