How
does the surgical N95 respirator mask by 3M stop the SARS-CoV-2 virus from accessing the airway
passages of the wearer?
Coronavirus
virions are spherical with diameters of approximately 125 nm. Where
an ‘nm’, indicates a nanometer which is a billionth of a meter.
The
indicated mask is documented to have a filter efficiency level of at least 95% against particulate aerosols free of oil and was
tested against a 0.3 micron (0.0000003 meter) particle (mass median aerodynamic
diameter). Where a micron is one millionth of a meter.
Given
above facts where the virion (0.000000125 meter) is 2.4 times smaller
than the mask’s preventive ‘entry’ capacity of 0.0000003 meter, one may wonder is
it not going to go through?
Answer:
viruses do not fly through the air all by themselves, rather they are carried in
the aerosol particles expelled from the infected with or carrier person of the
virus. This originates from the coughing or sneezing process. And since aerosols
seem to average at 1.25 microns
(0.00000125 meter), which is larger than the 0.3 micron above, therefore the virus
conveying aerosol should be stopped by the mask.
Notably
here, the aerosols with its virions lodge in the outside of the mask and
therefore the wearer should avoid touching the outward surface of the mask.
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