N95 respirator masks, what you should know

N95 Respirator

Searching the inter-webs regarding the ongoing Ebola incidents will inevitably lead you to an online advertisement for a respirator or face mask of some type.  One of the most common respirators is the N95. These masks are a cheap and effective way of increasing your ability to filter out small pathogen particles.

I’ve read several articles comparing the N95 face mask to other sealed face masks.  If given the choice I would much rather wear a fully sealed full face respirator, that isn’t always practical.  I read a study by CIDRAP-Center for Infectious  Disease Research and Policy at University of Minnesota.  The study support the use of N95 respirator face masks as a means of increasing your personal protection against the Swine flu viruses.  The Swine Flu virus size is approximately 80 - 120 nanometres in diameter.  In comparison the Ebola virus is approximately 80nm in diameter.  The study went on to say that properly fitted N95 respirators stopped 99.8% of the Swine flu virus transmissions during this test -reference.

Loose fitting masks, deformed / crushed, dirty, or wet  face masks will have a markedly decreased ability to block particles.  There are several reasons an N95 mask might be worn.  One reason is to keep an infected persons particles contained within the mask.  We know that sneezing, coughing, vomiting, laughing, brushing teeth, and many other acts will cause particles to be Aerosolized.  Aerosolization is when a particle is small enough and light enough that the particle is suspended in and carried by the air currents.  Aerosolization can be naturally occurring or man made.  Wearing a properly fitting N95 respirator can help contain those infectious small particles.  Ensure that when using an N95 mask as an isolation device, use only a masks without an exhaust valve.  

N95 Respirator with exhaust port

An exhaust valve is placed on some N95 respirator masks to increase the volume of air that exits the mask.  This exhaust valve also helps decrease fluid build up on the inside of the mask from condensation, which can lead to the mask losing viability more quickly.  A mask with an exhaust valve will do nothing to isolate a person who may be infected, the exhaust is not filtered by the mask and is directed right into the air.  Use a non-exhaust valve N95 mask for isolation.

We know from a previous article that viruses are so small that when aerosolization occurs the particles can be suspended in the air for many hours, the smaller particles which are suspended for extended amount of time are considered airborne. The N95 respirator is shown to provide personal protection against airborne infectious particle such as viruses and bacteria.  Face mask type respirators are not an airtight seal which means there is still chance for particles sufficiently small to make their way into the users respiratory system even when wearing an N95 mask.

Using a full face - sealed respirator such as the FM50, or other sealed respirators will provide much more enhanced protection than what the N95 can provide.  
 

Things to look for to ensure you are getting a certified N95 mask: Each mask should have National Institute for Occupational Safety and Health - NIOSH-approved stamped on the front of the respirator.  


The N95 name comes from the NIOSH certification process which requires a mask meeting N95 approval to be able to filter out 95% of airborne particulates. Within the N95 family there are several other variants.  One N95 respirator is referred to as a “Surgical N95 Respirator”.  A “Surgical N95 Respirator” has an enhanced fluid and flammability resistance requirement. The fluid resistance is not against oil based fluids, rather the mask is resistant to exposure of bodily fluids while still remaining a viable filtration medium.  N95 masks are designed to be single use.  


N95 masks are not intended to be reused over multiple engagements.  One of the risks when reusing any type of protective equipment is the chance of cross contamination.  The filtration process that takes place within the N95 mask uses gravity, impaction, and diffusion methods to entrap the particles in the filter media.  The filter media itself is now a point of contamination.  Proper handling should be used when removing the face mask to ensure the user is not exposed to the particles trapped within the mask media. 


A used mask is now a fomite or an object that is capable of carrying infectious organisms and spreading them to others. Dispose of used face masks with caution and do not allow anyone to come in contact with the used face mask as they are at a high risk from contamination. 


Ensure that N95 respirators are replaced with a new respirator when unit has become visibly dirty, resistance in air flow is detected, the mask become wet, the mask is exposed to oil based particles, the mask has been used 8 or more hours in a high particulate area.


How to perform a user seal check on an N95 respirator mask