[Equipment] What are the strengths + weaknesses of Surgically Masking over CPAP devices' air inle

[StackExchange]

Many patients go the extra mile/mask! See picture above. In addition to the CPAP filter that they use and replace regularly,  they mask over their CPAP machine's air intake, with a Surgical Mask that they replace regularly. They have "gone the extra mask" like this for years, without incident, for 2 reasons.

1. Some want to save money, by replacing CPAP filters more sparingly, without adverse effect]https://en.wikipedia.org/wiki/Adverse_effect]adverse effect. They reckon that a surgical mask can defend against particulates as a first layer that shall lessen the amount of particulates to be filtered by the CPAP filter, therefore shall lengthen each CPAP filter's lifespan

What are the reasons FOR + AGAINST "going the extra surgical mask" like this?

[Sleeprider]

I fixed this post by editing out the code tag that prevented the formatting from showing.

Using a mask over the CPAP air inlet filter opening looks like it might provide a pre-filter. I don't see any problem with this idea and might help in a particularly dusty location. I don't know, but it may also filter pollen or allergens from entering the machine.

[quiescence at last]

consider it, but realize:
a. surgical masks, like other types, do not work well when you do not seal them properly against a face (or some fake simile).
b. surgical mask are meant to be a barrier staff uses to reduce the risk of staff's breathing or coughing, etc. from propelling germs to the patient (in surgery).
c. they can be partially protective from floating aerosol of someone else's cough, sneeze, exhales.  this sort of barrier use is similar to using a face shield or sneeze shield between you (your machine inlet) and others.

d. Any use of second filtering product that does fit tightly will tend to increase strain and increase noise of the machine.

e. viral protection relies on the virus not being able to proceed through the barrier, and that usually mean really affecting the amount of air flow allowed, and need for a stronger fan in the machine, or an entrance that has a suitably large surface area to get the required flow rate.

f. UV radiation is way more effective because it damages (kills) the virus.  In that case the virus needs to be illuminated for the better part of 2 seconds.  That is also only possible by slowing the virus down so it gets the effective amount of light.  This is another big box of air at low flow rates or high intensity light problem.  UV is not that great for the eyes and skin.

My only suggestion is to make sure you have a dense filter (not just the foam filter), compare the noise it makes, then add another filter of that type. if it makes too much noise, back it off to just one.  You could also fabricate a filter out of HEPA filter material and seal the edges - try this instead of or in concert with the white dense filter, checking for noise generation difference.

ps. How effective HEPA filters are against COVID - I was surprised by this article regarding removing COVID from the air.
  
QAL