[EvaH (OP)]

Zoltan asks:

With the coronavirus and the use of face masks, it is repeatedly stated that once a facemask is wet, it is no longer effective. However when a foam filter is used with an internal combustion engine, it is only effective when it is wet, with oil. As the holes in the foam are much larger than dust particles, the coating of oil on the foam will trap the dust particles instead of them bouncing around and working their way through to the engine. I would have thought that with virus particles also being much smaller than the holes in a facemask, the fibres in the mask being wet would also trap the virus particles instead of bouncing between fibres and working their way through. Or am I missing something?

Can you help?

[alancalverd]

The virus is transmitted in droplets. Any filter will eventually saturate if you add more liquid. Once the mask is palpably wet, you will be inhaling droplets from the mask. Not quite the same as a priming film of sticky oil that stays in the mask, unless the atmosphere is full of oil droplets .

[vhfpmr]

Wet fabric is substantially airtight, you can make quite an effective buoyancy aid from wet clothing filled with air.