As I understand it FFPn masks are designed and tested to protect the
wearer.

There are at least two variants - ones with an exhaust valve and ones
without.

If you take the WHO advice to wear at least FFP2 or equivalent then you
should be (at lest somewhat) protected against Covid19.
The vented models don't protect anyone else.

The unvented models presumably protect others as well, by filtering the
exhaling, but are they tested for this?
Then again, I assume that they should be at least as effective as the home
made cloth masks.

Sensible options seem to be to wear an unvented mask, or wear a vented
mask with a cloth mask over the top.

Two more questions.

(1) FFPn masks are usually used (at least by DIYers) to filter dust and
other particulates when using power tools and the like which generate dust.
How long should one use a disposable mask before disposing?

Shortest time might be drilling one hole in a wall or a quick belt (!)
with a sander. This seems a waste of a mask if it is discarded after just
a couple of minutes use.

Longest time might be "I replace it every January if it needs it or not.".
There must be a point where the filter has given of its best and is
clogged.

No apply this to an FFP2 mask used for shopping.
Pop into the Chemist for two minutes, then discard?
Seems wasteful.

Use for all of shopping day?

Use for a week then swap?

To me a difficult question because I don't know the risk of contamination
by first use spreading to the filter. In any case both vented and unvented
are filtering the incoming air in the same way (presumably) so the vent
should not be an issue for this calculation.
However the unvented stores your own exhalation as well, which might
encourage viral growth via moisture.
Unless of course you are double masking with a washable or disposable mask
and a vented mask.

(2) How do you find a reliable supplier?
If you use Amazon then you are usually safe using Amazon own product, but
less so using Marketplace.
Using eBay or etsy and you seem to be on your own.
Well known high street names don't seem to have any face masks in stock.
Screwfix stocks an FFP2 mask but that is vented.


So many questions, so little time!

Cheers




Dave R


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