If you need dust protection (about P1) or an exhale filter (as per authority requirement) just print these out and attach any membrane material you have at hand, fasten with a wire and you are ready to go.
Made for a friend of mine who needs filters for his outdoor workers, since none are available for purchase these days (you couldn't guess why). Our government requires exhale filters as well, which makes the use of this standard piece of equipment rather cumbersome (ans, guess what, you can't really buy anything else today). So here you go.
Tested with 6300 (half mask) and 6900 (that fancy full mask with the big glass).
The author hasn't provided the model origin yet.