[mindslight]

If you're still making do with an ersatz cloth mask, sure. I've been wearing a P100 from the start of the pandemic. Both bowls of political Kool Aid are actively harmful - framing PPE as being about protecting others has also damaged the discourse.

Edit: also, I do agree that keeping stuff out of the air is preferable to filtering it after the fact (especially with mucous membranes etc). This concern is addressed somewhat by (3), and also by the additional point that Alice needs to demonstrate empathy of understanding and respecting Bob's choice as well.

[stirfish]

Where did you get your P100? Everywhere around me has been out of both those and oxygen tanks. It's made welding pretty difficult.

Edit: I appreciate your thorough and patient response to the parent comment.

[mindslight]

I had them before the pandemic, but I've seen them in stock quite regularly. Zoro appears to have my 3M 7503 half-face piece and 2297 filters in stock right now. For welding you might want a proper vapor filter though (60921?). 3M has some nice pdfs that list all the different options.

For pandemic usage when I need to filter my exhale, I disabled the check valves by popping the mask apart, removing all 3 valve flaps, and sealing up the output hole. This makes air flow through the filters bidirectionally. I've also seen a 3d-printed adapter for the 6100 series (I think) that attaches a third filter to the output. Separate input and output filters is probably a better way to go.

[stirfish]

Thank you. I'd never heard of zoro before, but I'll be depositing my paychecks here from now on. It looks a lot more fun than the bank :)

[mindslight]

Haha, yes it is. They're the customer-facing brand of Grainger so they've got everything. Their search is okay and some of their product data can be lacking, but their selection is massive. As I alluded to, it's often worth it to go find the manufacturer's pdf catalog and then search by part numbers.