Good point.

When used against gas or biological weapons or all that other terrorist stuff certain people would have you believe is a risk, they're not effective. But they are effective at keeping particulates out of your face and lungs...even with a beard. Dust is the one thing I'm most worried about. If there's a bird flu pandemic, the mask will keep particulates out of my mouth...in addition to my hands.

Plus if anything serious were to happen, I always have the option to shave it off or tape it to my face.

I also keep a full face respirator filter mask in the garage for painting...it's big and keeps a positive seal.

If I were really worried, I'd buy a Scott Air Pack. I've been trained to use those and the beard is not an issue.