Thanks for the links, replies and comments.

It sounds like for most situations, anything which restricts bad particles from reaching the respiratory system is certainly better than nothing, and the better the fit, the more that's inhibited. It's critical for the sick to at least try to prevent the spread of disease from the mouth & nose by wearing a mask.

I think I'll try adding a wire of band of some type to the top of the pad to get a better fit over the bridge of the nose, similar to many of the partial face masks with the tab over the nose.