I've been looking at Keffiyehs, and they look very comfortable. I figure one of those with an rz filter tucked in would work wonders.

A question for all those who have used these masks: Is the mask itself essential to the filtration, or is it the filter that does the majority of the filtration? I ask because the filters are much less expensive, and I like the idea of making my own mask-contraption and using their filters better. I...