Why can't you use HEPA material to make masks?

[PastTense]

There is a New York Times article:
What’s the Best Material for a Mask?

In recent tests, HEPA furnace filters scored well, as did vacuum cleaner bags, layers of 600-count pillowcases and fabric similar to flannel pajamas…

The best medical mask — called the N95 respirator — filters out at least 95 percent of particles as small as 0.3 microns. By comparison, a typical surgical mask — made using a rectangular piece of pleated fabric with elastic ear loops — has a filtration efficiency ranging from 60 to 80 percent.

Dr. Wang’s group tested two types of air filters. An allergy-reduction HVAC filter worked the best, capturing 89 percent of particles with one layer and 94 percent with two layers. A furnace filter captured 75 percent with two layers, but required six layers to achieve 95 percent…

The problem with air filters is that they potentially could shed small fibers that would be risky to inhale. So if you want to use a filter, you need to sandwich the filter between two layers of cotton fabric.

What’s the Best Material for a Mask?