The holes, dots, or stripes you see on N95 or KN95 masks are how manufacturers stick the layered materials together. This is what helps keep your mask in shape. The varying patterns you see across masks shouldn’t affect the masks’ ability to filter out viruses or other particles.
Our data shows that these areas may have a lower filtration efficiency, however the N95 and KN95 standards test the filtration efficiency of the entire mask. The entire mask, together, must filter out 95% of the target particles in order to be certified an N95 or KN95 mask.
“Dots” or “stripes” visible when holding KN95 masks up to the light
3M 1870 that has “dots”