These were sealed shut onto the test equipment using wax (ie: perfect fitment, so best case scenario). They found a much higher penetration through the materials per se for cloth coverings and procedure masks.
> Particle penetration through the surgical mask ranged from 2% to 17%. Procedure masks were most variable and ranged from 1% to 85%
> For the six cloth face coverings, the submicron particle penetration ranged from 24% to 92%. For the two types of fabric from cotton t-shirts, submicron particle penetration ranged from 45% to 91%. Although this sample size was small, these penetration percentages for the cloth face coverings and fabric from cotton t-shirts are comparable to the 40% to 90% penetration found by previous NIOSH testing of cloth face coverings and fabrics.
For the respirators with exhalation valves their finding was the particle penetration was <1% to 55% without any additional mitigation and under 5% when using the ECG pad mitigation strategy tested. Relevant since a common earlier critique (perhaps assumption) of valved respirators was they weren't as decent as even common masks for non-wearers.
[1] https://www.cdc.gov/niosh/docs/2021-107/pdfs/2021-107.pdf