You could start by adjusting your given filtration ratios by predictable leakage based on the type of mask. It's wholly misleading to rate the filtration potential of an earloop mask as equivalent to that of a 3M Aura.
For example an ASTM 2 or 3 surgical mask fabric has a filtration of 98%+
On my face I have a leakage of about 21% or PFE of 79% when worn normally.
With an ear saver, it jumps to 91%.
With a mask brace, it jumps to 98%.
So it really is about the fit.
If I put leakage % it would vary from person to person and many people would be mislead by this.
It measures the air outside the mask verses inside the mask.
https://tsi.com/products/respirator-fit-testers/portacount-r...
I get as low as 80% and as high as 99% on my face.
Fit is a big deal because it's personal and hard to communicate. I think it was Amazon that found when scanning their workforce that they discovered 29 different face shapes!
> With an ear saver, it jumps to 91%.
> With a mask brace, it jumps to 98%.
I had no idea it could vary so much for surgical masks. I’d be curious what range of leakage people could typically expect for other designs such boat-shaped KF94 or flat-fold KN95 masks.
Fit seems important enough to deserve a mention in the intro paragraph at the top of the home page. A more detailed explanation, including the example you gave of how much it can vary for even one person, could go in the “Click here” link to the full testing methodology.
Thank you for doing this, by the way, rare to see a manufacturer test so far beyond their own masks. It clearly takes resources to do this and is a great service to all of us who have been relying on guesswork.
For example I found this study on beard length which made me reconfigure my facial hair: https://www.nature.com/articles/s41370-021-00337-1
The charts in that paper also make it seem that n95 *typically* has a much better seal on the face which is worth noting.
I also wonder if the breathability you're measuring affects filtration, given imperfect fit. I would imagine that worse breathability would cause more air to flow around the mask rather than through it.