Eight layers of chiffon - ragmask max

 Konda et al 2020 picked high thread count cotton and chiffon as a two later washable high filtration mask

Their chiffon wasn't what others thought was chiffon though.  One layer of chiffon is the purple line:

That's very detailed across a wide range of particle sizes.

Here's my reliable "Rag Mask Max" pattern sewn with EIGHT layers of regular chiffon

(PortaCount port in place)

Pattern

Results

July 06, 2022 20:50:51
Run 1: 90.7415%, ave so far: 90.7415%
Run 2: 91.2903%, ave so far: 91.0151%
Run 3: 90.8595%, ave so far: 90.9647%
Run 4: 91.2826%, ave so far: 91.0404%
Run 5: 91.1111%, ave so far: 91.0537%
Run 6: 90.8506%, ave so far: 91.0224%
Run 7: 91.5297%, ave so far: 91.0906%
Run 8: 92.2770%, ave so far: 91.2279%
Overall Average: 91.2279%
High: 92.2770%

Low: 90.7415%

Doesn't replicate the results of Konda et al 2020, I don't think.

Most likely it is the same filtration after washing, but why bother testing, 91.2% is too low for current Omicron variants.  Other than that the mask is super breathable, if a little hot in use. The chiffon will not get wet from your own exhaled breath - water vapor is going to evaporate as fast as it accumulates on polyesters like this.