Seriously, Upgrade Your Face Mask

[Ms. Toad]

20. Cloth masks ar not all equal.

Well-fitted 600 TPI cotton filter as well as K/N 95 masks when new (95-98%). Two-layer quilter's cotton (fewer than 600 TPI) with a third layer of a different fabric like silk also work as well as K/N 95 masks.

Both cloth and disposable masis degrade over time. K/N95 drop to around 85% after about 30 hours. Cloth masks degrade with washing (think lint on the lint filter), but the speed of degradation is more is more variable with cloth.

https://pubs.acs.org/doi/pdf/10.1021/acsnano.0c03252 (Table 1, middle of the page for 600 TPI; Hybrid 2 (3 lines p from the bottom); cf N95 with no gap (top line) for particles >300nm (the size at which filtration is measured)

Fit and filtration are key. Surgical mask - in general - do not fit. Air takes the path of least resistance - so if you have gaps, regardless of filtration level, it's a bad mask. Surgical masks with a gap filter 44% of particles of the applicable size - and I have not yet seen a surgical mask that does not gap.