Our paper on mask filtration is out!
And it's #OpenAccess.
Filtration Performance of Layering Masks and Face Coverings and the Reusability of Cotton Masks after Repeated Washing and Drying.
aaqr.org/articles/aaqr-…
And it's #OpenAccess.
Filtration Performance of Layering Masks and Face Coverings and the Reusability of Cotton Masks after Repeated Washing and Drying.
aaqr.org/articles/aaqr-…
Two key results from this paper:
1. Doubling up a cloth mask over a surgical mask works better than using just one mask, EXCEPT if the surgical mask has an electrostatic layer.
If you are using an electrostatic mask, there is no point adding a cloth mask over it.
If you are using an electrostatic mask, there is no point adding a cloth mask over it.
2. You know that cotton mask that you have been washing, drying and reusing for over a year now? It's probably still fine! Don't throw it away.
We saw a bit of an increase in inhalation resistance, but no change in filtration efficiency after 52 wash/dry cycles.
We saw a bit of an increase in inhalation resistance, but no change in filtration efficiency after 52 wash/dry cycles.
Two very important caveats: We only looked at inward filtration efficiency (protecting the receptor, not reducing transmission from the source) and assuming a perfect fit condition.
As many other papers have shown, even though cloth masks have a low filtration efficiency at 300 nm, they are still good to protect others in case the wearer is contagious.
And they can protect the wearer from larger and smaller particles, provided that the fit is good.
This work was part of a wonderful collaboration with @NREL scientists.
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