Surgical masks from Costco

 

My tests this month on some cheap "BYD Care" surgical masks from Costco UK. Box says 3-ply and a BFE of ≥ 98%.

Run 1: 59.2827%, ave so far: 59.2827%

Run 2: 53.3623%, ave so far: 56.3636%

Run 3: 53.5181%, ave so far: 55.4131%

Shitty nose wire of course. "Bread tidy" variety.

I added a second layer of stick-on nose wire - bulk purchased from amazon.

Run 1: 86.5944%, ave so far: 86.5944%

Run 2: 89.6312%, ave so far: 88.1128%

Run 3: 89.4828%, ave so far: 88.5714%

The I replaced the nose wire with one up-cycled mains flex from an electrical refit a couple of years ago:

Run 1: 94.8380%, ave so far: 94.8380%
Run 2: 95.1131%, ave so far: 94.9771%

Run 3: 94.4416%, ave so far: 94.8133%

All three masks pictured at the top. The "ports" are visible of course.

Nose wire replacement is a feature that should be built in to perhaps all masks

Wisconsin-Madison University mask fitter study

Strategies to minimize SARS-CoV-2 transmission in classroom settings: Combined impacts of ventilation and mask effective filtration efficiency

- December 31, 2020 

- David A. Rothamer, Scott Sanders, Douglas Reindl, and Timothy H. Bertram 

(all of University of Wisconsin-Madison)