FOCUS ON FACEMASKS / WHO NOW RECOMMENDS CLOTH MASKS FOR ALL
SNS Science News Story, May 31, 2020
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the full quote version of the story and art chart here
Fabrics Charge Up Filtering Efficiency of Cotton Used in Face Masks
Multiple layers of specific combinations of every-day fabrics were found to provide excellent filtration efficiency (FE), particularly when it came to the smallest aerosolized particles emitted during speech. The new study suggests that, in the right combination and layers, with no gapping around the perimeter, cloth face masks help reduce viral transmissions. The study was authored by scientists with the University of Chicago and Argonne National Laboratory in Lemont, Illinois.
The high-filtration rates of the top-performing samples, out of the 15 tested, were likely due to their combined effect of both mechanical and electrostatic-based barrier and filtration. This refers to the static electricity sometimes felt when handling polyester nits. "Polyester woven fabrics can retain more static charge compared to natural fibers or cotton due to their lower water adsorption [adherence to surface] properties," according to the study.
PARTICLES GO AIRBORNE AT UP TO 300 NM
WIDE FOR 10 MINUTES AND MORE
The researchers limited their study measurements to droplets sized from 10 to 10,000 nanometers (nm) wide, which is the respiratory virus transmission range. Droplets temporarily go airborne when particles are sized from 10 to 300 nm wide in diameter. Coronavirus particles are about 100 nm in diameter per image below.
To help relate, one millimeter is about half the side of a nickel—yet there are 1 million nanometers in a millimeter.
Time to reach for a face mask.