Here is the latest study on masks. No surprises here. It confirms what previous studies have shown. The only surprise is that the county judge continues to wear a bandana. The first is a summary from Journal Watch. Following is a link to the study from Science Advances.
Most efficacious face masks: N95, surgical, polypropylene, and handmade cotton face masks all appear efficacious for blocking respiratory droplets, while bandanas and fleeces seem to offer little protection, according to a study in Science Advances. Researchers tested the efficacy of 14 different mask types as follows: A male wearing each mask repeatedly spoke the words “Stay healthy, people” toward a laser beam inside a dark box. Droplets that passed through the laser scattered light, which was recorded with a cell phone camera, and a computer program then counted the droplets in the video. For reference, the speaker did the same while not wearing a mask. N95 masks were most efficacious, followed by surgical masks, then polypropylene masks and handmade cotton face coverings. Other masks were less efficacious. In particular, gaiter-type fleece coverings seemed to spread larger respiratory droplets into numerous smaller droplets. Of this, the researchers write, “Considering that smaller particles are airborne longer than large droplets … the use of such a mask might be counterproductive.”
https://advances.sciencemag.org/content/early/2020/08/07/sciadv.abd3083.full
