oldhippydude
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https://www.sciencedaily.com/releases/2020/04/200424081648.htm
The researchers used an aerosol mixing chamber to produce particles ranging from 10 nm to 6 μm in diameter. A fan blew the aerosol across various cloth samples at an airflow rate corresponding to a person's respiration at rest, and the team measured the number and size of particles in air before and after passing through the fabric. One layer of a tightly woven cotton sheet combined with two layers of polyester-spandex chiffon -- a sheer fabric often used in evening gowns -- filtered out the most aerosol particles (80-99%, depending on particle size), with performance close to that of an N95 mask material. Substituting the chiffon with natural silk or flannel, or simply using a cotton quilt with cotton-polyester batting, produced similar results. The researchers point out that tightly woven fabrics, such as cotton, can act as a mechanical barrier to particles, whereas fabrics that hold a static charge, like certain types of chiffon and natural silk, serve as an electrostatic barrier. However, a 1% gap reduced the filtering efficiency of all masks by half or more, emphasizing the importance of a properly fitted mask.
The researchers used an aerosol mixing chamber to produce particles ranging from 10 nm to 6 μm in diameter. A fan blew the aerosol across various cloth samples at an airflow rate corresponding to a person's respiration at rest, and the team measured the number and size of particles in air before and after passing through the fabric. One layer of a tightly woven cotton sheet combined with two layers of polyester-spandex chiffon -- a sheer fabric often used in evening gowns -- filtered out the most aerosol particles (80-99%, depending on particle size), with performance close to that of an N95 mask material. Substituting the chiffon with natural silk or flannel, or simply using a cotton quilt with cotton-polyester batting, produced similar results. The researchers point out that tightly woven fabrics, such as cotton, can act as a mechanical barrier to particles, whereas fabrics that hold a static charge, like certain types of chiffon and natural silk, serve as an electrostatic barrier. However, a 1% gap reduced the filtering efficiency of all masks by half or more, emphasizing the importance of a properly fitted mask.
