A report published by the American Chemical Society in ACS Nano that a combination of cotton with natural silk or chiffon can effectively filter out aerosol particles — if the fit is good.
One layer of a tightly woven cotton sheet, combined with two layers of polyester-spandex chiffon — a sheer fabric often used in evening gowns — filters 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.
Fabrics that hold a static charge, like certain types of chiffon and natural silk, serve as an electrostatic barrier.