Informing Homemade Emergency Facemask Design: The Ability of Common Fabrics to Filter Ultrafine Particles

Objectives: To examine the ability of fabrics which might be used to create homemade face masks to filter out ultrafine (smaller than 1μm in diameter) particles. Method: Twenty commonly available fabrics and materials were evaluated for their ability to reduce air concentrations of ultrafine particles. Further assessment was made on the filtration ability of select fabrics while damp and of fabric combinations which might be used to construct homemade masks. Results: Single fabric layers blocked a range of ultrafine particles. When fabrics were layered, significantly more ultrafine particles were filtered. Several fabric combinations were successful in removing similar amounts of ultrafine particles when compared to an N95 mask and surgical mask. Conclusions: The current coronavirus pandemic has left many communities without access to commercial facemasks. Our findings suggest that face masks made from layered common fabric can help filter ultrafine particles and provide some protection for the wearer when commercial facemasks are unavailable.