Cloth face mask fit and function for children part two: Material Selection

The second component of this three-paper series studying cloth face masks for children ages 4 to 6 years old concentrates on optimizing aerosol capture and air permeability through fabric selection. Material choices were evaluated in two modes: Flat Filter (FF) and Head Form (HF). FF isolates material factors while HF simulates the performance of the constructed masks on a 3D printed child head form. In FF mode, higher filtration efficiency correlated to lower air permeability in both reusable commercial and experimental face masks regardless of fiber contents, fabric structures, and number of layers. Our prototype face mask developed in design exploration successfully captured 37 ± 12% of 0.3 μm, 87 ± 3% of 0.5 μm, and 87 ± 2% of 1.0 μm particles while maintaining good air permeability, moisture capture, and aerosolized salt capture in HF mode. Sealing masks to minimize outward leakage reduced particle capture up to 64%. Particle leakage data captured at the eye level of the head form illuminated the synergy between mask design, material choice, and fit.