Table 1.

Averaged filtration efficiency and pressure differences of single-layer and multi-layer materials tested in this study.

Materials	Averaged Filtration Efficiency	ΔP (Pa)
Cotton (Original / Washed)	87% / 85%	74.7
Non-woven Fabric (Fabric 1) (Original / Washed)	83% / 79%	29.9
Micro Fiber Cloth (Original / Washed)	83% / 83%	44.8
HVAC Filter	74.7%	64.8
Shower Curtain	74.4%	64.7
Vacuum Bag	95.2%	478.2
Surgical Mask	81.4%	378.6
Mask R95 (Original / Washed)	99% / 96%	169.4
Cotton – Cotton	91%	296.4
Cotton - HVAC	90%	211.7
Cotton – Fabric 1	91%	214.2
Cotton – Coffee Filter	91%	473
Cotton – Coffee Filter - Cotton	92%	548
Cotton – Coffee Filter – Fabric 1	91%	403.5