TABLE 2

Mean values of the reduction factors, fit factor, required minimum efficiency and assigned protection factor for the grouped range of filtering facepieces and surgical masks [36]

Mask type	Reduction factor		Fit factor		Required minimum filter efficiency %	Assigned protection factor
	Ambient particles	Simulated sneeze	Ambient particles	Simulated sneeze	Required minimum filter efficiency %	Assigned protection factor
FFP3	228	145	766	167	99	20
FFP2	95	54	258	52	94	10
FFP1	29	42	1791	335	80	4
Surgical mask – tie	4	2	4	2	Unknown	Unknown
Surgical mask – strap	5	2	9	2	Unknown	Unknown
Surgical mask – all	4	2	5	2	Unknown	Unknown