Table 2.

Thickness and air permeability of masks.

	Thickness (mm)	Air resistance (kPa.s/m)
Sample A	1.24	0.63
Sample B	1.00	0.28
Sample C	1.82	0.45
Sample D (without filter)	1.44	0.77
Sample D (with filter)	1.86	1.77
Sample E (without filter)	2.88	0.99
Sample E (with filter)	3.22	1.56
Sample F	1.08	0.32
Sample G (without filter)	0.98	0.06
Sample G (with filter)	2.42	0.61