Table 2. The I/O ratios of the concentrations of suspended particulate matter in the surgical masks and N95 masks under without/with suction conditions.

	Surgical mask	N95 Mask	P value
Without suction
PM≥0.5,	0.80	1.34	0.173
PM10	0.82	1.37	0.116
PM2.5	0.82	1.37	0.117
PM1	0.82	1.37	0.117
With suction
PM≥0.5	1.18	1.36	0.602
PM10	1.11	1.26	0.465
PM2.5	1.11	1.26	0.465
PM1	1.10	1.26	0.465