A Quantitative Assessment of the Total Inward Leakage of NaCl Aerosol Representing Submicron-Size Bioaerosol Through N95 Filtering Facepiece Respirators and Surgical Masks

Figures & data

Figure 1 Flow diagram of the manikin experimental setup used for submicron-size particle leakage under simulated breathing conditions (The rubber bladder mimics a human lung and allows breathing air to enter and exit through the mouth. A typical FFR with a sample probe and one leak probe is shown in the inset. The differential mobility analyzer (DMA) of the SMPS separates particles based on their electrical mobility.) (color figure available online)

Table 1 Filter Penetration for the N95 FFR Models and SM Models at 85 L/min Constant Flow (Average of three samples (n = 3), error represents one standard deviation.)

	Filter Penetration (%)
Penetration Method	N1	N2	SM1	SM2
NaCl aerosol (CMD 75 ± 20 nm) (TSI 8130 – photometric, Constant flow - 85 L/min)	0.17 ± 0.06	0.86 ± 0.22	1.58 ± 0.25	88.1 ± 0.81

Table 2 Comparison of Total Inward Leakage (TIL) at Two Different Breathing Minute Volumes and Three Leak Sizes (Average of 4 samples (n = 4), error represents one standard deviation.)

		TIL (%)
		Particle Size (nm)
		N1		N2		SM1		SM2
Leak Size	Breathing Minute	______________________		______________________		______________________		_____________________
(mm)	Volume (L/min)	45	300	45	300	45	300	45	300
No Leaks	8	0.31±0.4	0.12±0.1	1.48±2.1	1.01±0.3	3.58±1.5	2.91±1.5	45.08±20	87.55±28
	40	1.56±0.9	0.31±0.2	4.96±2.9	2.55±1.9	9.33±2.4	2.27±2.1	68.44±14	96.59±10
Two 3 mm	8	10.67±4.6	9.94±3.1	11.52±7.7	10.14±1.6	14.76±5.1	9.70±10.3	67.01±7.0	100.03±95
	40	8.56±3.1	8.45±2.4	11.75±4.6	9.14±1.6	14.02±3.8	9.25±3.95	71.57±6.1	99.78±5.2
Four 3 mm	8	30.54±4.2	28.48±2.5	30.66±6.3	29.26±3.9	28.15±3.8	27.56±5.3	66.65±7.5	99.21±11
	40	29.5±3.6	27.53±2.6	27.86±3.2	24.42±3.5	25.62±6.4	25.06±4.7	70.54±10	104.38±12
Six 3 mm	8	38.72±5.7	39.87±4.8	36.22±7.3	37.18±3.7	35.67±6.3	33.53±7.2	52.92±16	95.52±16
	40	31.45±3.4	32.58±4.9	36.96±4.0	35.83±3.4	37.37±4.6	36.40±3.6	72.12±9.5	93.47±7.5

Figure 2 Typical TIL values for the two N95 FFR models N1 and N2 at 8 L/min (left column) and 40 L/min (right column) breathing minute volumes (The symbols indicate sealed with no leaks (•), two 1.18 mm leaks (○), and two 1.80 mm leaks (▾). The solid vertical line corresponds to the approximate MPPS (45 nm) of the two N95 FFR models. The dashed vertical line corresponds to the mode of the challenge aerosol (75 nm).)

Figure 3 Typical TIL values for the two N95 FFR models N1 and N2 at 8 L/min (left column) and 40 L/min (right column) breathing minute volumes (The symbols indicate: sealed with no leaks (•), two 3 mm leaks (○), four 3 mm leaks (▾), and six 3 mm leaks (Δ). The solid vertical line corresponds to the approximate MPPS (45 nm) of the two N95 FFR models. The dashed vertical line corresponds to the mode of the challenge aerosol [75 nm]).

Figure 4 Typical TIL values for the two surgical models SM1 and SM2 at 8 L/min (left column) and 40 L/min (right column) breathing minute volume (The symbols indicate: sealed with no leaks (•), two 3 mm leaks (○), four 3 mm leaks (▾), and six 3 mm leaks (▵). The solid vertical line corresponds to the MPPS of ∼45 nm for SM1 and ∼350 nm for SM2 models. The dashed vertical line corresponds to the mode of the challenge aerosol [75 nm]).