Size-Resolved Penetration Through High-Efficiency Filter Media Typically Used for Aerosol Sampling

Figures & data

TABLE 1 The list of measured filters and their porosity and DOP values (as available from manufacturers)

Code	Note	Product number	Porosity [%]	DOP [%]	Pore size [μm]	Thickness [μm]
M_Q_AQFA		AQFA04700		0.002		430
W_Q_QM-A_I		QM-A 1851-047		0.05
W_Q_QM-A_II		QM-A 1851-047		0.05
P_Q_QAT	Tissuquartz	2500 QAT-UP		0.10		432
M_G_APFA		APFA04700	90	0.002		230
W_G_GF/C_I		GF/C 1822-047				260
W_G_GF/C_II		GF/C 1822-047				260
W_G_GF/A		GF/A 1820-047				260
W_G_EPM	Cleaned	EPM 2000				450
M_MCE_SSWP_I		SSWP04700	83		3	150
M_MCE_SSWP_II		SSWP04700	83		3	150
M_MCE_RAWP		RAWP04700	82		1.2	150
W_PC_N0.4	Nuclepore 0.4 μm	111107	<15		0.4	6-11
W_PC_N8	Nuclepore 8 μm	111114	<15		4	6-11
P_PTFE_T1	Teflo 1 μm	R2PL047		0.01
P_PTFE_T3_I	Teflo 3 μm	60146		0.21	3	30.4
P_PTFE_T3_II	Teflo 3 μm	60146		0.21	3	30.4
P_PTFE_Z2	Zefluor 2 μm	P5PJ047		0.01	2	178
P_PTFE_Z2_1m	Zefluor 2 μm, 16.7 lpm	P5PJ047
P_PTFE_Z2_8lpm	Zefluor 2 μm, 8.3 lpm	P5PJ047

Codes of the filters are in the form of Manufacturer_FilterType_Name. In manufacturer, M denotes Millipore, W denotes Whatman, and P denotes Pall. In the filter type, Q stands for quartz fiber, G for glass fiber, MCE for mixed cellulose esters, PTFE for Polytetrafluoroethylene, and PC for polycarbonate. Two different batch numbers were measured for some filters. If that is the case, there is an I or II at the end of the name. The DOP values were provided for 32 lpm.

FIG. 1. The schematics of the filter tester used in this study.

FIG. 2. Size-resolved penetration of submicron particles challenging the filter media.

TABLE 2 Maxima of penetration, MPPS and fit widths, and pressure drops (at the face velocity of 40 cm/s) for all measured filters

Code	Penetration maximum [%]	MPPS [nm]	Fit width	Pressure drop [kPa]
W_G_EPM	2.80E-03	86.1	0.71	2.4
W_G_GF/C_I	3.50E-03	36.4	2.59	8.0
W_G_GF/C_II	3.60E-03	51.3	0.23	7.5
W_Q_QM-A_I	5.72E-02	59.3	0.82	6.0
W_G_GF/A	6.74E-02	78.8	0.56	1.7
M_G_APFA	1.45E-01	48.7	0.82	4.9
M_MCE_RAWP	1.50E-01	53.5	0.60	9.7
M_Q_AQFA	1.79E-01	60.3	0.75	4.9
M_MCE_SSWP_II	2.04E-01	62.9	0.55	8.5
M_MCE_SSWP_I	2.51E-01	55.0	0.49	9.0
P_Q_QAT	5.80E-01	68.0	0.64	3.6
P_PTFE_Z2	3.69E+00	20.0	—	4.1
P_PTFE_T3_I	7.98E+00	20.0	—	1.6
P_PTFE_T3_II	8.12E+00	29.0	0.88	1.9
W_PC_N0.4	9.30E+00	80.2	0.67	—
W_PC_N8	9.71E+01	41.1	1.61	2.0

Values in the table are sorted by the penetration maxima.

FIG. 3. (a) The dependence of the penetration on the MPPS for individual filters, divided into groups according to the type of filtration material. (b) Same as (a) for the dependence of the penetration on the pressure drop. The filled area is only for better readability of the plots.

FIG. 4. The dependence of the penetrations through a Zefluor 2 μm filter on face velocity. The lines only connect the measured data for better visualization of the data.

FIG. 5. The comparisons of the penetrations through various filters of the same types but of different batch numbers.

TABLE 3 Dependence of the pressure drop across the filter on the sample face velocity

Filter	Slope [kPa/cm s^−1]
W_PC_N8	44.5 ± 0.4
P_PTFE_T3	45.8 ± 0.6
P_PTFE_Z2	67.7 ± 0.4
W_Q_QM-A	122.2 ± 1.1
W_G_GF/C	182.1 ± 2.1
P_PTFE_T1	186.3 ± 1.1
M_MCE_SSWP	216.7 ± 3.9
W_PC_N0.4	823.4 ± 7.6

TABLE 4 Comparison of computed and measured maximal penetration through the Zefluor 2 μm filter

Face velocity [cm/s]		dm	EΣ	Measurement
40	dmin [nm]	161	63	25
	P [%]	86	79	4.5
17.5	dmin [nm]	193	93	40
	P [%]	81	72	1.7
8	dmin [nm]	228	128	56
	P [%]	74	65	1.2

Values in d_m column was computed using Equations (5)[5] , (6), and (7)[7] ; values in column E_Σ were computed with the whole system of Equations (S5)–(S11) given in the SI, and the measurement column holds the result of this work.