Intercomparison of a portable and two stationary mobility particle sizers for nanoscale aerosol measurements

Figures & data

Table 1. Specifications of instruments used in this study.

ID	Manufacturer and Model	Studied metric	Size range [nm]	Time resolution [s]	Aerosol flow rate [L min^−^1]	Sheath flow rate [L min^−^1]	Software version	Other settings
SMPS-L	TSI SMPS, Model 3936 long	PNC^a + PSD^b	9.7–421.7 19.1–897.7	180	0.6 0.2	6 2	AIM, version 9.0.0.0	Long DMA (TSI, Model 3081) + CPC (TSI, Model 3772) ^85Kr bipolar neutralizer (74 MBq, TSI model 3077)
SMPS-N	TSI SMPS, Model 3936 nano	PNC^a + PSD^b	3.2–107.5	180	0.6	6	AIM, version 9.0.0.0	Nano DMA (TSI, Model 3085) + UWCPC (TSI, Model 3786) ^85Kr bipolar neutralizer (74 MBq, TSI model 3077)
NanoScan	TSI SMPS, Model 3910	PNC^a + PSD^b	10–420	60	0.75	–	NanoScan Manager Version 1.0.0.19	Non-radioactive unipolar diffusion charger (corona jet type)
UCPC	TSI UCPC, Model 3776	PNC^a	2.5–3000	1	1.5	–	AIM, version 9.0.0.0	–

^aPNC: PN concentration; ^bPSD: particle size distribution.

Table 2. Parameters of the fitted lognormal particle number size distributions (total number concentrations, modal diameter, and standard deviations) measured by the SMPSs (NanoScan, SMPS-L, and SMPS-N) and UCPC measuring compact and spherical particles (number 1–6 in Table S1 in the SI); all concentrations (PN_total) in [cm⁻³] and all diameters (D_mode) in [nm].

		NaCl			DEHS
Experiment		#1	#2	#3	#4	#5	#6
UCPC PN total ± σ [cm^−^3]		7.9 ± 0.3 × 10^4	1.8 ± 0.3 × 10^4	1.6 ± 0.7 × 10^5	2.1 ± 0.03 × 10^4	9.9 ± 0.2 × 10^4	4.2 ± 0.3 × 10^4
NanoScan	PN total ± σ [cm^−^3]	2.1 ± 0.1 × 10^4	1.8 ± 0.4 × 10^4	2.1 ± 0.2 × 10^5	2.3 ± 0.02 × 10^4	1.0 ± 0.1 × 10^5	5.1 ± 0.6 × 10^4
SMPS-L		^*	1.6 ± 0.3 × 10^4	1.7 ± 0.1 × 10^5	2.1 ± 0.04 × 10^4	1.0 ± 0.05 × 10^5	4.0 ± 0.3 × 10^4
SMPS-N		7.8 ± 0.5 × 10^4	1.7 ± 0.3 × 10^4	1.9 ± 0.1 × 10^5	^*	^*	^*
NanoScan	Dmode ± σ [nm]	13.2 ± 0.09	72.9 ± 2.4	68.6 ± 2.1	173.6 ± 2.5	182.2 ± 2.6	131.6 ± 1.6
SMPS-L		^*	64.3 ± 0.3	58.7 ± 0.3	231.2 ± 3.9	228.2 ± 1.4	198.8 ± 1.3
SMPS-N		10.6 ± 0.04	73.6 ± 1.3	64.3 ± 0.6	^*	^*	^*

σ : Standard deviation.

* Non-overlapping size.

Values in bold: considered internal reference value for total N concentration (UCPC) and for particle number size distributions (SMPS-N or SMPS-L).

Table 3. Parameters of the fitted lognormal particle number size distributions (total number concentrations, modal diameter, and standard deviations) measured by the SMPSs (NanoScan, SMPS-L and SMPS-N) and UCPC measuring agglomerated particles (number 7 to 12 in Table S1 in the SI); all concentrations (PN_total) in [cm⁻³] and all diameters (D_mode) in [nm]. Values in bold: considered internal reference value for total PN concentration (UCPC) and for particle number size distributions (SMPS-N or SMPS-L).

		ZnO	Spark Generated Soot				Diesel Soot
Experiment		#7	#8	#9	#10	#11	#12
UCPC PN total ± σ [cm^−^3]		1.3 ± 0.03 × 10^5	1.5 ± 0.02 × 10^4	1.0 ± 0.02 × 10^5	1.1 ± 0.02 × 10^4	7.9 ± 0.2 × 10^4	1.2 ± 0.09 × 10^5
NanoScan	PN total ± σ [cm^−^3]	1.8 ± 0.2 × 10^5	1.8 ± 0.1 × 10^4	1.4 ± 0.1 × 10^5	1.6 ± 0.02 × 10^4	1.3 ± 0.05 × 10^5	1.9 ± 0.2 × 10^5
SMPS-L		1.5 ± 0.09 × 10^5	1.6 ± 0.1 × 10^4	1.1 ± 0.04 × 10^5	1.1 ± 0.02 × 10^4	7.2 ± 0.3 × 10^4	1.2 ± 0.1 × 10^5
SMPS-N		1.5 ± 0.1 × 10^5	1.8 ± 0.2 × 10^4	1.1 ± 0.03 × 10^5	^*	^*	^*
NanoScan	Dmode ± σ [nm]	67.4 ± 0.9	49.1 ± 0.7	63.2 ± 0.9	74.6 ± 1.1	91.1 ± 1.7	95.1 ± 1.5
SMPS-L		66.2 ± 0.3	47.9 ± 0.3	66.7 ± 0.2	81.9 ± 0.2	105.4 ± 0.2	95.6 ± 0.5
SMPS-N		66.9 ± 0.3	48.6 ± 0.3	70.7 ± 0.5	^*	^*	^*

σ : Standard deviation.

* Non-overlapping size.

Figure 1. Relative difference in PN concentration between the three SMPSs and UCPC measurement. Error bars indicate the standard deviation (±σ). The dashed (red) horizontal line indicates the considered arbitrary threshold of ±20% difference between PN measured (NanoScan, SMPSs) and PN expected (UCPC).

Figure 2. Relative difference in modal diameter between NanoScan and SMPS-L measurement (gray columns) and SMPS-N (black column). Error bars indicate the standard deviation (±σ). The dashed (red) horizontal line indicates the considered arbitrary threshold of ±20% difference between PN measured (NanoScan, SMPSs) and PN expected (UCPC).

Figure 3. Measurement data and fitted particle number size distribution of generated particles measured in the exposure chamber with SMPS-N, SMPS-L and NanoScan: (a) 11 nm NaCl #1; (b) 60 nm NaCl #3 at high concentration and; (c) 199 nm DEHS #6. Error bars indicate the standard deviation. p = p-value.

Figure 4. Measurement data and fitted particle number size distribution of generated 66 nm ZnO particles (#7), measured in the exposure chamber with SMPSs and NanoScan. Error bars indicate the standard deviation. p = p-value.

Figure 5. TEM images of collected samples: (a) 67 nm spark soot at high concentration (spark generated soot #9); (b) and (c) 105 nm spark generated soot at high concentration (spark generated soot #11).

Figure 6. (Left) Measurement data and fitted particle number size distribution of generated 96 nm diesel soot particles at high concentrations, measured in the exposure chamber with SMPS-L and NanoScan. Error bars indicate the standard deviation. p = p-value. (Right) TEM image of collected diesel soot particles.

Table 4. Parameters of the fitted lognormal particle number size distributions (total number concentrations, modal diameter, and standard deviations) measured by the SMPSs (NanoScan, SMPS-L and SMPS-N) and UCPC measuring multimodal aerosols (number 13 to 15 in Table S1 in the SI); all concentrations (PN_total) in [cm⁻³] and all diameters (D_mode) in [nm].

		Multimodal aerosols
No. of experiment		Diesel soot #13	NaCl #14	NaCl/DEHS #15
UCPC PNtotal ± σ [cm^−^3]		2.3 ± 0.07 × 10^5	1.7 ± 0.04 × 10^5	2.9 ± 0.4 × 10^5
NanoScan	PN total ± σ [cm^−^3]	2.8 ± 0.1 × 10^5	1.9 ± 0.2 × 10^5	3.3 ± 0.9 × 10^5
SMPS-L		2.5 ± 0.1 × 10^5	2.5 ± 0.07 × 10^5	4.1 ± 0.7 × 10^5
SMPS-N		2.7 ± 0.2 × 10^5	2.5 ± 0.1 × 10^5	3.2 ± 0.5 × 10^5
NanoScan	D mode ± σ [nm]	30.9 ± 1.9/48.1 ± 2.2	50.9 ± 0.7	66.6 ± 1.1
SMPS-L		30.7 ± 0.1/136.4 ± 1.1	27.4 ± 0.2/61.0 ± 0.3	26.9 ± 0.5/53.8 ± 0.4/145.4 ± 2.6
SMPS-N		31.1 ± 0.1/99.4 ± 2.3	27.0 ± 0.2/59.6 ± 0.3	23.2 ± 0.4/51.9 ± 0.3/116.5 ± 5.9

σ : Standard deviation.

Values in bold: considered internal reference value for total PN concentration (UCPC) and for particle number size distributions (SMPS-N or SMPS-L).

Figure 7. (a) Measurement data and fitted particle number size distribution of generated bimodal diesel soot, measured in the exposure chamber with SMPSs and NanoScan. Error bars indicate the standard deviation. p = p-value. (b) TEM images of collected 136 nm (left) and 31 nm (right) diesel soot particles.