Sub-3 nm Particle Detection with Commercial TSI 3772 and Airmodus A20 Fine Condensation Particle Counters

Figures & data

FIG. 1. Schematic figure of the used experimental setup.

TABLE 1 Instruments compared in this study with their operation conditions

	Saturator (°C)	Condenser (°C)		Inlet flow (Lpm)	Working liquid	D50 (nm)	D10 (nm)	Test aerosol	Mean BG (#/cm3)	Settings name in text
3772	50	10		1	Butanol	3.2	1.5	Tungsten oxide	1.4	40/40
3772	46	10		1	Butanol	3.4	1.7	Tungsten oxide	0.007	36/37
3772	39	15		1	Butanol	10		Sucrose		Factory settings
A20	50	10		1	Butanol	2.7	1.4	Tungsten oxide	0.2	40/40
A20	47	10		1	Butanol	3	1.8	Tungsten oxide	0.006	36/37
A20	50	10		1.6	Butanol	2.9	1.3	Tungsten oxide	0.13	40/40
A20	47	10		1.6	Butanol	1.6	2.9	Tungsten oxide	0.003	36/37
A20	39	22		1	Butanol	7		Silver		Factory settings
3776	46	10		1.5	Butanol	1.8	1.1	Tungsten oxide	5.2	36
3776	44	10		1.5	Butanol	1.8	1.3	Tungsten oxide	0.04	34
3776	39	10		1.5	Butanol	2.3	1.9	Tungsten oxide	0	Factory settings
PSM	Varying based on calibration	Varying based on calibration		2.5	Diethylene glycol	1.4	1.1	Tungsten oxide		Factory Settings

FIG. 2. Detection efficiencies for the tuned 3772 and A20 CPCs with inlet flows of 1 Lpm, and as a comparison A11 and tuned 3776. By tuning 3772 and A20, it is possible to reach detection efficiencies comparable with the ultrafine counters.

FIG. 3. A20 detection efficiency as a function of inlet flow for 1.2-nm negative tungsten oxide particles. The detection efficiency peaks at 1.6 Lpm.

FIG. 4. Detection efficiency of A20 operated at two different inlet flows and temperature settings.

FIG. 5. Modeled supersaturation profile of A20 condenser with radius of 2.5 mm and length of 85 mm at supersaturation without homogeneous nucleation, T_condenser = 10ºC and T_saturator = 45ºC.

FIG. 6. Comparison of measured and modeled A20 detection efficiency at the brink of homogeneous nucleation.