Real-Time Characterization of the Composition of Individual Particles Emitted From Ultrafine Particle Concentrators

Figures & data

FIG. 1 Experimental set-up used for the particle concentrator experiments. See text for details.

TABLE 1 Operating parameters for HUCAPS and its prototype

	Rochester	Boston	Chapel Hill
Inlet
Inlet flow	2000 L/min	5000 L/min	5000 L/min
Temperature	21.6°C	27.5°C	26.1°C
Relative humidity	45.8%	50.9%	65.2%
Saturation conditions
Tsaturator	—	29.5°C	27.9°C
RHsaturator	—	72.0%	75.9%
Tcondenser	—	6.7°C	5.9°C
Drying conditions
Drying flow	N/A	8 L/min	15 L/min
Tdrying	N/A	121°C	120°C
Treshaper	N/A	36.4°C	35.9°C
RHreshaper	N/A	40%	46%
Outlet conditions
Temperature	—	27.8°C	28.0°C
Relative humidity	100%	60.3%	66.6%
Total outlet flow	20 L/min	58 L/min	65 L/min
Dilution conditions
Diluting air	Particle-free	Particle-free	Particle-free
	medical grade air	ambient air	ambient air
Dilution factor	1:14	1:17	1:48

FIG. 2 Particle number distribution versus particle size for (a) HUCAPS I, (b) HUCAPS III, (c) HUCAPS II, and (d) VACES.

TABLE 2 SMPS statistics for non-concentrated (NC) and concentrated (C) particles and concentration enrichment factors

	Rochester		Boston		Chapel Hill		Tuxedo Park
	NC	C	NC	C	NC	C	NC	C
Median (nm)	18	43	40	75	79	87	83	88
Mean (nm)	26	51	69	88	96	100	100	103
Total conc. (#/cc)	22,889	129,410	4093	263,919	5711	227,350	15,662	171,400
Enrichment factor	5.6		63		40		11

FIG. 3 Size dependent concentration enrichment factor for the HUCAPS II and VACES.

FIG. 4 Single particle ATOFMS mass spectra for (a) EC, (b) ECOC, (c) OC, (d) PAH, and (e) amine type particles.

FIG. 5 Number fraction of EC, ECOC, OC, amine, and PAH particles for (a) HUCAPS I, (b) HUCAPS III, (c) HUCAPS II, and (d) VACES.

FIG. 6 Average SMPS number distribution versus particle size for non-concentrated and concentrated particles at S_R = 2.5, 2.8, and 3.0.

TABLE 3 Concentration enrichment factors and SMPS statistics for non-concentrated (NC) and concentrated (C) particles under different saturation ratio (S_R) in Boston

	SR = 2.5		SR = 2.8		SR = 3.0
	NC	C	NC	C	NC	C
Median (nm)	34	65	35	73	40	75
Mean (nm)	57	84	61	86	69	88
Total conc. (#/cc)	5254	21,860	4332	203,274	4093	263,919
Enrichment factor	4.1		47		63

FIG. 7 Number fraction of EC, ECOC, OC, amine, and PAH particles in the (a) ultrafine (50–100 nm), and (b) fine (100–300 nm) modes at S_R = 2.5, 2.8, and 3.0.

FIG. 8 Processes of particle growth and desolvation/evaporation occurring in the concentrator.

FIG. 9 Single particle mass spectra of (a) an E¹³C particle, and (b) an E¹³C-OC particle.

FIG. 10 Number concentration distribution verus particle size for particle-free room air with ¹³C-containing particles and ambient air with ¹³C-containing particles.

TABLE 4 SMPS statistics for non-concentrated (NC) and concentrated (C) particles and concentration enrichment factors for the HUCAPS ¹³C experiments

	Particle-free room air				Ambient air
	Without ^13C		With ^13C		With ^13C
	NC	C	NC	C	NC	C
Median (nm)	39.7	72.9	39.0	62.9	30.7	57.5
Mean (nm)	54.3	85.1	41.8	70.5	30.2	70.5
Total conc.	566	22906	37,588	630,314	59,837	911,139
(#/cc)
Enrichment factor	40.4		16.7		15.2

FIG. 11 Number fractions of different particle types in (a) ¹³C-containing particles, (b) Particle-free room air with ¹³C-containing particles, and (c) ambient air with ¹³C-containing particles.

FIG. 12 OC/EC ion intensity ratios as a function of size upstream and downstream of HUCAPS.

FIG. 13 ATOFMS spectra of (a) a non-concentrated OC particle, and (b) a concentrated OC particle.