Size characterization and detection of aerosolized nanoplastics originating from evaporated thermoplastics

Figures & data

Table 1. Exemplary measurements: the table shows the settings for the set of data presented in Figure 2.

Material	Qf [L·min^−1]	T [°C]	m [g]	d1 [nm]	dmax [nm]	t [min.]
PET^p	1.6 (0.02)	200 (1)	0.025 (0.001)	2.8 (0.4)	10.0 (1.3)	30 (2)
PET	1.6 (0.02)	200 (1)	0.05 (0.001)	4.5 (0.6)	10.6 (1.4)	30 (2)
LDPE^p	1.0 (0.01)	122 (1)	0.086 (0.001)	7.7 (1)	20.5 (2.7)	56 (2)
LDPE	1.0 (0.01)	114 (1)	0.029 (0.001)	6.1 (0.8)	19.7 (2.6)	43 (2)
PP	1.6 (0.02)	125 (1)	0.038 (0.001)	11.2 (1.5)	29.3 (3.8)	56 (2)

Q_f represents the flow rate of air passing the tube furnace, T marks the set point temperature of the tube furnace, m is the amount of seed particle material on the crucible and t denotes the dwell time in the furnace. d₁ is the diameter corresponding to 1% of the maximum particle number concentration in the distribution on the lower size end. d_max is the diameter corresponding to the maximum of the distribution. The rounded brackets contain the measurement uncertainties.

Table 2. 50% cutoff diameters: The table shows the 50% cutoff diameters (d₅₀) measured for PET^p and PET using the TSI 3772 and the Airmodus A20.

Material	CPC	d50 [nm]
PET^p	TSI 3772	7.4 (1.0)
	A20	4.6 (0.6)
PET	TSI 3772	7.4 (1.0)
	A20	4.4 (0.6)

The rounded brackets contain the measurement uncertainties.

Figure 1. Schematic of the experimental setup: A tube furnace was used for particle generation. The aerosol exiting the tube furnace is brought into a stable charging state using a soft X-ray charger and fed into a DMA that is operated in analyzer-mode. The particles are detected using a Faraday Cup Electrometer and a CPC.

Figure 2. Set of particle number size distributions: The figure shows a set of representative particle number size distributions for the investigated materials. The exact settings for every distribution are presented in Table 1. Panel (a) shows the data measured with PET^p and LDPE^p. Panel (b) shows the results for PET, LDPE, and PP. The higher-purity materials are marked with “p”.

Figure 3. Stability: The figure shows the temporal evolution of the particle number size distributions for two different materials. The curves correspond to different dwell times of the materials in the tube furnace. Panel (a) corresponds to measurement using PET and a set point temperature of 180 °C. Panel (b) shows the temporal evolution of the size distribution measured with PET^p at 220 °C.

Figure 4. Effects of temperature, flow rates and amount of material: The figure shows the influence of different flow rates (panel (a), PET^p, 200 °C), amounts of material (panel (b), PET^p, 200 °C) and set point temperatures (panel (c), PET^p, 160–200 °C). Panel (d) presents the results of the direct comparison between PET^p and PET using identical settings.

Figure 5. 50% cutoff diameters: The figure presents the results of the measurements of the 50% cutoff diameter for PET^p and PET using the TSI 3772 and Airmodus A20 as particle detectors. The triangles correspond to the TSI 3772, the rings to the Airmodus A20. The black data points correspond to the results of Wlasits et al. (2020). Panel (a) shows the comparison of the 50% cutoff diameters for PET^p to the aforementioned study. Panel (b) presents the 50% cutoff diameters for both CPCs based on measurements using PET^p and PET.

Wlasits, P. J., D. Stolzenburg, C. Tauber, S. Brilke, S. H. Schmitt, P. M. Winkler, D. Wimmer. 2020. Counting on chemistry: laboratory evaluation of seed-material-dependent detection efficiencies of ultrafine condensation particle counters. Atmos. Meas. Tech. 13 (7):3787–98. doi: 10.5194/amt-13-3787-2020.

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