Title Page
Contents
Abstract 15
Chapter 1. Research Background 16
1. PM and public health 16
1.1. PM size distribution regarding health risks 16
1.2. PM₀.₁-induced respiratory health effects mechanism 17
2. PM₀.₁ generation for inhalation test 19
2.1. Liquid-based generation 20
2.2. Powders and bulk material dispersion 22
2.3. Gas to particle conversion generation 22
2.4. Real-time quantification and analytical techniques 24
3. PM toxicity evaluation technique 27
3.1. Inhalation exposure method 27
3.2. ALI exposure system 30
4. Conclusion 31
Reference 33
Chapter 2. Relationship between Cytotoxicity and Surface Oxidation of Artificial Black Carbon 42
1. Introduction 42
2. Materials and Methods 44
2.1. Particle Generation and Thermal Treatment 44
2.2. Physicochemical Characterization 45
2.3. Endocytosis, Cytotoxicity Assay, and Evaluation of Reactive Oxygen Species (ROS) 47
3. Results 48
3.1. Emission Characteristics of Synthesized aBC 48
3.2. Morphology 50
3.3. Chemical Surface Properties 52
3.4. In Vitro toxicity of aBC 57
4. Conclusions 61
References 63
Chapter 3. The Potential Leachate of ZnO-CB Nanoparticle from Tire Wear Particle 71
1. Introduction 71
2. Materials and Methods 73
2.1. Simulated TRWP generation and leachate experiment 73
2.2. Synthesis and Generation 74
2.3. Cell culture and exposure method 76
2.4. Biological endpoints 77
3. Results and Discussion 77
3.1. Leachate experiment 77
3.2. Chemical surface of TWP and the leaked particles 80
3.3. ZnO-CB nanoparticle synthesis 85
3.4. Generation of ZnO-CB using aerosol generator 87
3.5. Cytotoxicity results 91
4. Conclusions 93
References 94
Chapter 4. Potential Acute Toxicity by Thermal Extruder-based Nanoplastics Generation 99
1. Introduction 99
2. Materials and Methods 101
2.1. Generation design 101
2.2. Characterization 102
2.3. Effective density and exposed doses 103
2.4. Cell culture 104
2.5. Exposure method 104
2.6. Cell viability and biological endpoints 104
2.7. Statistical analysis 105
3. Results and Discussion 106
3.1. Stable generation and real-time measurement 106
3.2. Emission characterization with extruder temperature and feeding speed 108
3.3. Emission rate estimation 112
3.4. Effective density and dose estimation 115
3.5. Morphology of generated NPs 116
3.6. Detection of NPs using SERS 117
3.7. VOCs gas analysis 120
3.8. Submerged and ALI culture model. 121
4. Conclusions 126
References 127
Appendix A. α-Fe₂O₃ nanoparticles and hazardous air pollutants release during cooking using cast iron wok in a commercial Chinese restaurant 134
1. Introduction 134
2. Materials and Methods 137
3. Results and Discussion 141
3.1. Emission rate of UFPs and PM₂.₅ 141
3.2. Particle morphology and surface chemistry analyses 143
3.3. Metal and ion analyses in PM₂.₅ 146
3.4. HAPs classification 148
4. Conclusions 152
References 153
Figure 1.1. (a) PM navigate different airway with the function of aerodynamic sizes (b) PM deposition fraction in the respiratory system by... 17
Figure 1.2. (a) Mechanism of UFP induce lung diseases (b) toxicological events of UFP exposure to epithelial type I cells. 18
Figure 1.3. Collison atomizer and electrospray system for nanoparticle generation 21
Figure 1.4. Particle formation by spark discharge generator via condensation 23
Figure 1.5. Respiratory models 28
Figure 1.6. ALI exposure mechanism to aerosol VITROCELL® (Vitrocell, Germany) 30
Figure 2.1. Schematic of the experimental setup. 45
Figure 2.2. Size and time-resolved particle number concentration during heating from room temperature (RT) to 800 ℃. The red line represents the... 50
Figure 2.3. TEM image of aBC at four different temperatures which indicates no change of aBC morphology. 51
Figure 2.4. (a) SEM and (b) TEM images of aBC generated at various treatment temperatures, and (c) average particle size distribution for... 52
Figure 2.5. (a) Element and atomic concentration survey; (b) the C1s bond fraction indicates the variation in C-C, C-O, C-OH, and C=O content with... 54
Figure 2.6. OC.EC concentration at different temperatures with mass quantification to support for the increase of oxygenated content in samples... 55
Figure 2.7. (a) Raman and (b) FTIR spectra obtained for five aBC samples generated at specific treatment temperatures. 56
Figure 2.8. Deposited surface area distributions of aBC in three regions of the human respiratory tract, as predicted based on the electrical current... 58
Figure 2.9. (a) Cell viability and (b) ROS production in the naïve control (NC) and synthesized aBC-stimulated A549 cells. Data are presented as the... 59
Figure 3.1. Experimental setup 75
Figure 3.2. Morphology and SEM-EDX element mapping of TRWP collected from road simulator system. 78
Figure 3.3. SEM images of the leaked particle from simulated TWP to water 79
Figure 3.4. High resolution and TEM-EDS element mapping of the leaked particles 80
Figure 3.5. Raman mapping of 56 µm TRWP. Mapping at 2902 cm⁻¹ (blue), mapping at 1600 cm⁻¹ (red), and mapping at 520 cm⁻¹ (green). 81
Figure 3.6. XPS spectra of synthesized nanoparticles compared to leaked particle from TRWP (a) vulcanized CB and (b) CB. The suitable samples were... 82
Figure 3.7. Raman mapping of the leaked particles and comparison to the simulated TRWP and pure Carbon Black. The ZnO presence was confirmed... 83
Figure 3.8. Dynamic scattering light particle size distribution by Zeta potential and ICP, leakage quantification in (a) DI water (pH: 7), and... 85
Figure 3.9. TEM images of synthesized nanoparticle 86
Figure 3.10. TEM and FFT of synthesized particles 87
Figure 3.11. ZnO-CB aerosol generation (a) contour map of particle generation, (b) size distribution of the generated particles, and (c) TEM... 89
Figure 3.12. Visualization of generated ZnO-CB nanoparticles 90
Figure 3.13. Raman of the generated ZnO-CB nanoparticles and three deposited doses 91
Figure 3.14. TEER and Cytotoxicity of the generated particles in co-cell culture under ALI 1-hour exposure. Lactate dehydrogenase (LDH) release... 92
Figure 4.1. Experimental setup including: (1) NPs generation; (2) ALI system; and (3) NPs online measurement and sampling for offline analysis. 101
Figure 4.2. Size and time-resolved NPs number concentration when operating at different ACH using PLA filament. The ACH indicate the steady... 107
Figure 4.3. The constant particle number concentration operating at ACH of 180 h⁻¹ 108
Figure 4.4. Size and time-resolved number concentration of three types of plastic with function of nozzle temperature 110
Figure 4.5. Size and time-resolved particle number concentration with function of feeding speed 111
Figure 4.6. Total particle number concentration variation with the function of feeding rate and temperature of three filament materials 114
Figure 4.7. Effective density estimation for exposure dose quantification 115
Figure 4.8. SEM images of particles collected and primary particle size distribution and SEM-EDS elemental mapping 116
Figure 4.9. Generated NPs on conventional (a) Silicon wafer and (b) SERS substrate: Au-Pd alloy grid 117
Figure 4.10. Generated NPs collected on SERS substrate. Raman spectra of (a) virgin ABS plastic, (b) generated ABS NPs on silicon wafer, and (c) NPs... 118
Figure 4.11. Raman mapping of ABS NPs at C-H stretching (fingerprint of ABS) as the confirmation of 300-nm NPs imaging using SERS technique. 119
Figure 4.12. Gas analysis by GC-MS with the dominant distribution of styrene at 35 ppb. 121
Figure 4.13. Cytotoxicity of generated nano-plastic with submerged culture model 122
Figure 4.14. Cell morphology variation after exposure to NPs. Cell integrity loss in high concentration at figure c right after 4-h exposure. The black area... 123
Figure 4.15. Cytotoxicity of NPs after 4h exposure under ALI culture model 124