Indoor Aerosol Dynamics [Kõva köide]

Preface xiii

List of Abbreviations xvii

Nomenclature xxi

1 Aerosol Fundamentals 1

1.1 Introduction 1

1.2 Definitions of Aerosols 1

1.3 Sources of Aerosols 1

1.3.1 Natural Aerosol Sources 2

1.3.2 Anthropogenic Aerosol Sources 2

1.3.3 Secondary Aerosols 3

1.4 Physical Properties of Aerosol Particles 4

1.4.1 Particle Size 4

1.4.2 Particle Density 5

1.4.3 Particle Shape 6

1.4.4 Particle Surface Area 7

1.4.5 Particle Concentration 8

1.4.6 Electrical Properties of Aerosol Particles 9

1.5 Chemical Properties 10

1.6 Bioaerosol 10

1.6.1 Definition 11

1.6.2 Sources of Bioaerosols 12

1.7 Size Distribution of Aerosol Particles 12

1.7.1 Overview of Particle Sizes 12

1.7.2 Particle Size Distribution Functions 13

1.7.2.1 Normal Distribution 13

1.7.2.2 Lognormal Distribution 14

1.8 Summary 16

Problems 17

References 17

2 Particle Motion Basics 21

2.1 Introduction 21

2.2 Newtons Resistance Law 21

2.3 Stokess Law 23

2.4 Settling Velocity 25

2.5 Particle Mobility 25

2.6 Slip Correction Factor 26

2.7 Nonspherical Shape Correction 30

2.8 Aerodynamic Diameter 31

2.9 Correction to Stokess Law near BoundaryWalls 32

2.10 Summary 34

2.11 Problems 35

Appendix: Derivation of Stokess Law 36

References 39

3 Straight-Line Acceleration and Curvilinear Particle Motion 41

3.1 Introduction 41

3.2 Relaxation Time 41

3.3 Straight-Line Particle Acceleration 43

3.4 Stopping Distance 46

3.5 Curvilinear Motion 48

3.6 Stokes Number 49

3.7 Inertial Impaction 50

3.8 Summary 55

Problems 56

References 57

4 Adhesion and Detachment of Particles 59

4.1 Introduction 59

4.2 Adhesive Forces 59

4.2.1 van derWaals Force 59

4.2.2 Electrostatic Force 61

4.2.3 Surface Tension Force 61

4.2.4 Overall Adhesive Forces and Some Comparisons 62

4.3 Detachment of Particles 64

4.3.1 Methods for Measurement of Particle Detachment 64

4.3.1.1 Centrifugal Separation 64

4.3.1.2 Air Blowing for Particle Separation 64

4.3.1.3 Atomic Force Microscopy Separation 66

4.3.1.4 Vibration Separation 67

4.3.2 Comparison of Forces Acting on Particles 68

4.4 Particle Resuspension 69

4.4.1 Major Factors Affecting Particle Resuspension 69

4.4.1.1 Aerodynamic Action 70

4.4.1.2 Mechanical Disturbances 71

4.4.1.3 Electrostatic Action 73

4.4.1.4 Surface Properties 73

4.4.1.5 Particle Properties 73

4.4.2 Resuspension in Boundary Layers 73

4.4.3 Particle Resuspension Rates 74

4.5 Particle Bounce 76

4.6 Summary 77

Problems 78

References 79

5 Brownian Motion and Diffusion and Thermophoresis 81

5.1 Introduction 81

5.2 Diffusion Coefficient 81

5.3 Particle Mean Thermal Velocity 85

5.4 Particle Mean Free Path 86

5.5 Brownian Displacement 87

5.6 Diffusion Deposition 89

5.7 Thermophoresis 92

5.8 Summary 96

Problems 96

References 97

6 Sampling and Measurement of Particle Concentrations 99

6.1 Introduction 99

6.2 Particle Sampling 99

6.2.1 Isokinetic Sampling 100

6.2.2 Anisokinetic Sampling 102

6.2.2.1 Misalignment Sampling 102

6.2.2.2 Superisokinetic Sampling 104

6.2.2.3 Subisokinetic Sampling 105

6.3 Sampling from Still Air 106

6.4 Particle Transport Losses 108

6.4.1 Diffusion Deposition Loss 109

6.4.2 Inertial Deposition Loss 110

6.4.3 Electrostatic and Thermophoretic Deposition Loss 111

6.5 Off-Line Measurement of Particles 111

6.5.1 Filter Sampling 112

6.5.2 Inertial Classifier 113

6.6 Real-Time Measurement of Particles 115

6.6.1 Semi-Continuous Mass Measurement 115

6.6.2 Optical Measurement 116

6.6.2.1 Optical Particle Counter 116

6.6.2.2 Condensation Particle Counter 118

6.6.2.3 Fluorescence-based Bioaerosol Detection 118

6.7 Summary 120

Problems 121

References 122

7 Indoor Aerosol Sources 125

7.1 Introduction 125

7.2 Aerosol Sources in Households 125

7.2.1 Cooking Oil Fumes 125

7.2.1.1 Chemical Compounds in COFs 126

7.2.1.2 Emission Dynamics of COFs 126

7.2.2 Particle Emission from Heat Sources 128

7.2.2.1 Cooking Heat Sources 128

7.2.2.2 Building Heat Sources 130

7.2.3 Combustible and Electronic Cigarettes 130

7.2.4 Incense Stick and Candle Burning 132

7.2.5 Ironing 133

7.2.6 Secondary Organic Aerosols (SOAs) 133

7.2.6.1 Formation of SOAs 133

7.2.6.2 Spraying of Household Cleaning Products or Liquid Air Fresheners
134

7.2.6.3 Personal Care Products 136

7.3 Aerosol Sources in Offices 137

7.3.1 Printers 137

7.3.2 Photocopiers 138

7.3.3 Computers 140

7.4 Aerosol Sources in Lavatories 140

7.4.1 Aerosol Emission from Toilet Flushing 141

7.4.1.1 Surveyed Bioaerosol Emission after Flushing of a Toilet 141

7.4.1.2 Flushing a Sitting Toilet 143

7.4.2 Aerosol Emission from Urinal Flushing 144

7.4.3 Aerosol Emission from Handwashing 146

7.4.4 Aerosol Emission during Hand Drying under a Jet Dryer 147

7.4.5 Aerosol Emission from Showering 150

7.5 Intrusion of Outdoor Particles 151

7.5.1 Intrusion of General Outdoor Particles 151

7.5.1.1 Mechanical Ventilation Pathway 151

7.5.1.2 Natural Ventilation Pathway 152

7.5.1.3 Penetration Through Building Cracks 153

7.5.1.4 Indoor-Outdoor Particle Concentration (I/O ratio) 154

7.5.2 Intrusion of Pollens and Molds 157

7.5.2.1 Intrusion of Pollens 157

7.5.2.2 Intrusion of Molds 158

7.6 Summary 162

7.6.1 In Households 163

7.6.2 In Offices 163

7.6.3 In Lavatories 163

7.6.4 Intrusion of Outdoor Aerosols 164

Problems 165

References 166

8 Indoor Aerosol Transport Modeling 179

8.1 Introduction 179

8.2 Multizone Model 179

8.2.1 Basic Principles 179

8.2.2 Demonstration of Multizone Modeling of Airflow and Transport of a
Tracer Gas inside a House 182

8.2.3 Demonstration of Multizone Modeling of Particle Transport and CO2
Concentration in a Test Room 184

8.3 CFD Modeling of Air Motion 187

8.3.1 Governing Equations of RANS Modeling 187

8.3.2 Numerical Solution to the RANS Model 188

8.3.3 Demonstration of CFD Modeling of Airflow, Heat Transfer, and Transport
of a Tracer Gas in Indoor Environments 192

8.4 Eulerian-Based Particle Modeling 198

8.4.1 Basic Principles 198

8.4.2 Demonstration of Eulerian-Based Particle Modeling in a Ventilated
Enclosure 199

8.5 Lagrangian-Based Particle Modeling 202

8.5.1 Basic Principles 202

8.5.2 Demonstration of Lagrangian-Based Particle Modeling in a Ventilated
Enclosure 204

8.6 Multiphase Particle Modeling 207

8.6.1 Basic Principles 207

8.6.1.1 Multiphase Flow Modeling 207

8.6.1.2 Coupled EulerLagrange Modeling 208

8.6.1.3 Heat and Mass Transfer Modeling 210

8.6.2 Demonstration of Modeling of Cough Droplets in Space 212

8.6.3 Demonstration of Modeling of Liquid Aerosol Generation and Transport
during the Flushing of a Squat Toilet 214

8.7 Summary 219

Problems 220

References 222

9 Indoor Aerosol Exposure and Health Effects 225

9.1 Introduction 225

9.2 Mechanisms of Respiratory Exposure 225

9.3 Mechanisms of Toxicity of Aerosol Components 229

9.4 Health Effects of Nonbiological Aerosol Exposure 231

9.4.1 Birth Outcomes 232

9.4.2 Mortality 232

9.4.3 Atopic Allergy and Asthma 232

9.4.4 Cancer 233

9.4.5 Cardiovascular Problems 233

9.5 Health Effects of Noninfectious Bioaerosol Exposure 234

9.5.1 Asthma 234

9.5.2 Rhinitis 235

9.5.3 Chronic Airflow Obstruction 235

9.5.4 Hypersensitivity Pneumonitis 235

9.5.5 Chronic Bronchitis 235

9.5.6 Pulmonary Hemorrhage 236

9.5.7 Organic Dust Toxic Syndrome (ODTS) 236

9.5.8 Cancer 236

9.5.9 Building-related Illnesses and Symptoms 236

9.6 Summary 237

Problems 237

References 238

10 Indoor Pathogenic Aerosols and Transmission of Infection 241

10.1 Introduction 241

10.2 Shedding of Pathogenic Aerosols 241

10.2.1 Brief Introduction 241

10.2.2 Shedding of Liquid Aerosols by Breathing 242

10.2.3 Shedding of Liquid Aerosols by Talking 244

10.2.4 Shedding of Liquid Aerosols by Coughing and Sneezing 245

10.3 Transmission of Pathogenic Aerosols 247

10.3.1 Brief Introduction 247

10.3.2 Droplet Transmission 248

10.3.3 Airborne Transmission 250

10.3.4 Contact Transmission 252

10.4 Infectious Dose and Infection Risk 253

10.4.1 Brief Introduction 253

10.4.2 Minimum Dose for Infection 253

10.4.3 WellsRiley Model 254

10.4.4 Demonstration of theWellsRiley Model in a Classroom 256

10.4.5 DoseResponse Model 260

10.4.6 Demonstration of the DoseResponse Model in an Aircraft Cabin 262

10.5 Summary 265

Problems 265

References 266

11 Particle Filtration and Indoor Air Cleaning 271

11.1 Introduction 271

11.2 Fiber Filters 271

11.2.1 Filtration Mechanisms 271

11.2.1.1 Interception 271

11.2.1.2 Inertial Impaction 273

11.2.1.3 Diffusion 274

11.2.1.4 Gravitational Settling 275

11.2.1.5 Electrostatic Attraction 276

11.2.2 Performance Evaluation of Fiber Filters 276

11.2.2.1 Face Velocity and Filtration Velocity 276

11.2.2.2 Efficiency and Penetration Ratio 277

11.2.2.3 Pressure Drop 279

11.2.2.4 Quality Factor 280

11.2.2.5 Dust-holding Capacity 280

11.3 Electrostatic Precipitator 281

11.3.1 Basic Principles of ESPs 281

11.3.2 Evaluation of ESP Performance 283

11.3.2.1 Electric Field 283

11.3.2.2 Particle Migration Velocity 283

11.3.2.3 Particle Collection Efficiency 284

11.4 Operation of Air Cleaners 284

11.4.1 PM Exposure Limits 284

11.4.2 Air Cleaner Operation 286

11.4.2.1 Clean Air Delivery Rate (CADR) 286

11.4.2.2 Operation of Air Cleaners and Replacement of Air Filters 287

11.5 Summary 287

References 289

12 Inactivation of Indoor Microbial Aerosols 291

12.1 Introduction 291

12.2 Chemical Disinfectants 291

12.2.1 Alcohol-Based Disinfectants 292

12.2.2 Quaternary Ammonium Compounds 292

12.2.3 Chlorine Compounds 293

12.2.4 Hydrogen Peroxide 294

12.3 Ultraviolet Germicidal Irradiation (UVGI) 294

12.3.1 Mechanism of UVC Inactivation of Microbes 295

12.3.2 UVC Light Sources 295

12.3.2.1 Mercury-Vapor Lamps 296

12.3.2.2 Light-Emitting Diodes (LEDs) 296

12.3.2.3 Excimer Lamps 297

12.3.3 Parameters Affecting UVC Inactivation Performance 297

12.3.3.1 Microbial Species 297

12.3.3.2 Environmental Conditions 297

12.3.3.3 Medium of Microbial Attachment 297

12.3.4 Environmental and Health Safety Issues 298

12.4 Plasma Treatment 299

12.4.1 Mechanisms of Plasma Treatment 299

12.4.1.1 Etching Effect on the Cell 300

12.4.1.2 Cell Membrane Perforation and Electrostatic Disruption 300

12.4.1.3 Oxidation of Intracellular Macromolecules 301

12.4.2 Effectiveness of Plasma Treatment 301

12.5 Other Disinfection Technologies 303

12.5.1 Ozone Oxidation 303

12.5.2 Photocatalytic Oxidation (PCO) 304

12.6 Summary 305

Problems 305

References 306

Appendices 311

Index 319

TENGFEI (TIM) ZHANG is a Professor at Dalian University of Technology and Adjunct Professor at Tianjin University. He holds degrees from Purdue University, Tsinghua University, and Southeast University. As a recognized expert in his field, he has received numerous awards and serves as an editor of the journal of Building and Environment. Dr. Zhang has led major national and international research projects and chaired the Healthy Buildings 2023 Asia-Pacific Conference.

FEI LIU is an Assistant Professor at Qingdao University of Technology. He received his PhD from Tianjin University and conducted visiting research at KTH. His research interests cover building ventilation and indoor air quality. Dr. Liu has published multiple papers in high-impact journals. He is a member of the International Society of Energy and Built Environment (ISEBE).