Aerosol Technology: Properties, Behavior, and Measurement of Airborne Particles, Third Edition

AEROSOL TECHNOLOGY An in-depth and accessible treatment of aerosol theory and its applications The Third Edition of Aerosol Technology: Properties, Behavior, and Measurement of Airborne Particles delivers a thorough and authoritative exploration of modern aerosol theory and its applications. The book offers readers a working knowledge of the topic that reflects the numerous advances that have been made across a broad spectrum of aerosol-related application areas. New updates to the popular text include treatments of nanoparticles, the health effects of atmospheric aerosols, remote sensing, bioaerosols, and low-cost sensors. Additionally, readers will benefit from insightful new discussions of modern instruments. The authors maintain a strong focus on the fundamentals of the discipline, while providing a robust overview of real-world applications of aerosol theory. New exercise problems and examples populate the book, which also includes: * Thorough introductions to aerosol technology, key definitions, particle size, shape, density, and concentration, as well as the properties of gases * Comprehensive explorations of uniform particle motion, particle size statistics, and straight-line acceleration and curvilinear particle motion * Practical discussions of particle adhesion, Brownian motion and diffusion, thermal and radiometric forces, and filtration * In-depth examinations of sampling and measurement of concentration, respiratory deposition, coagulation, condensation, evaporation, and atmospheric aerosols Perfect for senior undergraduate and junior graduate students of science and technology, Aerosol Technology: Properties, Behavior, and Measurement of Airborne Particles will also earn a place in the libraries of professionals working in industrial hygiene, air pollution control, climate science, radiation protection, and environmental science. William C. Hinds, ScD, is an emeritus Professor in the Department of Environmental Health Science at the UCLA Fielding School of Public Health. His primary research is fundamental and applied research related to aerosols and industrial control of airborne contaminants. He is a diplomate of the American Board of Industrial Hygiene and a fellow of the American Industrial Hygiene Association, the American Association for Aerosol Research, and the International Aerosol Research Assembly. Yifang Zhu, PhD, is a Professor in the Department of Environmental Health Science at the UCLA Fielding School of Public Health. Her research is primarily in the field of air pollution, environmental exposure assessment, and aerosol science and technology. She was appointed to the California Air Resource Board (CARB)’s Research Screening Committee in January 2014. She has published more than 80 peer-reviewed journal articles on aerosols. Preface to the First Edition xi Preface to the Second Edition xiii Preface to the Third Edition xv List of Principal Symbols xvii 1 Introduction 1 1.1 Definitions 2 1.2 Particle Size, Shape, and Density 5 1.3 Aerosol Concentration 8 Problems 11 References 12 2 Properties of Gases 15 2.1 Kinetic Theory of Gases 15 2.2 Molecular Velocity 18 2.3 Mean Free Path 20 2.4 Other Properties 21 2.5 Reynolds Number 24 2.6 Measurement of Velocity, Flow Rate, and Pressure 27 Problems 35 References 36 3 Uniform Particle Motion 37 3.1 Newton’s Resistance Law 37 3.2 Stokes’s Law 39 3.3 Settling Velocity and Mechanical Mobility 40 3.4 Slip Correction Factor 42 3.5 Nonspherical Particles 44 3.6 Aerodynamic Diameter 46 3.7 Settling at High Reynolds Numbers 47 3.8 Stirred Settling 54 3.9 Instruments that Rely on Settling Velocity 56 3.10 Appendix: Derivation of Stokes’s Law 58 Problems 60 References 63 4 Particle Size Statistics 65 4.1 Properties of Size Distributions 65 4.2 Moment Averages 71 4.3 Moment Distributions 72 4.4 The Lognormal Distribution 77 4.5 Log-Probability Graphs 80 4.6 The Hatch-Choate Conversion Equations 84 4.7 Statistical Accuracy 88 4.8 Appendix 1: Distributions Applied to Particle Size 89 4.9 Appendix 2: Theoretical Basis for Aerosol Particle Size Distributions 90 4.10 Appendix 3: Derivation of the Hatch-Choate Equations 90 Problems 92 References 94 5 Straight-Line Acceleration and Curvilinear Particle Motion 97 5.1 Relaxation Time 97 5.2 Straight-Line Particle Acceleration 98 5.3 Stopping Distance 101 5.4 Curvilinear Motion and Stokes Number 104 5.5 Inertial Impaction 105 5.6 Cascade Impactors 110 5.7 Virtual Impactors 115 5.8 Time-of-Flight Instruments 117 Problems 119 References 120 6 Adhesion of Particles 121 6.1 Adhesive Forces 121 6.2 Detachment of Particles 123 6.3 Resuspension 124 6.4 Particle Bounce 126 Problems 127 References 127 7 Brownian Motion and Diffusion 129 7.1 Diffusion Coefficient 129 7.2 Particle Mean Free Path 132 7.3 Brownian Displacement 134 7.4 Deposition by Diffusion 137 7.5 Diffusion Batteries 141 Problems 144 References 145 8 Thermal and Radiometric Forces 147 8.1 Thermophoresis 147 8.2 Thermal Precipitators 151 8.3 Radiometric and Concentration Gradient Forces 153 Problems 155 References 155 9 Filtration 157 9.1 Macroscopic Properties of Filters 157 9.2 Single-Fiber Efficiency 163 9.3 Deposition Mechanisms 165 9.4 Filter Efficiency 169 9.5 Pressure Drop 174 9.6 Membrane Filters 174 Problems 176 References 176 10 Sampling and Measurement of Concentration 179 10.1 Isokinetic Sampling 179 10.2 Sampling from Still Air 185 10.3 Transport Losses 188 10.4 Measurement of Mass Concentration 189 10.5 Direct-Reading Instruments 192 10.6 Measurement of Number Concentration 195 10.7 Sampling Pumps 197 Problems 199 References 200 11 Respiratory Deposition 203 11.1 The Respiratory System 203 11.2 Deposition 206 11.3 Deposition Models 210 11.4 Inhalability of Particles 213 11.5 Respirable and Other Size-Selective Sampling 215 Problems 223 References 224 12 Coagulation 227 12.1 Simple Monodisperse Coagulation 227 12.2 Polydisperse Coagulation 233 12.3 Kinematic Coagulation 238 Problems 240 References 241 13 Condensation and Evaporation 243 13.1 Definitions 243 13.2 Kelvin Effect 246 13.3 Homogeneous Nucleation 247 13.4 Growth by Condensation 248 13.5 Nucleated Condensation 251 13.6 Condensation Particle Counters 255 13.7 Evaporation 257 Problems 261 References 263 14 Atmospheric Aerosols 265 14.1 Natural Background Aerosol 265 14.2 Urban Aerosol 269 14.3 Global Effects 274 Problems 275 References 275 15 Electrical Properties 277 15.1 Units 277 15.2 Electric Fields 278 15.3 Electrical Mobility 280 15.4 Charging Mechanisms 283 15.5 Corona Discharge 289 15.6 Charge Limits 291 15.7 Equilibrium Charge Distribution 292 15.8 Electrostatic Precipitators 294 15.9 Electrical Measurement of Aerosols 297 Problems 301 References 302 16 Optical Properties 305 16.1 Definitions 306 16.2 Extinction 307 16.3 Scattering 313 16.4 Visibility 317 16.5 Optical Measurement of Aerosols 322 Problems 329 References 330 17 Bulk Motion of Aerosols 333 Problems 338 References 338 18 Dust Explosions 339 Problems 344 References 344 19 Bioaerosols 345 19.1 Characteristics 345 19.2 Sampling 347 Problems 350 References 351 20 Microscopic Measurement of Particle Size 353 20.1 Equivalent Sizes of Irregular Particles 353 20.2 Fractal Dimension of Particles 358 20.3 Optical Microscopy 362 20.4 Electron Microscopy 365 20.5 Asbestos Counting 369 20.6 Automatic Sizing Methods 371 Problems 371 References 372 21 Production of Test Aerosols 375 21.1 Atomization of Liquids 375 21.2 Atomization of Monodisperse Particles in Liquid Suspensions 380 21.3 Dispersion of Powders 382 21.4 Condensation Methods 387 Problems 388 References 389 Appendices 391 Appendix A1. Useful Constants and Conversion Factors 391 Appendix A2. Some Basic Physical Laws 393 Appendix A3. Relative Density of Common Aerosol Materials (Multiply Values by 1000 for Density in kg/m 3 and by 1.0 for Density in g/cm 3) 394 Appendix A4. Standard Sieve Sizes 394 Appendix A5. Properties of Gases and Vapors at 293 K [20 o C] and 101 kPa [1 atm] 395 Appendix A6. Viscosity and Density of Air versus Temperature 395 Appendix A7. Pressure (a), Temperature (b), Density (c), and Mean Free Path (d) of air versus altitude 396 Appendix A8. Properties of Water Vapor 397 Appendix A9. Properties of Water 398 Appendix A10. Particle Size Range of Aerosol Properties and Measurement Instruments: (a) Application Range for Aerosol Size Measuring Instruments and (b) Size Range of Aerosol Properties (See Also Fig. 1.6) 398 Appendix A11. (a) Properties of Airborne Particles at Standard Conditions (SI Units) 400 Appendix A12. Slip Correction Factor for Standard and Nonstandard Conditions: (a) Slip Correction Factor Minus One versus Particle Diameter and Standard Conditions; (b) Slip Correction Factor versus Particle Diameter Times Pressure (per atm) for Temperatures from 233 to 893K [-40 to 600 o C] 402 Appendix A13. Properties of Selected Low-Vapor-Pressure Liquids 403 Appendix A14. Reference Values for Atmospheric Properties at Sea Level and 293.15 Ki20 o C] 404 Appendix A15. Greek Symbols Used in This Book 405 Appendix A16. SI Prefixes 405 References 405 Index 407