Preface to the First Edition xi
Preface to the Second Edition xiii
List of Principal Symbols xv
1 Introduction 1
1.1 Definitions 3
1.2 Particle Size, Shape, and Density 8
1.3 Aerosol Concentration 10
Problems 12
References 13
2 Properties of Gases 15
2.1 Kinetic Theory of Gases 15
2.2 Molecular Velocity 18
2.3 Mean Free Path 21
2.4 Other Properties 23
2.5 Reynolds Number 27
2.6 Measurement of Velocity, Flow Rate, and Pressure 31
Problems 39
References 41
3 Uniform Particle Motion 42
3.1 Newton's Resistance Law 42
3.2 Stokes's Law 44
3.3 Settling Velocity and Mechanical Mobility 46
3.4 Slip Correction Factor 48
3.5 Nonspherical Particles 51
3.6 Aerodynamic Diameter 53
3.7 Settling at High Reynolds Numbers 55
3.8 Stirred Settling 62
3.9 Instruments That Rely on Settling Velocity 65
3.10 Appendix: Derivation of Stokes's Law 67
Problems 70
References 73
4. Particle Size Statistics 75
4.1 Properties of Size Distributions 75
4.2 Moment Averages 82
4.3 Moment Distributions 84
4.4 The Lognormal Distribution 90
4.5 Log-Probability Graphs 94
4.6 The Hatch-Choate Conversion Equations 97
4.7 Statistical Accuracy 100
4.8 Appendix 1: Distributions Applied to Particle Size 104
4.9 Appendix 2: Theoretical Basis for Aerosol Particle Size Distributions 105
4.10 Appendix 3: Derivation of the Hatch-Choate Equations 105
Problems 108
References 110
5. Straight-Line Acceleration and Curvilinear Particle Motion 111
5.1 Relaxation Time 111
5.2 Straight-Line Particle Acceleration 112
5.3 Stopping Distance 117
5.4 Curvilinear Motion and Stokes Number 119
5.5 Inertial Impaction 121
5.6 Cascade Impactors 128
5.7 Virtual Impactors 134
5.8 Time-of-Flight Instruments 136
Problems 138
References 140
6. Adhesion of Particles 141
6.1 Adhesive Forces 141
6.2 Detachment of Particles 144
6.3 Resuspension 145
6.4 Particle Bounce 146
Problems 147
References 148
7 Brownian Motion and Diffusion 150
7.1 Diffusion Coefficient 150
7.2 Particle Mean Free Path 154
7.3 Brownian Displacement 156
7.4 Deposition by Diffusion 160
7.5 Diffusion Batteries 165
Problems 168
References 169
8 Thermal and Radiometrie Forces 171
8.1 Thermophoresis 171
8.2 Thermal Precipitators 176
8.3 Radiometrie and Concentration Gradiant Forces 178
Problems 180
References 180
9 Filtration 182
9.1 Macroscopic Properties of Filters 182
9.2 Single-Fiber Efficiency 190
9.3 Deposition Mechanisms 191
9.4 Filter Efficiency 196
9.5 Pressure Drop 200
9.6 Membrane Filters 202
Problems 204
References 204
10 Sampling and Measurement of Concentration 206
10.1 Isokinetic Sampling 206
10.2 Sampling from Still Air 213
10.3 Transport Losses 216
10.4 Measurement of Mass Concentration 217
10.5 Direct-Reading Instruments 222
10.6 Measurement of Number Concentration 225
10.7 Sampling Pumps 228
Problems 230
References 231
11 Respiratory Deposition 233
11.1 The Respiratory System 233
11.2 Deposition 235
11.3 Deposition Models 242
11.4 Inhalability of Particles 245
11.5 Respirable and Other Size-Selective Sampling 249
Problems 257
References 258
12 Coagulation 260
12.1 Simple Monodisperse Coagulation 260
12.2 Polydisperse Coagulation 268
12.3 Kinematic Coagulation 272
Problems 276
References 277
13 Condensation and Evaporation 278
13.1 Definitions 278
13.2 Kelvin Effect 281
13.3 Homogeneous Nucleation 283
13.4 Growth by Condensation 285
13.5 Nucleated Condensation 288
13.6 Condensation Nuclei Counters 292
13.7 Evaporation 294
Problems 301
References 302
14 Atmospheric Aerosols 304
14.1 Natural Background Aerosol 304
14.2 Urban Aerosol 307
14.3 Global Effects 312
Problems 314
References 315
15 Electrical Properties 316
15.1 Units 316
15.2 Electric Fields 318
15.3 Electrical Mobility 320
15.4 Charging Mechanisms 323
15.5 Corona Discharge 331
15.6 Charge Limits 333
15.7 Equilibrium Charge Distribution 335
15.8 Electrostatic Precipitators 338
15.9 Electrical Measurement of Aerosols 341
Problems 346
References 347
16 Optical Properties 349
16.1 Definitions 350
16.2 Extinction 352
16.3 Scattering 358
16.4 Visibility 364
16.5 Optical Measurement of Aerosols 370
Problems 376
References 377
17 Bulk Motion of Aerosols 379
Problems 385
References 385
18 Dust Explosions 386
Problems 392
References 392
19 Bioaerosols 394
19.1 Characteristics 394
19.2 Sampling 396
Problems 400
References 400
20 Microscopic Measurement of Particle Size 402
20.1 Equivalent Sizes of Irregular Particles 402
20.2 Fractal Dimension of Particles 408
20.3 Optical Microscopy 413
20.4 Electron Microscopy 416
20.5 Asbestos Counting 422
20.6 Automatic Sizing Methods 424
Problems 425
References 426
21 Production of Test Aerosols 428
21.1 Atomization of Liquids 428
21.2 Atomization of Monodisperse Particles in Liquid Suspensions 434
21.3 Dispersion of Powders 438
21.4 Condensation Methods 443
Problems 445
References 446
Appendices 447
A1. Useful Constants and Conversions Factors 447
A2. Some Basic Physical Laws 449
A3. Relative Density of Common Aerosol Materials 451
A4. Standard Sieve Sizes 451
A5. Properties of Gases and Vapors at 293 K [20°C] and 101 kPa [1 atm] 452
A6. Viscosity and Density of Air versus Temperature 452
A7. Pressure, Temperature, Density, and Mean Free Path of Air versus Altitude 453
A8. Properties of Water Vapor 455
A9. Properties of Water 455
A10. Particle Size Range of Aerosol Properties and Measurement Instruments 456
All. Properties of Airborne Particles at Standard Conditions 458
A12. Slip Correction Factor for Standard and Nonstandard Conditions 460
A13. Properties of Selected Low-Vapor-Pressure Liquids 461
A14. Reference Values for Atmospheric Properties at Sea Level and 293 K [20°C] 462
A15. Greek Symbols Used in This Book 464
A16. SI Prefixes 464
Index 465
