Aerosol Sampling: Science, Standards, Instrumentation and Applications

Preface xvii

A SCIENTIFIC FRAMEWORK FOR AEROSOL SAMPLING 1

1 Introduction 3

1.1 Aerosols 3

1.2 Particle size 4

1.3 Elementary particle size statistics 5

1.4 Aerosol measurement 8

1.5 Sampler performance characteristics 9

References 12

2 Fluid and aerosol mechanical background 13

2.1 Fluid mechanical background 13

2.2 Aerosol mechanics 22

References 33

3 Experimental methods in aerosol sampler studies 35

3.1 Introduction 35

3.2 Methodology for assessing sampler performance 35

3.3 Scaling relationships for aerosol samplers 38

3.4 Test facilities 39

3.5 Test aerosol generation 50

3.6 Reference methods 60

3.7 Assessment of collected aerosol 60

3.8 Aerosol sampler test protocols and procedures 61

References 68

4 The nature of air flow near aerosol samplers 71

4.1 Introduction 71

4.2 Line and point sink samplers 71

4.3 Thin-walled slot and tube entries 73

4.4 Thick-walled tubes 75

4.5 Simple blunt samplers facing the wind 76

4.6 Blunt samplers with orientations other than facing the wind 82

4.7 More complex sampling systems 89

4.8 Effects of freestream turbulence 90

References 90

5 Aerosol aspiration in moving air 93

5.1 Introduction 93

5.2 Thin-walled tube samplers 94

5.3 Blunt samplers 116

References 127

6 Aspiration in calm and slowly moving air 131

6.1 Introduction 131

6.2 Sampling in perfectly calm air 131

6.3 Slowly moving air 149

References 155

7 Interferences to aerosol sampling 157

7.1 Introduction 157

7.2 Interferences during aspiration 157

7.3 Interferences after aspiration 173

References 188

8 Options for aerosol particle size selection after aspiration 193

8.1 Introduction 193

8.2 Elutriation 194

8.3 Filtration by porous foam media 197

8.4 Centrifugation 201

8.5 Impaction 205

8.6 Diffusion 211

8.7 Other particle size-selective mechanisms 213

References 215

B STANDARDS FOR AEROSOLS 219

9 Framework for aerosol sampling in working, living and ambient environments 221

9.1 Introduction 221

9.2 Exposure to aerosols 222

9.3 Framework for health-related aerosol sampling 227

9.4 Non-health-related aerosol standards 233

References 235

10 Particle size-selective criteria for coarse aerosol fractions 237

10.1 Introduction 237

10.2 Experimental studies of inhalability 237

10.3 Particle size-selective criteria for the inhalable fraction 247

10.4 Overview 252

References 253

11 Particle size-selective criteria for fine aerosol fractions 255

11.1 Introduction 255

11.2 Studies of regional deposition of inhaled aerosols 255

11.3 Criteria for fine aerosol fractions 268

11.4 Overview 282

References 285

12 Health effects and Limit values 289

12.1 Introduction 289

12.2 Aerosol-related health effects 289

12.3 The processes of standards setting 292

12.4 Occupational exposure limits (OELs) 292

12.5 Ambient atmospheric aerosol limits 297

12.6 Special cases 301

References 305

C AEROSOL SAMPLING INSTRUMENTATION 309

13 Historical milestones in practical aerosol sampling 311

13.1 Introduction 311

13.2 Occupational aerosol sampling 312

13.3 Ambient atmospheric aerosol sampling 319

References 323

14 Sampling for coarse aerosols in workplaces 327

14.1 Introduction 327

14.2 Static (or area) samplers for coarse aerosol fractions 327

14.3 Personal samplers for coarse aerosol fractions 333

14.4 Analysis of performance data for inhalable aerosol samplers 352

14.5 Passive aerosol samplers 354

References 356

15 Sampling for fine aerosol fractions in workplaces 359

15.1 Introduction 359

15.2 Samplers for the respirable fraction 359

15.3 Samplers for the thoracic fraction 385

15.4 Samplers for PM2.5 391

15.5 Thoracic particle size selection for fibrous aerosols 393

15.6 Sampling for very fine aerosols 394

15.7 Simultaneous sampling for more than one aerosol fraction 395

References 398

16 Sampling in stacks and ducts 403

16.1 Introduction 403

16.2 Basic considerations 403

16.3 Stack sampling methods 404

16.4 Sampling probes for stack sampling 410

16.5 Sampling for determining particle size distribution in stacks 414

16.6 Direct-reading stack-monitoring instruments 415

References 415

17 Sampling for aerosols in the ambient atmosphere 417

17.1 Introduction 417

17.2 Sampling for coarse ‘nuisance’ aerosols 417

17.3 Sampling for ‘black smoke’ 423

17.4 Sampling for total suspended particulate in the ambient atmosphere 425

17.5 Sampling for fine aerosol fractions in the ambient atmosphere 432

17.6 Meteorological sampling 440

References 442

18 Sampling for the determination of particle size distribution 447

18.1 Introduction 447

18.2 Rationale 447

18.3 Aerosol spectrometers 448

18.4 Cascade impactors 452

18.5 Other spectrometers 465

18.6 Particle size distribution analysis by microscopy 469

References 470

19 Sampling for bioaerosols 473

19.1 Introduction 473

19.2 Standards for bioaerosols 474

19.3 Technical issues for bioaerosol sampling 474

19.4 Early bioaerosol sampling 476

19.5 Criteria for bioaerosol sampling 477

19.6 Inertial samplers 477

19.7 Centrifugal samplers 485

19.8 ‘Total’ and inhalable bioaerosol 486

19.9 Other samplers 486

References 486

20 Direct-reading aerosol sampling instruments 489

20.1 Introduction 489

20.2 Optical aerosol-measuring instruments 490

20.3 Electrical particle measurement 503

20.4 Condensation nuclei/particle counters 504

20.5 Mechanical aerosol mass measurement 505

20.6 Nuclear mass detectors 509

20.7 Surface area monitoring 510

20.8 Analytical chemical methods 511

20.9 Bioaerosol monitoring 511

References 513

D AEROSOL SAMPLE APPLICATIONS AND FIELD STUDIES 517

21 Pumps and paraphernalia 519

21.1 Introduction 519

21.2 Air moving systems 519

21.3 Flow rate 524

21.4 Collection media 526

21.5 Analysis of collected samples 533

References 535

22 Field experience with aerosol samplers in workplaces 537

22.1 Introduction 537

22.2 Personal and static (or area) sampling 538

22.3 Relationship between ‘total’ and inhalable aerosol 539

22.4 Converting particle counts to particle mass 549

22.5 Field experience with samplers for respirable aerosol 558

22.6 Classification of workplace aerosols 562

22.7 Diesel particulate matter 568

22.8 The future of workplace aerosol measurement 569

References 570

23 Field experience with aerosol samplers in the ambient atmosphere 575

23.1 Introduction 575

23.2 ‘Nuisance’ dust 576

23.3 Total suspended particulate and black smoke 577

23.4 Black smoke and particle size fractions (PM10 and PM2.5) 580

23.5 Transition to particle size-selective sampling 582

23.6 PM10 585

23.7 PM2.5 589

23.8 Personal exposures to PM10 and PM2.5 589

23.9 Classification of ambient atmospheric aerosols 593

References 596

Index 599