Analytical Techniques for Atmospheric Measurement

Half Title......Page 2
Title......Page 4
Contents......Page 6
Preface......Page 13
Acknowledgements......Page 16
Contributors......Page 17
1.1.1 Our changing atmosphere......Page 20
1.1.2 The importance of atmospheric chemistry......Page 21
1.1.3 Why field measurements of atmospheric composition are important......Page 22
1.1.4 The challenges of field measurements in the atmosphere......Page 26
1.1.5 Comparison with calculations from numerical models......Page 28
1.2.1 Scope and structure of the book......Page 32
1.2.2 Previous texts describing methods for determining atmospheric composition......Page 33
1.2.3 Content of the book: Summary of individual chapters......Page 34
1.3.1 Units of concentration......Page 38
1.3.2 Selection criteria for instruments......Page 39
1.3.4 Instruments organised by analytical technique......Page 41
1.4 Instrument platforms......Page 43
1.4.1 Ground-based platforms, including vehicle-based mobile laboratories......Page 44
1.4.2 Ship-borne platforms......Page 50
1.4.3 Balloon-borne platforms......Page 51
1.4.4 Aircraft-borne platforms......Page 52
1.4.5 Commercial passenger or freight aircraft platforms......Page 53
1.4.7 Rocket platforms......Page 54
1.4.8 Satellites and other space-borne platforms......Page 55
1.5.1 LIDAR methods......Page 60
1.5.2 Matrix isolation electron spin resonance (MIESR)......Page 61
1.5.3 Solid-state and electrochemical sensors......Page 62
1.5.4 Far-infrared and microwave absorption and emission spectroscopy......Page 63
1.5.5 Measurement of fluxes of trace gases and aerosols......Page 64
1.6 Quality assurance and quality control......Page 65
1.6.1 Precision and accuracy......Page 66
1.6.2 Calibration of instruments......Page 67
1.6.3 Intercomparison of instruments......Page 69
1.7.1 Health effects and environmental policy......Page 71
1.7.2 Monitoring networks......Page 72
1.8.1 The design of field campaigns......Page 76
1.8.2 Case study of a field campaign: The 2002 NAMBLEX campaign......Page 78
1.9 Instrumented chambers for the study of simulated atmospheres......Page 81
1.10 Future directions......Page 82
Further reading......Page 86
References......Page 87
2.1 Introduction......Page 91
2.2.1 Electromagnetic radiation in the infrared......Page 92
2.2.2 Molecular interactions in the IR......Page 94
2.2.3 Vibrational bands and rotational lines in the IR......Page 96
2.2.4 Vibrational bands of atmospheric spectral features in the mid-IR......Page 100
2.2.5 Vibrational–rotational spectral line intensities......Page 103
2.3.1 IR absorption lineshapes and linewidths......Page 106
2.3.2 Beer–Lambert absorption law and absorbance......Page 113
2.4 Trace gases in the atmosphere......Page 117
2.5 Measurement approaches employing IR absorption spectroscopy......Page 118
2.5.1 In situ measurements......Page 122
2.5.2 Remote measurements......Page 153
2.6.1 Measurements of CH2O mixing ratios and model comparisons......Page 154
2.6.2 Flux measurements of CH4......Page 155
2.6.4 Isotopic ratio measurements of water in the UT/LS......Page 156
2.6.6 Future directions......Page 157
Further reading......Page 158
References......Page 159
3.1 Introduction......Page 166
3.2.1 The Beer–Lambert law......Page 167
3.2.2 Differential absorption spectroscopy......Page 168
3.2.3 Wavelength regions and differential absorption cross-sections......Page 170
3.2.4 Application to atmospheric measurements......Page 172
3.3.1 Broad-band light sources......Page 173
3.3.2 Laser sources......Page 182
3.4 DOAS using scattered sunlight......Page 187
3.4.1 Spectroscopic principles......Page 188
3.4.2 Zenith-viewing geometry: Retrieval of NO3 vertical profiles......Page 190
3.4.3 Multi-axis DOAS......Page 192
3.5 Summary and conclusions......Page 198
References......Page 199
4.1 Introduction......Page 208
4.2.1 Molecular and atomic photophysics......Page 209
4.2.2 The fluorescence signal......Page 210
4.2.3 The background......Page 212
4.2.4 The signal-to-noise ratio and detection limit......Page 213
4.2.5 General design of fluorescence instruments......Page 214
4.3 The hydroxyl radical......Page 217
4.3.1 Instruments for stratospheric and upper tropospheric OH measurements......Page 218
4.3.2 Instruments for lower tropospheric OH measurements......Page 222
4.3.4 Naphthalene......Page 225
4.3.5 Measurement of the OH lifetime......Page 226
4.4 The nitrogen oxides......Page 227
4.4.1 Photophysics of NO2......Page 228
4.4.2 Single-photon NO2 instrument design......Page 229
4.4.3 Supersonic expansions......Page 231
4.4.4 Calibration of LIF NO2 instruments......Page 232
4.4.5 Intercomparisons......Page 233
4.4.6 Thermal dissociation: LIF......Page 234
4.4.7 Two-photon LIF detection of NO......Page 236
4.4.8 Single-photon LIF detection of NO......Page 237
4.4.10 NO3 and N2O5......Page 238
4.5 Detection of halogen compounds......Page 239
4.5.1 Spectroscopy and calibration......Page 240
4.5.4 ClONO2 and ClOOCl......Page 241
Further reading......Page 242
References......Page 243
5.1.1 Generating a mass spectrum......Page 248
5.1.2 Historical development of the mass spectrometer for air measurements......Page 249
5.2.2 The atomic mass scale......Page 253
5.2.3 Resolving power and resolution......Page 255
5.3.1 Ionisation......Page 256
5.3.2 Mass filters......Page 258
5.3.3 Detectors......Page 263
5.4.1 Atmospheric pressure ionisation-chemical ionisation mass spectrometer (API-CIMS)......Page 265
5.4.2 The proton transfer reaction mass spectrometer......Page 268
5.4.3 The use of CIMS for radical measurement (OH)......Page 272
5.4.4 Coupled GC-MS capabilities......Page 275
5.4.5 The isotope ratio mass spectrometer......Page 277
5.5 Future developments......Page 279
References......Page 280
6.1 Introduction to atmospheric aerosols......Page 284
6.2 Physical aerosol measurements and sizing definitions......Page 285
6.3.1 Offline methods......Page 288
6.3.2 Online bulk sampling and analysis methods......Page 294
6.4 Online aerosol mass spectrometry......Page 295
6.4.1 Mass spectrometer types......Page 296
6.4.2 Inlet technologies......Page 299
6.4.3 Particle sizing methods......Page 301
6.4.4 Ablation and ionisation techniques......Page 304
6.5 Analysis of ambient data......Page 314
6.6 Applications of aerosol mass spectrometric techniques to atmospheric aerosol sampling......Page 316
6.7 Summary......Page 323
Further reading......Page 324
References......Page 325
7.1.1 Scope......Page 334
7.2 O3 via heterogeneous chemiluminescence......Page 335
7.2.1 Early years (luminol and rhodamine-B)......Page 336
7.2.2 Since mid-1980s (eosin Y, coumarin-47, chromotropic acid)......Page 339
7.3 O3 via electrochemistry......Page 340
7.4.1 The NO+O3 reaction......Page 342
7.4.2 The measurement of nitric oxide (NO)......Page 343
7.4.3 The measurement of nitrogen dioxide (NO2)......Page 346
7.4.4 The measurement of total reactive nitrogen (NOy )......Page 351
7.4.5 Routine NOx monitoring......Page 354
7.5.2 O3 + NO......Page 357
7.6 NO2 via luminol......Page 359
7.7.1 H2O2 via dissolution and chemiluminescence......Page 360
7.7.2 Peroxides via dissolution, derivatization, and fluorimetry......Page 361
7.7.4 HCHO via dissolution, derivatization, and HPLC......Page 363
7.7.5 HONO via liquid techniques......Page 364
7.8 Isoprene via O3 chemiluminescence......Page 365
7.9.1 Using reagent NO and CO, followed by detection of NO2......Page 367
7.9.2 Using reagent NO and SO2, followed by CIMS detection of H2SO4......Page 372
7.10 Summary and future directions......Page 376
References......Page 377
8.1 Introduction......Page 384
8.2 Gas chromatography......Page 386
8.2.1 Sample acquisition......Page 389
8.2.2 Sample preparation and injection......Page 391
8.2.3 Separation of atmospheric samples......Page 394
8.2.4 Detection......Page 397
8.2.5 Calibration and quality control......Page 400
8.2.6 Instrument deployment in the field......Page 401
8.2.7 Examples of applications of chromatography in atmospheric analysis......Page 403
8.3 Liquid chromatography......Page 414
8.3.2 Separation......Page 417
8.3.3 Detection......Page 418
8.3.4 Examples of the application of liquid chromatography in air analysis......Page 419
8.4 Future work......Page 420
References......Page 425
9.1.1 Photolysis reactions in atmospheric chemistry......Page 429
9.1.2 Photolysis frequencies: Kinetic definition......Page 431
9.1.3 Photolysis frequencies: Physical model......Page 432
9.1.5 Irradiance......Page 434
9.1.6 Actinic flux in the atmosphere......Page 435
9.2.1 Measurement requirements......Page 439
9.2.2 General measurement methods......Page 440
9.2.3 Actinic-flux sensing techniques......Page 441
9.2.4 Radiative transfer models......Page 442
9.3 Chemical actinometry......Page 443
9.3.2 Chemical kinetics considerations......Page 444
9.3.3 Optical and photochemical considerations......Page 449
9.3.4 Ozone chemical actinometers......Page 450
9.3.5 Nitrogen-dioxide chemical actinometers......Page 455
9.4.1 Principle of actinic-flux spectroradiometry......Page 460
9.4.2 Spectroradiometers for actinic-flux measurements......Page 462
9.4.3 Actinic-flux receiver optics......Page 465
9.4.4 Determination of spectral actinic fluxes......Page 467
9.4.5 Spectroradiometer calibration......Page 468
9.4.6 Determination of photolysis frequencies......Page 471
9.5.1 Filter radiometer set-up......Page 476
9.5.2 Determination of photolysis frequencies......Page 478
9.5.3 Filter radiometer calibration......Page 481
9.5.4 j(O1D) filter radiometers......Page 483
9.5.5 j(NO2) filter radiometers......Page 487
9.6 Irradiance radiometry......Page 489
9.6.1 Principle of irradiance radiometry......Page 490
9.6.2 Physical model–based methods......Page 491
9.6.3 Empirical methods......Page 494
9.7 Modelling of photolysis frequencies......Page 497
9.8.1 Photochemistry field experiments......Page 498
9.8.2 Temporal and spatial distributions......Page 499
9.8.3 Instrumental intercomparisons......Page 501
9.8.4 Molecular data assessments......Page 503
Acknowledgements......Page 505
A.1 Radiation quantities and their relationships......Page 506
A.2 Effective transmission of solar radiation into a chemical actinometer......Page 508
A.3 Spectral spectrometer bandwidth......Page 511
A.4 Correction of the angular response of an actinic-flux receiver (2πsr)......Page 512
A.5 Equivalent plane-receiver concept......Page 513
References......Page 516
Index......Page 524
Colour Plates......Page 290