IAN COLBECK, University of Essex, UK MIHALIS LAZARIDIS, Technical University of Crete, Greece

• List of Contributors xiiiPreface xv1. Introduction 1Mihalis Lazaridis and Ian Colbeck1.1 Introduction 11.2 Size and Shape 51.3 Size Distribution 61.4 Chemical Composition 101.5 Measurements and Sampling 11References 122. Aerosol Dynamics 15Mihalis Lazaridis and Yannis Drossinos2.1 Introduction 152.2 General Dynamic Equation 172.2.1 Discrete Particle Size Distribution 182.2.2 Continuous Particle Size Distribution 192.3 Nucleation: New Particle Formation 192.3.1 Classical Nucleation Theory 202.3.2 Multicomponent Nucleation 222.3.3 Heterogeneous Nucleation 232.3.4 Atmospheric Nucleation 242.4 Growth by Condensation 262.5 Coagulation and Agglomeration 272.5.1 Brownian Coagulation 282.5.2 Agglomeration 282.6 Deposition Mechanisms 322.6.1 Stokes Law 322.6.2 Gravitational Settling 322.6.3 Deposition by Diffusion 342.6.4 Deposition by Impaction 342.6.5 Phoretic Effects 342.6.6 Atmospheric Aerosol Deposition 352.6.7 Deposition in the Human Respiratory Tract 362.7 Resuspension 382.7.1 Monolayer Resuspension 382.7.2 Multilayer Resuspension 39References 413. Recommendations for Aerosol Sampling 45Alfred Wiedensohler, Wolfram Birmili, Jean-Philippe Putaud, and John Ogren3.1 Introduction 453.2 Guidelines for Standardized Aerosol Sampling 463.2.1 General Recommendations 463.2.2 Standardization of Aerosol Inlets 473.2.3 Humidity Control 493.3 Concrete Sampling Configurations 533.3.1 General Aspects of Particle Motion 533.3.2 Laminar Flow Sampling Configuration 543.3.3 Turbulent Flow Sampling Configuration 553.4 Artifact-Free Sampling for Organic Carbon Analysis 57Acknowledgements 59References 594. Aerosol Instrumentation 61Da-Ren Chen and David Y. H. Pui4.1 Introduction 614.2 General Strategy 624.3 Aerosol Sampling Inlets and Transport 634.4 Integral Moment Measurement 644.4.1 Total Number Concentration Measurement: Condensation Particle Counter (CPC) 654.4.2 Total Mass Concentration Measurement: Quartz-Crystal Microbalance (QCM) and Tapered-Element Oscillating Microbalance (TEOM) 664.4.3 Light-Scattering Photometers and Nephelometers 674.5 Particle Surface Area Measurement 684.6 Size-Distribution Measurement 704.6.1 Techniques based on Particle–Light Interaction 704.6.2 Techniques based on Particle Inertia 714.6.3 Techniques based on Particle Electrical Mobility 744.6.4 Techniques based on Particle Diffusion 774.7 Chemical Composition Measurement 784.8 Conclusion 80References 825. Filtration Mechanisms 89Sarah Dunnett5.1 Introduction 895.2 Deposition Mechanisms 915.2.1 Flow Models 925.2.2 Diffusional Deposition 965.2.3 Deposition by Interception 985.2.4 Deposition due to Inertial Impaction 995.2.5 Gravitational Deposition 1005.2.6 Electrostatic Deposition 1005.3 Factors Affecting Efficiency 1045.3.1 Particle Rebound 1045.3.2 Particle Loading 1065.4 Filter Randomness 1095.5 Applications 1095.6 Conclusions 110Nomenclature 110References 1136. Remote Sensing of Atmospheric Aerosols 119Sagnik Dey and Sachchida Nand Tripathi6.1 Introduction 1196.2 Surface-Based Remote Sensing 1206.2.1 Passive Remote Sensing 1206.2.2 Active Remote Sensing 1266.3 Satellite-Based Remote Sensing 1266.3.1 Passive Remote Sensing 1276.3.2 Active Spaceborne Lidar 1356.3.3 Applications of Satellite-Based Aerosol Products 1366.4 Summary and Future Requirements 141Acknowledgements 142References 1427. Atmospheric Particle Nucleation 153Mikko Sipilä, Katrianne Lehtipalo, and Markku Kulmala7.1 General Relevance 1537.2 Detection of Atmospheric Nanoparticles 1567.2.1 Condensation Particle Counting 1567.2.2 Electrostatic Methods 1587.2.3 Mass Spectrometric Methods for Cluster Detection 1607.3 Atmospheric Observations of New Particle Formation 1637.3.1 Nucleation 1637.3.2 Growth 1657.4 Laboratory Experiments 1667.4.1 Sulfuric Acid Nucleation 1667.4.2 Hunt for Compound X 1687.5 Concluding Remarks and Future Challenges 169References 1708. Atmospheric Aerosols and Climate Impacts 181Maria Kanakidou8.1 Introduction 1818.2 Global Aerosol Distributions 1818.3 Aerosol Climate Impacts 1828.4 Simulations of Global Aerosol Distributions 1868.5 Extinction of Radiation by Aerosols (Direct Effect) 1908.5.1 Aerosol Optical Depth and Direct Radiative Forcing of Aerosol Components 1938.6 Aerosols and Clouds (Indirect Effect) 1948.6.1 How Aerosols Become CCNs and Grow into Cloud Droplets 1958.7 Radiative Forcing Estimates 2008.8 The Way Forward 203References 2039. Air Pollution and Health and the Role of Aerosols 207Pat Goodman and Otto Hänninen9.1 Background 2079.2 Size Fractions 2089.3 Which Pollution Particle Sizes Are Important? 2099.4 What Health Outcomes Are Associated with Exposure to Air Pollution? 2099.5 Sources of Atmospheric Aerosols 2109.6 Particle Deposition in the Lungs 2109.7 Aerosol Interaction Mechanisms in the Human Body 2119.8 Human Respiratory Outcomes and Aerosol Exposure 2159.9 Cardiovascular Outcomes and Aerosol Exposure 2159.10 Conclusions and Recommendations 216References 21610. Pharmaceutical Aerosols and Pulmonary Drug Delivery 221Darragh Murnane, Victoria Hutter, and Marie Harang10.1 Introduction 22110.2 Pharmaceutical Aerosols in Disease Treatment 22310.2.1 Asthma 22310.2.2 Chronic Obstructive Pulmonary Disease 22410.2.3 Cystic Fibrosis 22410.2.4 Respiratory Tract Infection 22510.2.5 Beyond the Lung: Systemic Drug Delivery 22510.3 Aerosol Physicochemical Properties of Importance in Lung Deposition 22610.4 The Fate of Inhaled Aerosol Particles in the Lung 22810.4.1 Paracellular Transport 22910.4.2 Transcellular Transport 22910.4.3 Carrier-Mediated Transport 23010.4.4 Models for Determining the Fate of Inhaled Aerosols 23110.5 Production of Inhalable Particles 23310.5.1 Particle Attrition and Milling 23310.5.2 Constructive Particle Production 23510.6 Aerosol Generation and Delivery Systems for Pulmonary Therapy 23710.6.1 Nebulised Disease Therapies 23710.6.2 Pressurised Metered-Dose Inhaler Systems 24110.6.3 Dry-Powder Inhalation 24810.6.4 Advancing Drug-Delivery Strategies 25210.7 Product Performance Testing 25310.7.1 Total-Emitted-Dose Testing 25310.7.2 Aerodynamic Particle Size Determination: Inertial Impaction Analysis 25310.8 Conclusion and Outlook 255References 25511. Bioaerosols and Hospital Infections 271Ka man Lai, Zaheer Ahmad Nasir, and Jonathon Taylor11.1 The Importance of Bioaerosols and Infections 27111.2 Bioaerosol-Related Infections in Hospitals 27211.3 Bioaerosol Properties and Deposition in Human Respiratory Systems 27511.4 Chain of Infection and Infection Control in Hospitals 27511.5 Application of Aerosol Science and Technology in Infection Control 27711.5.1 Understanding Hospital Aerobiology and Infection Control 27711.5.2 Bioaerosol Experiments and Models 28011.5.3 Numerical Analysis of Particle Dispersion in Hospitals 28111.5.4 Air-Cleaning Technologies 28211.6 Conclusion 285References 28512. Nanostructured Material Synthesis in the Gas Phase 291Peter V. Pikhitsa and Mansoo Choi12.1 Introduction 29112.2 Aerosol-Based Synthesis 29212.3 Flame Synthesis 29212.4 Flame and Laser Synthesis 29912.5 Laser-Induced Synthesis 30212.6 Metal-Powder Combustion 30912.7 Spark Discharge 31312.8 Assembling Useful Nanostructures 31412.9 Conclusions 322References 32313. The Safety of Emerging Inorganic and Carbon Nanomaterials 327L. Reijnders13.1 Introduction 32713.2 Human Health and Inhaled Persistent Engineered Inorganic and Carbon Nanomaterials 33013.3 Human Health Hazards and Risks Linked to the Ingestion of Persistent Inorganic Nanomaterials 33313.4 Ecotoxicity of Persistent Inorganic and Carbon Nanomaterials 33513.5 Conclusion 336References 33614. Environmental Health in Built Environments 345Zaheer Ahmad Nasir14.1 Environmental Hazards and Built Environments 34514.2 Particulate Contaminants 34814.2.1 Transport and Behaviour of Particles in Built Environments 34914.3 Gas Contaminants 35114.3.1 Biological Hazards 35114.3.2 Physical Hazards 35714.3.3 Ergonomic Hazards 35814.3.4 Ventilation and Environmental Hazards 35914.3.5 Energy-Efficient Built Environments, Climate Change and Environmental Health 361References 36215. Particle Emissions from Vehicles 369Jonathan Symonds15.1 Introduction 36915.2 Engine Concepts and Technologies 37015.2.1 Air–Fuel Mixture 37015.2.2 Spark-Ignition Engines 37115.2.3 Compression-Ignition Engines 37215.2.4 Two-Stroke Engines 37215.2.5 Gas-Turbine Engines 37315.3 Particle Formation 37315.3.1 In-Cylinder Formation 37315.3.2 Evolution in the Exhaust and Aftertreatment Systems 37515.3.3 Noncombustion Particle Sources 37515.3.4 Evolution in the Environment 37615.4 Impact of Vehicle Particle Emissions 37615.4.1 Health and Environmental Effects 37615.4.2 Legislation 37615.5 Sampling and Measurement Techniques 37815.5.1 Sample Handling 37815.5.2 Mass Measurement 37915.5.3 Solid-Particle-Number Measurement 38015.5.4 Sizing Techniques 38215.5.5 Morphology Determination 38215.6 Amelioration Techniques 38515.6.1 Fuel Composition 38515.6.2 Control by Engine Design and Calibration 38515.6.3 Particulate Filters 386Acknowledgements 388References 38816. Movement of Bioaerosols in the Atmosphere and the Consequences for Climate and Microbial Evolution 393Cindy E. Morris, Christel Leyronas, and Philippe C. Nicot16.1 Introduction 39316.2 Emission: Launch into the Atmosphere 39516.2.1 Active Release 39716.2.2 Passive Release 39716.2.3 Quantifying Emissions 39816.3 Transport in the Earth’s Boundary Layer 39916.3.1 Motors of Transport 39916.3.2 Quantifying Near-Surface Flux 40016.4 Long-Distance Transport: From the Boundary Layer into the Free Troposphere 40416.4.1 Scale of Horizontal Long-Distance Transport 40416.4.2 Altitude of Long-Distance Transport 40516.5 Interaction of Microbial Aerosols with Atmospheric Processes 40616.6 Implications of Aerial Transport for Microbial Evolutionary History 407References 41017. Disinfection of Airborne Organisms by Ultraviolet-C Radiation and Sunlight 417Jana S. Kesavan and Jose-Luis Sagripanti17.1 Introduction 41717.2 UV Radiation 41817.3 Sunlight 41917.4 Selected Organisms 42117.4.1 Bacterial Endospores 42117.4.2 Vegetative Bacteria 42217.4.3 Viruses 42317.5 Effects of UV Light on Aerosolized Organisms 42317.5.1 Cell Damage Caused By UV Radiation 42317.5.2 Photorepair 42417.5.3 Typical Survival Curve for UV Exposure 42517.5.4 The UV Rate Constant 42717.5.5 RH and Temperature Effects 42817.5.6 Bacterial Clusters 42917.6 Disinfection of Rooms Using UV-C Radiation 42917.7 Sunlight Exposure Studies 43017.8 Testing Considerations 43117.8.1 Test Methodology in Our Laboratory 43217.9 Discussion 435References 43518. Radioactive Aerosols: Tracers of Atmospheric Processes 441Katsumi Hirose18.1 Introduction 44118.2 Origin of Radioactive Aerosols 44218.2.1 Natural Radionuclides 44218.2.2 Anthropogenic Radionuclides 44418.3 Tracers of Atmospheric Processes 44618.3.1 Transport of Radioactive Aerosols 44618.3.2 Dry Deposition 44818.3.3 Wet Deposition 44918.3.4 Resuspension 45018.3.5 Other Processes 45218.3.6 Application of Multitracers 45218.3.7 Atmospheric Residence Time of Radioactive Aerosols 45418.4 Tracer of Environmental Change 45718.5 Conclusion 460References 461Index 469

IAN COLBECK, University of Essex, UK MIHALIS LAZARIDIS, Technical University of Crete, Greece

• List of Contributors xiiiPreface xv1. Introduction 1Mihalis Lazaridis and Ian Colbeck1.1 Introduction 11.2 Size and Shape 51.3 Size Distribution 61.4 Chemical Composition 101.5 Measurements and Sampling 11References 122. Aerosol Dynamics 15Mihalis Lazaridis and Yannis Drossinos2.1 Introduction 152.2 General Dynamic Equation 172.2.1 Discrete Particle Size Distribution 182.2.2 Continuous Particle Size Distribution 192.3 Nucleation: New Particle Formation 192.3.1 Classical Nucleation Theory 202.3.2 Multicomponent Nucleation 222.3.3 Heterogeneous Nucleation 232.3.4 Atmospheric Nucleation 242.4 Growth by Condensation 262.5 Coagulation and Agglomeration 272.5.1 Brownian Coagulation 282.5.2 Agglomeration 282.6 Deposition Mechanisms 322.6.1 Stokes Law 322.6.2 Gravitational Settling 322.6.3 Deposition by Diffusion 342.6.4 Deposition by Impaction 342.6.5 Phoretic Effects 342.6.6 Atmospheric Aerosol Deposition 352.6.7 Deposition in the Human Respiratory Tract 362.7 Resuspension 382.7.1 Monolayer Resuspension 382.7.2 Multilayer Resuspension 39References 413. Recommendations for Aerosol Sampling 45Alfred Wiedensohler, Wolfram Birmili, Jean-Philippe Putaud, and John Ogren3.1 Introduction 453.2 Guidelines for Standardized Aerosol Sampling 463.2.1 General Recommendations 463.2.2 Standardization of Aerosol Inlets 473.2.3 Humidity Control 493.3 Concrete Sampling Configurations 533.3.1 General Aspects of Particle Motion 533.3.2 Laminar Flow Sampling Configuration 543.3.3 Turbulent Flow Sampling Configuration 553.4 Artifact-Free Sampling for Organic Carbon Analysis 57Acknowledgements 59References 594. Aerosol Instrumentation 61Da-Ren Chen and David Y. H. Pui4.1 Introduction 614.2 General Strategy 624.3 Aerosol Sampling Inlets and Transport 634.4 Integral Moment Measurement 644.4.1 Total Number Concentration Measurement: Condensation Particle Counter (CPC) 654.4.2 Total Mass Concentration Measurement: Quartz-Crystal Microbalance (QCM) and Tapered-Element Oscillating Microbalance (TEOM) 664.4.3 Light-Scattering Photometers and Nephelometers 674.5 Particle Surface Area Measurement 684.6 Size-Distribution Measurement 704.6.1 Techniques based on Particle–Light Interaction 704.6.2 Techniques based on Particle Inertia 714.6.3 Techniques based on Particle Electrical Mobility 744.6.4 Techniques based on Particle Diffusion 774.7 Chemical Composition Measurement 784.8 Conclusion 80References 825. Filtration Mechanisms 89Sarah Dunnett5.1 Introduction 895.2 Deposition Mechanisms 915.2.1 Flow Models 925.2.2 Diffusional Deposition 965.2.3 Deposition by Interception 985.2.4 Deposition due to Inertial Impaction 995.2.5 Gravitational Deposition 1005.2.6 Electrostatic Deposition 1005.3 Factors Affecting Efficiency 1045.3.1 Particle Rebound 1045.3.2 Particle Loading 1065.4 Filter Randomness 1095.5 Applications 1095.6 Conclusions 110Nomenclature 110References 1136. Remote Sensing of Atmospheric Aerosols 119Sagnik Dey and Sachchida Nand Tripathi6.1 Introduction 1196.2 Surface-Based Remote Sensing 1206.2.1 Passive Remote Sensing 1206.2.2 Active Remote Sensing 1266.3 Satellite-Based Remote Sensing 1266.3.1 Passive Remote Sensing 1276.3.2 Active Spaceborne Lidar 1356.3.3 Applications of Satellite-Based Aerosol Products 1366.4 Summary and Future Requirements 141Acknowledgements 142References 1427. Atmospheric Particle Nucleation 153Mikko Sipilä, Katrianne Lehtipalo, and Markku Kulmala7.1 General Relevance 1537.2 Detection of Atmospheric Nanoparticles 1567.2.1 Condensation Particle Counting 1567.2.2 Electrostatic Methods 1587.2.3 Mass Spectrometric Methods for Cluster Detection 1607.3 Atmospheric Observations of New Particle Formation 1637.3.1 Nucleation 1637.3.2 Growth 1657.4 Laboratory Experiments 1667.4.1 Sulfuric Acid Nucleation 1667.4.2 Hunt for Compound X 1687.5 Concluding Remarks and Future Challenges 169References 1708. Atmospheric Aerosols and Climate Impacts 181Maria Kanakidou8.1 Introduction 1818.2 Global Aerosol Distributions 1818.3 Aerosol Climate Impacts 1828.4 Simulations of Global Aerosol Distributions 1868.5 Extinction of Radiation by Aerosols (Direct Effect) 1908.5.1 Aerosol Optical Depth and Direct Radiative Forcing of Aerosol Components 1938.6 Aerosols and Clouds (Indirect Effect) 1948.6.1 How Aerosols Become CCNs and Grow into Cloud Droplets 1958.7 Radiative Forcing Estimates 2008.8 The Way Forward 203References 2039. Air Pollution and Health and the Role of Aerosols 207Pat Goodman and Otto Hänninen9.1 Background 2079.2 Size Fractions 2089.3 Which Pollution Particle Sizes Are Important? 2099.4 What Health Outcomes Are Associated with Exposure to Air Pollution? 2099.5 Sources of Atmospheric Aerosols 2109.6 Particle Deposition in the Lungs 2109.7 Aerosol Interaction Mechanisms in the Human Body 2119.8 Human Respiratory Outcomes and Aerosol Exposure 2159.9 Cardiovascular Outcomes and Aerosol Exposure 2159.10 Conclusions and Recommendations 216References 21610. Pharmaceutical Aerosols and Pulmonary Drug Delivery 221Darragh Murnane, Victoria Hutter, and Marie Harang10.1 Introduction 22110.2 Pharmaceutical Aerosols in Disease Treatment 22310.2.1 Asthma 22310.2.2 Chronic Obstructive Pulmonary Disease 22410.2.3 Cystic Fibrosis 22410.2.4 Respiratory Tract Infection 22510.2.5 Beyond the Lung: Systemic Drug Delivery 22510.3 Aerosol Physicochemical Properties of Importance in Lung Deposition 22610.4 The Fate of Inhaled Aerosol Particles in the Lung 22810.4.1 Paracellular Transport 22910.4.2 Transcellular Transport 22910.4.3 Carrier-Mediated Transport 23010.4.4 Models for Determining the Fate of Inhaled Aerosols 23110.5 Production of Inhalable Particles 23310.5.1 Particle Attrition and Milling 23310.5.2 Constructive Particle Production 23510.6 Aerosol Generation and Delivery Systems for Pulmonary Therapy 23710.6.1 Nebulised Disease Therapies 23710.6.2 Pressurised Metered-Dose Inhaler Systems 24110.6.3 Dry-Powder Inhalation 24810.6.4 Advancing Drug-Delivery Strategies 25210.7 Product Performance Testing 25310.7.1 Total-Emitted-Dose Testing 25310.7.2 Aerodynamic Particle Size Determination: Inertial Impaction Analysis 25310.8 Conclusion and Outlook 255References 25511. Bioaerosols and Hospital Infections 271Ka man Lai, Zaheer Ahmad Nasir, and Jonathon Taylor11.1 The Importance of Bioaerosols and Infections 27111.2 Bioaerosol-Related Infections in Hospitals 27211.3 Bioaerosol Properties and Deposition in Human Respiratory Systems 27511.4 Chain of Infection and Infection Control in Hospitals 27511.5 Application of Aerosol Science and Technology in Infection Control 27711.5.1 Understanding Hospital Aerobiology and Infection Control 27711.5.2 Bioaerosol Experiments and Models 28011.5.3 Numerical Analysis of Particle Dispersion in Hospitals 28111.5.4 Air-Cleaning Technologies 28211.6 Conclusion 285References 28512. Nanostructured Material Synthesis in the Gas Phase 291Peter V. Pikhitsa and Mansoo Choi12.1 Introduction 29112.2 Aerosol-Based Synthesis 29212.3 Flame Synthesis 29212.4 Flame and Laser Synthesis 29912.5 Laser-Induced Synthesis 30212.6 Metal-Powder Combustion 30912.7 Spark Discharge 31312.8 Assembling Useful Nanostructures 31412.9 Conclusions 322References 32313. The Safety of Emerging Inorganic and Carbon Nanomaterials 327L. Reijnders13.1 Introduction 32713.2 Human Health and Inhaled Persistent Engineered Inorganic and Carbon Nanomaterials 33013.3 Human Health Hazards and Risks Linked to the Ingestion of Persistent Inorganic Nanomaterials 33313.4 Ecotoxicity of Persistent Inorganic and Carbon Nanomaterials 33513.5 Conclusion 336References 33614. Environmental Health in Built Environments 345Zaheer Ahmad Nasir14.1 Environmental Hazards and Built Environments 34514.2 Particulate Contaminants 34814.2.1 Transport and Behaviour of Particles in Built Environments 34914.3 Gas Contaminants 35114.3.1 Biological Hazards 35114.3.2 Physical Hazards 35714.3.3 Ergonomic Hazards 35814.3.4 Ventilation and Environmental Hazards 35914.3.5 Energy-Efficient Built Environments, Climate Change and Environmental Health 361References 36215. Particle Emissions from Vehicles 369Jonathan Symonds15.1 Introduction 36915.2 Engine Concepts and Technologies 37015.2.1 Air–Fuel Mixture 37015.2.2 Spark-Ignition Engines 37115.2.3 Compression-Ignition Engines 37215.2.4 Two-Stroke Engines 37215.2.5 Gas-Turbine Engines 37315.3 Particle Formation 37315.3.1 In-Cylinder Formation 37315.3.2 Evolution in the Exhaust and Aftertreatment Systems 37515.3.3 Noncombustion Particle Sources 37515.3.4 Evolution in the Environment 37615.4 Impact of Vehicle Particle Emissions 37615.4.1 Health and Environmental Effects 37615.4.2 Legislation 37615.5 Sampling and Measurement Techniques 37815.5.1 Sample Handling 37815.5.2 Mass Measurement 37915.5.3 Solid-Particle-Number Measurement 38015.5.4 Sizing Techniques 38215.5.5 Morphology Determination 38215.6 Amelioration Techniques 38515.6.1 Fuel Composition 38515.6.2 Control by Engine Design and Calibration 38515.6.3 Particulate Filters 386Acknowledgements 388References 38816. Movement of Bioaerosols in the Atmosphere and the Consequences for Climate and Microbial Evolution 393Cindy E. Morris, Christel Leyronas, and Philippe C. Nicot16.1 Introduction 39316.2 Emission: Launch into the Atmosphere 39516.2.1 Active Release 39716.2.2 Passive Release 39716.2.3 Quantifying Emissions 39816.3 Transport in the Earth’s Boundary Layer 39916.3.1 Motors of Transport 39916.3.2 Quantifying Near-Surface Flux 40016.4 Long-Distance Transport: From the Boundary Layer into the Free Troposphere 40416.4.1 Scale of Horizontal Long-Distance Transport 40416.4.2 Altitude of Long-Distance Transport 40516.5 Interaction of Microbial Aerosols with Atmospheric Processes 40616.6 Implications of Aerial Transport for Microbial Evolutionary History 407References 41017. Disinfection of Airborne Organisms by Ultraviolet-C Radiation and Sunlight 417Jana S. Kesavan and Jose-Luis Sagripanti17.1 Introduction 41717.2 UV Radiation 41817.3 Sunlight 41917.4 Selected Organisms 42117.4.1 Bacterial Endospores 42117.4.2 Vegetative Bacteria 42217.4.3 Viruses 42317.5 Effects of UV Light on Aerosolized Organisms 42317.5.1 Cell Damage Caused By UV Radiation 42317.5.2 Photorepair 42417.5.3 Typical Survival Curve for UV Exposure 42517.5.4 The UV Rate Constant 42717.5.5 RH and Temperature Effects 42817.5.6 Bacterial Clusters 42917.6 Disinfection of Rooms Using UV-C Radiation 42917.7 Sunlight Exposure Studies 43017.8 Testing Considerations 43117.8.1 Test Methodology in Our Laboratory 43217.9 Discussion 435References 43518. Radioactive Aerosols: Tracers of Atmospheric Processes 441Katsumi Hirose18.1 Introduction 44118.2 Origin of Radioactive Aerosols 44218.2.1 Natural Radionuclides 44218.2.2 Anthropogenic Radionuclides 44418.3 Tracers of Atmospheric Processes 44618.3.1 Transport of Radioactive Aerosols 44618.3.2 Dry Deposition 44818.3.3 Wet Deposition 44918.3.4 Resuspension 45018.3.5 Other Processes 45218.3.6 Application of Multitracers 45218.3.7 Atmospheric Residence Time of Radioactive Aerosols 45418.4 Tracer of Environmental Change 45718.5 Conclusion 460References 461Index 469