Expanded and updated with new findings and new features * New chapter on Global Climate providing a self-contained treatment of climate forcing, feedbacks, and climate sensitivity * New chapter on Atmospheric Organic Aerosols and new treatment of the statistical method of Positive Matrix Factorization * Updated treatments of physical meteorology, atmospheric nucleation, aerosol-cloud relationships, chemistry of biogenic hydrocarbons * Each topic developed from the fundamental science to the point of application to real-world problems * New problems at an introductory level to aid in classroom teaching Preface to the Third Edition Preface to the First Edition I The Atmosphere and Its Constituents 1 The Atmosphere 1.1 History and Evolution of the Earth s Atmosphere 1.2 Climate 1.3 The Layers of the Atmosphere 1.4 Pressure in the Atmosphere 1.4.1 Units of Pressure 1.4.2 Variation of Pressure with Height in the Atmosphere 1.5 Temperature in the Atmosphere 1.6 Expressing the Amount of a Substance in the Atmosphere 1.7 Airborne Particles 1.8 Spatial and Temporal Scales of Atmospheric Processes Problems References 2 Atmospheric Trace Constituents 2.1 Atmospheric Lifetime 2.2 Sulfur-Containing Compounds 2.3 Nitrogen-Containing Compounds 2.4 Carbon-Containing Compounds 2.5 Halogen-Containing Compounds 2.6 Atmospheric Ozone 2.7 Particulate Matter (Aerosols) 2.8 Mercury 2.9 Emission Inventories Appendix 2.1 Air Pollution Legislation Appendix 2.2 Hazardous Air Pollutants (Air Toxics) Problems References II Atmospheric Chemistry 3 Chemical Kinetics 3.1 Order of Reaction 3.2 Theories of Chemical Kinetics 3.3 The Pseudo-Steady-State Approximation 3.4 Reactions of Excited Species 3.5 Termolecular Reactions 3.6 Chemical Families 3.7 Gas Surface Reactions Appendix 3 Free Radicals Problems References 4 Atmospheric Radiation and Photochemistry 4.1 Radiation 4.2 Radiative Flux in the Atmosphere 4.3 Beer Lambert Law and Optical Depth 4.4 Actinic Flux 4.5 Atmospheric Photochemistry 4.6 Absorption of Radiation by Atmospheric Gases 4.7 Absorption by O2 and O3 4.8 Photolysis Rate as a Function of Altitude 4.9 Photodissociation of O3 to Produce O and O(1D) 4.10 Photodissociation of NO2 Problems References 5 Chemistry of the Stratosphere 5.1 Overview of Stratospheric Chemistry 5.2 Chapman Mechanism 5.3 Nitrogen Oxide Cycles 5.4 HOx Cycles 5.5 Halogen Cycles 5.6 Reservoir Species and Coupling of the Cycles 5.7 Ozone Hole 5.8 Heterogeneous (Nonpolar) Stratospheric Chemistry 5.9 Summary of Stratospheric Ozone Depletion 5.10 Transport and Mixing in the Stratosphere 5.11 Ozone Depletion Potential Problems References 6 Chemistry of the Troposphere 6.1 Production of Hydroxyl Radicals in the Troposphere 6.2 Basic Photochemical Cycle of NO2, NO, and O3 6.3 Atmospheric Chemistry of Carbon Monoxide 6.4 Atmospheric Chemistry of Methane 6.5 The NOx and NOy Families 6.6 Ozone Budget of the Troposphere and Role of NOx 6.7 Tropospheric Reservoir Molecules 6.8 Relative Roles of VOC and NOx in Ozone Formation 6.9 Simplified Organic/NOx Chemistry 6.10 Chemistry of Nonmethane Organic Compounds in the Troposphere 6.11 Atmospheric Chemistry of Biogenic Hydrocarbons 6.12 Atmospheric Chemistry of Reduced Nitrogen Compounds 6.13 Atmospheric Chemistry (Gas Phase) of Sulfur Compounds 6.14 Tropospheric Chemistry of Halogen Compounds 6.15 Atmospheric Chemistry of Mercury Appendix 6 Organic Functional Groups Problems References 7 Chemistry of the Atmospheric Aqueous Phase 7.1 Liquid Water in the Atmosphere 7.2 Absorption Equilibria and Henry s Law 7.3 Aqueous-Phase Chemical Equilibria 7.4 Aqueous-Phase Reaction Rates 7.5 S(IV) S(VI) Transformation and Sulfur Chemistry 7.6 Dynamic Behavior of Solutions with Aqueous-Phase Chemical Reactions Appendix 7.1 Thermodynamic and Kinetic Data Appendix 7.2 Additional Aqueous-Phase Sulfur Chemistry Appendix 7.3 Aqueous-Phase Nitrite and Nitrate Chemistry Appendix 7.4 Aqueous-Phase Organic Chemistry Appendix 7.5 Oxygen and Hydrogen Chemistry Problems References III Aerosols 8 Properties of the Atmospheric Aerosol 8.1 The Size Distribution Function 8.2 Ambient Aerosol Size Distributions 8.3 Aerosol Chemical Composition 8.4 Spatial and Temporal Variation Problems References 9 Dynamics of Single Aerosol Particles 9.1 Continuum and Noncontinuum Dynamics: The Mean Free Path 9.2 The Drag on a Single Particle: Stokes Law 9.3 Gravitational Settling of an Aerosol Particle 9.4 Motion of an Aerosol Particle in an External Force Field 9.5 Brownian Motion of Aerosol Particles 9.6 Aerosol and Fluid Motion 9.7 Equivalent Particle Diameters Problems References 10 Thermodynamics of Aerosols 10.1 Thermodynamic Principles 10.2 Aerosol Liquid Water Content 10.3 Equilibrium Vapor Pressure over a Curved Surface: The Kelvin Effect 10.4 Thermodynamics of Atmospheric Aerosol Systems 10.5 Aerosol Thermodynamic Models Problems References 11 Nucleation 11.1 Classical Theory of Homogeneous Nucleation: Kinetic Approach 11.2 Classical Homogeneous Nucleation Theory: Constrained Equilibrium Approach 11.3 Recapitulation of Classical Theory 11.4 Experimental Measurement of Nucleation Rates 11.5 Modifications of the Classical Theory and More Rigorous Approaches 11.6 Binary Homogeneous Nucleation 11.7 Binary Nucleation in the H2SO4 H2O System 11.8 Nucleation on an Insoluble Foreign Surface 11.9 Ion-Induced Nucleation 11.10 Atmospheric New Particle Formation Appendix 11 The Law of Mass Action Problems References 12 Mass Transfer Aspects of Atmospheric Chemistry 12.1 Mass and Heat Transfer to Atmospheric Particles 12.2 Mass Transport Limitations in Aqueous-Phase Chemistry 12.3 Mass Transport and Aqueous-Phase Chemistry 12.4 Mass Transfer to Falling Drops 12.5 Characteristic Time for Atmospheric Aerosol Equilibrium Appendix 12 Solution of the Transient Gas-Phase Diffusion Problem Equations (12.4) (12.7) Problems References 13 Dynamics of Aerosol Populations 13.1 Mathematical Representations of Aerosol Size Distributions 13.2 Condensation 13.3 Coagulation 13.4 The Discrete General Dynamic Equation 13.5 The Continuous General Dynamic Equation Appendix 13.1 Additional Mechanisms of Coagulation Appendix 13.2 Solution of (13.73) Problems References 14 Atmospheric Organic Aerosols 14.1 Chemistry of Secondary Organic Aerosol Formation 14.2 Volatility of Organic Compounds 14.3 Idealized Description of Secondary Organic Aerosol Formation 14.4 Gas-Particle Partitioning 14.5 Models of SOA Formation and Evolution 14.6 Primary Organic Aerosol 14.7 The Physical State of Organic Aerosols 14.8 SOA Particle-Phase Chemistry 14.9 Aqueous-Phase Secondary Organic Aerosol Formation 14.10 Estimates of the Global Budget of Atmospheric Organic Aerosol Problems References 15 Interaction of Aerosols with Radiation 15.1 Scattering and Absorption of Light by Small Particles 15.2 Visibility 15.3 Scattering, Absorption, and Extinction Coefficients from Mie Theory 15.4 Calculated Visibility Reduction Based on Atmospheric Data Appendix 15 Calculation of Scattering and Extinction Coefficients by Mie Theory Problems References IV Physical and Dynamic Meteorology, Cloud Physics, and Atmospheric Diffusion 16 Physical and Dynamic Meteorology 16.1 Temperature in the Lower Atmosphere 16.2 Atmospheric Stability 16.3 The Moist Atmosphere 16.4 Basic Conservation Equations for the Atmospheric Surface Layer 16.5 Variation of Wind with Height in the Atmosphere Appendix 16.1 Properties of Water and Water Solutions Appendix 16.2 Derivation of the Basic Equations of Surface Layer Atmospheric Fluid Mechanics Problems References 17 Cloud Physics 17.1 Equilibrium of Water Droplets in the Atmosphere 17.2 Cloud and Fog Formation 17.3 Growth Rate of Individual Cloud Droplets 17.4 Growth of a Droplet Population 17.5 Cloud Condensation Nuclei 17.6 Cloud Processing of Aerosols 17.7 Other Forms of Water in the Atmosphere Appendix 17 Extended Köhler Theory Problems References 18 Atmospheric Diffusion 18.1 Eulerian Approach 18.2 Lagrangian Approach 18.3 Comparison of Eulerian and Lagrangian Approaches 18.4 Equations Governing the Mean Concentration of Species in Turbulence 18.5 Solution of the Atmospheric Diffusion Equation for an Instantaneous Source 18.6 Mean Concentration from Continuous Sources 18.7 Statistical Theory of Turbulent Diffusion 18.8 Summary of Atmospheric Diffusion Theories 18.9 Analytical Solutions for Atmospheric Diffusion: The Gaussian Plume Equation and Others 18.10 Dispersion Parameters in Gaussian Models 18.11 Plume Rise 18.12 Functional Forms of Mean Windspeed and Eddy Diffusivities 18.13 Solutions of the Steady-State Atmospheric Diffusion Equation Appendix 18.1 Further Solutions of Atmospheric Diffusion Problems Appendix 18.2 Analytical Properties of the Gaussian Plume Equation Problems References V Dry and Wet Deposition 19 Dry Deposition 19.1 Deposition Velocity 19.2 Resistance Model for Dry Deposition 19.3 Aerodynamic Resistance 19.4 Quasi-Laminar Resistance 19.5 Surface Resistance 19.6 Measurement of Dry Deposition 19.7 Some Comments on Modeling and Measurement of Dry Deposition Problems References 20 Wet Deposition 20.1 General Representation of Atmospheric Wet Removal Processes 20.2 Below-Cloud Scavenging of Gases 20.3 Precipitation Scavenging of Particles 20.4 In-Cloud Scavenging 20.5 Acid Deposition 20.6 Acid Deposition Process Synthesis Problems References VI The Global Atmosphere, Biogeochemical Cycles, and Climate 21 General Circulation of the Atmosphere 21.1 Hadley Cell 21.2 Ferrell Cell and Polar Cell 21.3 Coriolis Force 21.4 Geostrophic Windspeed 21.5 The Thermal Wind Relation 21.6 Stratospheric Dynamics 21.7 The Hydrologic Cycle Problems References 22 Global Cycles: Sulfur and Carbon 22.1 The Atmospheric Sulfur Cycle 22.2 The Global Carbon Cycle 22.3 Solution for a Steady-State Four-Compartment Model of the Atmosphere Problems References 23 Global Climate 23.1 The Earth s Energy Balance 23.2 Radiative Forcing 23.3 The Greenhouse Effect 23.4 Climate Forcing Agents 23.4.3 Radiative Efficiencies of Greenhouse Gases 23.5 Cosmic Rays and Climate 23.6 Climate Sensitivity 23.7 Simplified Dynamic Description of Climate Forcing and Response 23.8 Climate Feedbacks 23.9 Relative Radiative Forcing Indices 23.10 Atmospheric Chemistry and Climate Change 23.11 Conclusion Problems References 24 Aerosols and Climate 24.1 Scattering Absorbing Model of an Aerosol Layer 24.2 Cooling versus Heating of an Aerosol Layer 24.3 Scattering Model of an Aerosol Layer for a Nonabsorbing Aerosol 24.4 Upscatter Fraction 24.5 Optical Depth and Column Forcing 24.6 Internal and External Mixtures 24.7 Top-of-the-Atmosphere versus Surface Forcing 24.8 Indirect Effects of Aerosols on Climate Problems References VII Chemical Transport Models and Statistical Models 25 Atmospheric Chemical Transport Models 25.1 Introduction 25.2 Box Models 25.3 Three-Dimensional Atmospheric Chemical Transport Models 25.4 One-Dimensional Lagrangian Models 25.5 Other Forms of Chemical Transport Models 25.6 Numerical Solution of Chemical Transport Models 25.7 Model Evaluation 25.8 Response of Organic and Inorganic Aerosols to Changes in Emissions Problems References 26 Statistical Models 26.1 Receptor Modeling Methods 26.2 Chemical Mass Balance (CMB) 26.3 Factor Analysis 26.4 Methods Incorporating Wind Information 26.5 Probability Distributions for Air Pollutant Concentrations 26.6 Estimation of Parameters in the Distributions 26.7 Order Statistics of Air Quality Data 26.8 Exceedances of Critical Levels 26.9 Alternative Forms of Air Quality Standards 26.10 Relating Current and Future Air Pollutant Statistical Distributions Problems References Appendices Appendix A Units and Physical Constants A.1 SI Base Units A.2 SI Derived Units A.3 Fundamental Physical Constants A.4 Properties of the Atmosphere and Water A.5 Units for Representing Chemical Reactions A.6 Concentrations in the Aqueous Phase A.7 Symbols for Concentration References Appendix B Rate Constants of Atmospheric Chemical Reactions References Index