1 Introduction.- 1.1 Man and Environment.- 1.2 Technical Chemistry and Ecology.- 2 Basic Chemical and Ecological Principles.- 2.1 Exposure and Effect Criteria of Chemicals.- 2.1.1 Structure-Activity Relationships.- 2.1.1.1 Chemical Structure Descriptors.- 2.1.1.2 Techniques for Defining Structure-Activity Relationships.- 2.1.2 Equilibrium Constants for Chemicals Distribution..- 2.1.2.1 Aggregate State and Related Properties.- 2.1.2.2 Specific Gravity, Molar Mass and Structure.- 2.1.2.3 Melting and Boiling Points.- 2.1.2.4 Vapour Pressure, Vapour Density and Volatility.- 2.1.2.5 Water Solubility.- 2.1.2.6 n-Octanol/Water Partition Coefficient.- 2.1.3 Kinetic Constants for Environmental Processes.- 2.1.3.1 Hydrolysis.- 2.1.3.2 Photolysis.- 2.1.3.3 Oxidation and Reduction.- 2.1.3.4 Biotransformation.- 2.1.3.5 Bioconcentration, Bioaccumulation and Ecological Magnification.- 2.2 Stability of Ecosystems.- 2.2.1 Different Notions of Stability.- 2.2.2 Stability and Diversity of Ecological Communities.- 2.2.2.1 Diversity Analyses.- 2.2.2.2 Ecological Communities as Dissipative Structures.- 2.3 Biota Resilience Versus Chemical Persistence.- 2.3.1 Chemical Persistence.- 2.3.2 Resilience of Natural Biota.- 2.4 Model Ecosystems and Related Definitions of Environmental Toxicity of Chemicals.- 2.4.1 Eco toxicological Tests.- 2.4.2. Comparative Appraisal and Research Needs.- 3 Fluxes of Anthropogenic Chemicals in the Atmosphere.- 3.1 Natural and Anthropogenic Sources of Potential Pollutants.- 3.1.1 Natural Atmospheric Cycles.- 3.1.2. Anthropogenic Air Pollution.- 3.2 Transport and Dispersion.- 3.2.1 General Atmospheric Boundary Conditions of Air Pollution.- 3.2.2 Atmospheric Lapse Rates and Plume Dilution.- 3.2.3 Selected Dispersion Models.- 3.2.3.1 Box Models.- 3.2.3.2 Statistical Models.- 3.2.3.3 Gaussian Dispersion Models.- 3.2.3.4 Grid Models.- 3.2.3.5 Trajectory Models.- 3.3 Physical Transformation Processes.- 3.3.1 Nucleation.- 3.3.2 Coagulation.- 3.3.3 Condensation.- 3.3.4 Rainout and Washout.- 3.4 Chemical Transformation Processes.- 3.4.1 Formation of Free Radicals and Reactive Trace Constituents.- 3.4.2 Sulphate Reactions.- 3.4.3 Nitrate-Forming Reactions.- 3.4.4 Oxidative Chemistry of Organic Pollutants.- 3.4.4.1 Atmospheric Reaction Pathways for Alkanes.- 3.4.4.2 Atmospheric Reaction Pathways for Alkenes.- 3.4.4.3 Atmospheric Chemistry of Aromatics.- 3.5 Deposition.- 3.5.1 Deposition Networks.- 3.5.2 Sampling Procedures.- 3.5.3 Principles of Deposition.- 3.5.3.1 Dry Deposition of Gases.- 3.5.3.2 Dry Deposition of Particles.- 3.5.3.3 Model Concept of Deposition.- 3.5.4 Deposition of Gases.- 3.5.4.1 General Features of Deposition.- 3.5.4.2 Deposition of Acidic Species and Ozone.- 3.5.5 Removal of Air-Borne Metals by Wet and Dry Deposition.- 3.5.5.1 Factors Influencing Total Atmospheric Deposition of Metals.- 3.5.5.2 Deposition Rates and Mechanisms in Deciduous and Coniferous Forests.- 3.5.5.3 Microscale Variability of Deposition in Forests.- 3.5.5.4 Large-Scale Spatial Variability of Atmospheric Removal Processes of Air-Borne Metals.- 3.5.5.5 Deposition Velocities of Metals.- 3.5.6 Deposition Patterns of Hydrocarbons.- 3.5 7 Deposition of Air-Borne Dust.- 4 Fluxes of Chemicals in the Soil-Vegetation Complex.- 4.1 Energy and Water Balances as Boundary Conditions of Chemical Fluxes.- 4.1.1 Energy Balance at the Earth's Surface.- 4.1.1.1 Net Radiation.- 4.1.1.2 Soil Heat Flow.- 4.1.1.3 Sensible Heat Flow in the Lower Atmosphere.- 4.1.1.4 Latent Heat Flux.- 4.1.1.5 Efficiency of Photosynthesis.- 4.1.1.6 Energy Balance of Wet, Dry and Vegetated Surfaces.- 4.1.2 Water Balance of Bare Soil and Vegetation Stands.- 4.1.2.1 Precipitation and Interception.- 4.1.2.2 Infiltration and Surface Runoff.- 4.1.2.3 Deep Drainage.- 4.1.2.4 Change in Soil Water Storage.- 4.1.2.5 Soil Water Potential and Matrix Flow.- 4.2 Impact of Environmental Chemicals on Vegetation.- 4.2.1 Direct Effects of Acid and Basic Deposition and Photo-Chemical Oxidants.- 4.2.1.1 Sulphur Dioxide.- 4.2.1.2 Nitrogen Oxides.- 4.2.1.3 Ammonia.- 4.2.1.4 Photooxidants.- 4.2.1.5 Combined Effects of Pollutant Gases.- 4.2.1.6 Particulate Pollutants.- 4.2.1.7 Combination Effects of Acid Precipitation.- 4.2.2 Indirect Effects of Acidic Precipitation.- 4.2.2.1 Biotic Interactions.- 4.2.2.2 Interactions with Pesticides.- 4.2.2.3 Soil Acidification and Related Effects on Soil-Borne Microorganisms.- 4.2.3 Dynamic Models of Forest Dieback.- 4.2.3.1 Models with Non-Linear Dose-Effect Relationships.- 4.2.3.2 Time-Series Analysis and Mapping.- 4.3 Pollutant Impact on Materials.- 4.3.1 Pollutant Effects.- 4.3.1.1 Corrosion of Metals and Metal Alloys.- 4.3.1.2 Degradation of Inorganic Non-Metallic Materials.- 4.3.1.3 Degradation of Organic Materials.- 4.3.2 Critical Levels of Pollution.- 4.3.3. European Research Programmes on Pollutants Effects and Restoration.- 4.4 Interactions of Environmental Chemicals with Soil and Subsoil.- 4.4.1 Environmental Factors and Chemistry.- 4.4.1.1 Dispersion.- 4.4.1.2 Sorption and Ion Exchange.- 4.4.1.3 Heavy Metals and Organics in Soil.- 4.4.2 Bioavailability and Biotransformation.- 4.4.2.1 Effects of Chemicals on Microorganisms and Soil Fauna.- 4.4.2.2 Chemical Structure and Biodegradation.- 4.4.2.3 Active Microorganisms.- 4.4.3 Chemical Fate Modelling.- 4.4.3.1 Transport Modelling of Dissolved Chemicals.- 4.4.3.2 Immiscible Contaminant Modelling.- 4.4.3.3 Aquatic Equilibrium Modelling.- 4.4.3.4 Regionalized Fate Modelling.- References.