Acidic Precipitation: Sources, Deposition, and Canopy Interactions

Sources of Acids, Bases, and Their Precursors in the Atmosphere.- I. Introduction and Definitions.- II. Sources of Acids.- III. Sources of Acid-Neutralizing Substances (Bases).- IV. Distribution of Atmospheric Acids and Bases.- V. Gas-Aerosol Equilibria and Boundary Layer Mixing.- VI. Summary of Significant Acid-Formation Pathways.- References.- Aerosol Sulfur Association with Aluminum in Eastern North America: Evidence for Solubilization of Atmospheric Trace Metals before Deposition.- I. Statement of the Problem.- II. Approach to the Problem.- III. Results.- IV. Discussion.- References.- Source-Receptor Relationships for Atmospheric Trace Elements in Europe.- I. Introduction.- II. Emission Patterns of Atmospheric Trace Elements in Europe.- III. Long-Range Transport Models for Trace Elements in Europe.- IV. Application of Statistical Methods in Source-Receptor Studies.- V. Recommendations for Further Research.- References.- The History of Atmospheric Deposition of Cd, Hg, and Pb in North America: Evidence from Lake and Peat Bog Sediments.- I. Introduction.- II. Methods.- III. Results.- IV. Summary.- References.- Dry Deposition of Particles and Vapors.- I. Introduction.- II. The Process of Dry Deposition.- III. Wind Tunnel Studies and Semiempirical Models.- IV. Measurement Methods.- V. Dry Deposition Data and Comparison with Model Predictions.- VI. Summary.- References.- Dry Deposition of Sulfur and Nitrogen Oxide Gases to Forest Vegetation.- I. Introduction.- II. Mechanisms of Dry Deposition of Gases.- III. Experimental Measurement of Deposition.- IV. Results of Measurements of Deposition.- V. Dry Deposition and the Response of Forests.- References.- Throughfall Chemistry and Canopy Processing Mechanisms.- I. Introduction.- II. Processes That Control Throughfall Chemistry.- III. Hypothesized and Observed Throughfall Fluxes.- IV. Future Research.- Appendix: Sequential Throughfall Sampling Methods.- References.- Abatement of Atmospheric Emissions in North America: Progress to Date and Promise for the Future.- I. Introduction.- II. Acidic Rain as a Political and Technical Issue.- III. Emission Patterns.- IV. Emission Reduction Approaches for SO2 and NOx.- V. Forecasting Future Emission Trends.- VI. Cost of Emission Reductions.- VII. Policy Options for Reducing Emissions.- References.