This book provides a unique overview of research methods over the past 25 years assessing critical loads and temporal effects of the deposition of air pollutants. It includes critical load methods and applications addressing acidification, eutrophication and heavy metal pollution of terrestrial and aquatic ecosystems. Applications include examples for each air pollution threat, both at local and regional scale, including Europe, Asia, Canada and the US. The book starts with background information on the effects of the deposition of sulphur, nitrogen and heavy metals and geochemical and biological indicators for risk assessments. The use of those indicators is then illustrated in the assessment of critical loads and their exceedances and in the temporal assessment of air pollution risks. It also includes the most recent developments of assessing critical loads and current and future risks of soil and water chemistry and biodiversity under climate change, with a special focus on nitrogen. The book thus provides a complete overview of the knowledge that is currently used for the scientific support of policies in the field of air pollution control to protect ecosystem services.

Concern about acid deposition, commonly referred to as acid rain, as a widespread pollution problem with severe ecological consequences has heightened public awareness. Many authorities fear that acid deposition may be the worst environmental crisis of our industrialized society because of both the global implications and possible widespread, irreversible damage to lakes, soils, and forested ecosystems. Neither state nor international boundaries are exempt from the transport and deposition of airborne pollutants resulting from local and distant emission sources. The dilemma and debate will continue as long as society requires fossil fuels for its energy needs without regard to emission constraints. This book started as a modest attempt to provide a status report on atmospheric transport, the chemical processes which produce acidifying agents, and resultant ecological and economic consequences. The materials in this book have been substantially revised from those presented at the conference in 1983. It became obvious that additional chapters were required when sudden and profound changes occurring in European forests were reported. It is felt that perhaps such damages could be an early warning to forested ecosystems in the northeastern United States and Canada as well as other places throughout the world. Most importantly, it is essential that gained scientific knowledge be translated into required legislation - a section on Policy Issues was incorporated to address these concerns. It is hoped that the reader will become informed and concerned enough to be involved in ll this IIglobal debate. Donald D. Adams Halter P.

The ocean has absorbed a significant portion of all human-made carbon dioxide emissions. This benefits human society by moderating the rate of climate change, but also causes unprecedented changes to ocean chemistry. Carbon dioxide taken up by the ocean decreases the pH of the water and leads to a suite of chemical changes collectively known as ocean acidification. The long term consequences of ocean acidification are not known, but are expected to result in changes to many ecosystems and the services they provide to society. Ocean Acidification: A National Strategy to Meet the Challenges of a Changing Ocean reviews the current state of knowledge, explores gaps in understanding, and identifies several key findings. Like climate change, ocean acidification is a growing global problem that will intensify with continued CO2 emissions and has the potential to change marine ecosystems and affect benefits to society. The federal government has taken positive initial steps by developing a national ocean acidification program, but more information is needed to fully understand and address the threat that ocean acidification may pose to marine ecosystems and the services they provide. In addition, a global observation network of chemical and biological sensors is needed to monitor changes in ocean conditions attributable to acidification.