H. Van Dop - Böcker

In 1949, when the North Atlantic Treaty was ratified, one of its articles explicitly noted '1hat member countries should contribute towards the further development of peaceful and friendly international relations." Specific problems related to the human environment were addressed by the Committee of Challenges of Modern Society (CCMS) of NATO, established in 1969. This provided a framework within which a series of International Technical Meetings (ITMs) on Air Pollution Modelling has been held. This volume documents the proceedings of the 18th meeting in this series. Science, like the arts and sports, provides an ideal vehicle for "developing peaceful and friendly international relations". National boundaries have never been barriers to the movement of air pollution, and fortunately this has also proved true of scientists studying the transport of air pollution. It is thus satisfying to record that since the mid-seventies it has been commonplace to find Eastern European scientists among attendees at the ITMs which have (in a very modest way) participated in a precursor to the process which has led to historical changes in Europe and which will undoubtedly lead to a tremendous increase in personal and intellectual exchange on a worldwide basis.

The interest in air pollution modelling has shown substantial growth over the last five years. This was particularly evident by the increasing number of participants attending the NATO/CCMS International Technical Meetings on Air Pollution modelling and its Application. At the last meeting 118 papers and posters were selected from an abundance of submitted abstracts divided over five modelling topics: (i) model assessment and verification, including policy applications, (ii) air pollution modelling in coastal areas with emphasis on the mediterranean region, (iii) accidental atmospheric releases, including warning systems and regulations, (iv) modelling of global and long-range transport and (v) new developments in turbulent diffusion. A round-table discussion chaired by John Irwin (USA) and Jan Kretzschmar (Belgium) on the harmonization of air pollution models was attended by more than 50 scientists and is reported in these proceedings. The opening paper addressed the main issue of this conference: modelling over complex terrain. Of particular interest were coastal areas where the surface inhomogeneities introduce small-scale circulation and varying atmospheric stability, often combined with a complex topography. As the conference was located on the beautiful island of Crete, problems faced by the host nation, particularly Athens and its environs were obvious examples for consideration. These together with other regions with similar geographical features were addressed. Heavily populated and industrialized as they often are, air quality is generally poor there and emission regulations are desired. Obviously, a major task of air pollution dispersion modelling is to assist policy makers in formulating sensible regulations.

The protection of the environment is one of the most important problems facing us today. Reliable and robust strategies for keeping pollution caused by harmful chemicals under safe levels have to be developed and used routinely. Large mathematical models, incorporating all important physical and chemical processes, can solve this task, but the computational burden is huge. The papers presented here describe some of the difficult problems that have to be solved during the development of large scale air pollution models, and different ways to solve them. The work involves combined research by specialists in the fields of environmental modelling, numerical analysis and scientific computing. Further, if models are to run in real time (which may be vital in the case of accidental hazardous releases), then new and efficient methods that harness the potential power of parallel supercomputers must be developed, so that actual computing speed starts to approach the maximum available performance. The articles should be understandable by specialists in the field of air pollution modelling, as well as specialists in the many other related areas.

The interest in air pollution modelling has shown substantial growth over the last five years. This was particularly evident by the increasing number of participants attending the NATO/CCMS International Technical Meetings on Air Pollution modelling and its Application. At the last meeting 118 papers and posters were selected from an abundance of submitted abstracts divided over five modelling topics: (i) model assessment and verification, including policy applications, (ii) air pollution modelling in coastal areas with emphasis on the mediterranean region, (iii) accidental atmospheric releases, including warning systems and regulations, (iv) modelling of global and long-range transport and (v) new developments in turbulent diffusion. A round-table discussion chaired by John Irwin (USA) and Jan Kretzschmar (Belgium) on the harmonization of air pollution models was attended by more than 50 scientists and is reported in these proceedings. The opening paper addressed the main issue of this conference: modelling over complex terrain. Of particular interest were coastal areas where the surface inhomogeneities introduce small-scale circulation and varying atmospheric stability, often combined with a complex topography. As the conference was located on the beautiful island of Crete, problems faced by the host nation, particularly Athens and its environs were obvious examples for consideration. These together with other regions with similar geographical features were addressed. Heavily populated and industrialized as they often are, air quality is generally poor there and emission regulations are desired. Obviously, a major task of air pollution dispersion modelling is to assist policy makers in formulating sensible regulations.

In 1949, when the North Atlantic Treaty was ratified, one of its articles explicitly noted '1hat member countries should contribute towards the further development of peaceful and friendly international relations." Specific problems related to the human environment were addressed by the Committee of Challenges of Modern Society (CCMS) of NATO, established in 1969. This provided a framework within which a series of International Technical Meetings (ITMs) on Air Pollution Modelling has been held. This volume documents the proceedings of the 18th meeting in this series. Science, like the arts and sports, provides an ideal vehicle for "developing peaceful and friendly international relations". National boundaries have never been barriers to the movement of air pollution, and fortunately this has also proved true of scientists studying the transport of air pollution. It is thus satisfying to record that since the mid-seventies it has been commonplace to find Eastern European scientists among attendees at the ITMs which have (in a very modest way) participated in a precursor to the process which has led to historical changes in Europe and which will undoubtedly lead to a tremendous increase in personal and intellectual exchange on a worldwide basis.