Proceedings of the Concawe seminar on atmospheric emissions and their effects on the environment in Europe with particular reference to the role of hydrocarbons

Report no. 86/61: Forest die-back on a large scale in Europe and North America has led to renewed investigations into the role of air pollution and its ecological impact.

Essential elements in the extremely complicated process, from emissions via transport, chemical transformation and deposition to supposed effect, are the dispersion and deposition of the pollutants. A large proportion of the pollutants are able to travel over a considerable distance, of the order of 1000 km. This paper indicates how dispersion over these distances can be described.

A summary is given of box models, trajectory models and grid models. The latter models contain the most detailed description of the atmospheric transport and deposition process. However, they require an enormous amount of meteorological information. Also, computer time and storage requirements are excessive. Finally, the process of deposition, accompanied or not by precipitation is discussed.