This is the first in a new series of publications arlslng out of the work of the Committee on Challenges of Modern Society of the North Atlantic Treaty Organization. The CCMS was established in 1969 with a mandate to examine practical ways of improving the exchange of experience among mem ber nations of the Alliance in the task of creating a better envir onment for their societies. It was charged with considering "spe cific problems of the human environment with the deliberate objec tive of stimulating action by member governments". It may come as a surprise to some that NATO - generally thought of as being an organization devoted solely to matters of defence - should concern itself with the environment at all. But this is to overlook Article 2 of the North Atlantic Treaty of 1949, which expressly provides that member count ries should contribute towards the furt her development of peaceful and friendly internat ional relations by promoting conditions of stability and well being. This concern is reflected in many non-military areas, in addition to the environmental one. I wish the present volume, which has been edited by the Bel gian Prime Minister's Office for Science Policy Programming, every success.

Inhalt
I: Interregional Transport of Air Pollution (Up To Several Hundreds of Kilometers).- 1. Interregional exchanges of air pollution: Model types and applications.- 2. Trajectories as two-dimensional probability fields.- 3. The use of a regional-scale numerical model in addressing certain key air quality issues anticipated in the 1980s.- 4. Probability prediction of the wet deposition of airborne pollution.- 5. The statistics of precipitation scavenging during long range transport.- 6. Air pollution transport over Western Europe; exchanges between Germany and the Netherlands.- 7. A characterization of interregional transport of ozone and precursors into an urban area.- 8. Air quality projections for the Ohio river basin.- 2: Meteorological Parameters for Use in Advanced Air Diffusion Models.- 9. Estimation of turbulence velocity scales in the stable and the unstable boundary layer for dispersion applications.- 10. Meteorological input for a three dimensional medium range air quality model.- 11. Interest of an atmospheric meso-scale model for air pollution transport studies over medium distances.- 12. A mass consistent wind field model over the Mid-Rhine Valley.- 13. A mesoscale numerical model of atmospheric flow over the Alsace plain.- 14. The application of a stochastic wind model to the meteorology of North-West England.- 15. Atmospheric circulation on the regional scale and isentropic trajectories as support to the long range transport (LRT) of air pollution.- 16. Diffusivity profiles deduced from synoptic data.- 17. Wind velocity variances in the atmospheric boundary layer.- 18. Estimation of mesoscale and local-scale roughness for atmospheric transport modeling.- 19. A convective plume model for PBL dispersion.- 20. Numerical modeling of stack plumes within a city environment at distances of several kilometres downstream.- 21. Results of Lidar measurements of atmospheric barrier layers.- 22. Effects of release height on ?y and ?z in daytime conditions.- 23. Dispersion near to a tall stack.- 24. A statistical approach for estimating atmospheric stability classes from near-ground observations.- 25. Net radiation estimated from standard meteorological data.- 26. Estimation of the sensible heat flux from standard meteorological data for stability calculations during daytime.- 3: Advanced Techniques in Air Pollution Modeling to Take Into Account Complex Terrain, Heavy Gases and Light Wind Conditions.- 27. A comparison of finite difference schemes, describing the two-dimensional advection equation.- 28. A comparison of some plume dispersion predictions with field measurements.- 29. Model investigations of spreading of heavy gases released from an instantaneous volume source at the ground.- 30. Physical modeling of forty cubic meter LNG spills at China Lake, California.- 31. The accidental release of dense flammable and toxic gases from pressurized containment - transition from pressure driven to gravity driven phase.- 32. Entrainment through the top of a heavy gas cloud.- 33. Physical simulation of dispersion in complex terrain and valley drainage flow situations.- 34. Analysis and simulation of local circulations and air pollution over a coastal, complex site.- 35. A new gaussian puff algorithm for non-homogeneous, nonstationary dispersion in complex terrain.- 36. Impact study in complex terrain.- 37. Conversion rate of nitrogen oxides in a polluted atmosphere.- 4: Forecasting Of Polluant Concentration Under Episodic Conditions.- 38. Forecasting of fumigation episodes in the Po Valley.- 39. Numerical computation of high air pollutionlevels.- 40. Application of a photochemical dispersion model to the Netherlands and its surroundings.- 41. An application of a pollution episode predictor derived from a K-theory model.- 42. Forecasting of pollutant concentration under episode conditions..- 5: Regulatory Applications.- 43. An application of the empirical kinetic modeling approach (EKMA) to the Cologne area.- 44. Air pollution impact calculated and measured during licensing procedures.- 45. The regulatory implications of using airport meteorological data instead of onsite data in air quality modeling.- Participants.- Authors Index.