In 1969 the North Atlantic Treaty Organization established the Committee on the Challenges of Modern Society. Air Pollution was from the start one of the pri9rity problems under study within the framework of the pilot studies undertaken by this Committee. The organization of a yearly symposium dealing with air pollution modeling and its application is one of the main activities within the pilot study in relation to air pollution. After being organized for five years by the United States and for five years by the Federal Republic of Germany, Belgium, represented by the Prime Minister's Office for Science Policy Programming, became responsible in 1980 for the organization of this symposium. This volume contains the papers presented at the 13th Inter national Technical Meeting on Air Pollution Modeling and its Appli cation held at lIe des Embiez, France, from 14th to 17th September 1982. This meeting was jointly organized by the Prime Minister's Office for Science Policy Programming, Belgium, and the Ministere de l'Environnement, France. The conference was attended by 120 participants and 45 papers have been presented. The closing ses sion of the 13th I. T. M. has been attended by Mr. Alain Bombard, French Minister of the Environment. The members of the selection committee of the 13th I. T. M. were A. Berger (Chairman, Belgium), W. K1ug (Federal Republic of Germany), K. Demerjian (United States of America), L. Santomauro (Italy), M. L. Williams (United Kingdom), H. Van Dop (The Netherlands), H. E. Turner (Canada), C.

Zusammenfassung
After being organized for five years by the United States and for five years by the Federal Republic of Germany, Belgium, represented by the Prime Minister's Office for Science Policy Programming, became responsible in 1980 for the organization of this symposium.

Inhalt
Lagrangian Modeling.- Aspects of Lagrangian Air Pollution Modeling.- The Integral Equation of Diffusion.- Lagrangian Long Range Air Pollution Model for Eastern North America.- Some Comparisons Between Lagrangian and Simple Source-Oriented Models for Long Range Atmospheric Transport and Dispersal of Radioactive Releases.- Application of Personal Computers to Lagrangian Modeling in Complex Terrain.- On Dispersion in the Convective Boundary Layer.- A New Monte-Carlo Scheme for Simulating Lagrangian Particle Diffusion with Wind Shear Effects.- Preliminary Tests of the Introduction of Lagrangian Dispersion modeling in a 3-D Atmospheric Meso-scale Numerical Model.- Studies of Plume Transport and Dispersion Over Distances of Travel Up to Several Hundred Kilometers.- Lagrangian Modeling of Dispersion in the Planetary Boundary Layer of Particulate Released by a Line Source.- A Monte-Carlo Model for the Simulation of Long-Range Transport of Air Pollutants.- Preliminary Analysis of Lagrangian Monte-Carlo Methods for Nonhomogeneous Turbulence.- PPI-Theory for Particle Dispersion.- Modeling Cooling Tower and Power Plant Plumes.- An Improved Analytical Model for Vapour Plume Visible Outline Predictions.- Simulation of Atmospheric Effects of Industrial Heat Releases: The Artificial Convection Program.- The Cooling Tower Model Smoka and Its Application to a Large Set of Data.- Dynamic Interaction of Cooling Tower and Stack Plumes.- Numerical Modeling of Cooling Tower Plumes: Comparison with Experiments.- Modeling the Dispersion of Heavy Gases.- The Modeling of Dispersion of Heavy Gases.- Numerical Simulations of Atmospheric Releases of Heavy Gases Over Variable Terrain.- Diffusion of Heavy Gases.- Entrainment Through the Top of a Heavy Gas Cloud, Numerical Treatment.- Maplin Sands Experiments 1980: Dispersion Results from Continuous Releases of Refrigerated Liquid Propane and LNG.- Remote Sensing as a Tool for Air Pollution Modeling.- Correlation Spectrometry as a Tool for Mesoscale Air Pollution Modeling.- Doppler Acoustic Sounding: Application to Dispersion Modeling.- Plume Modeling from Meterological Doppler Radar Data.- Observations and Predictions of Inversion Penetration by a Buoyant Industrial Plume.- Acoustic Sounder Data as Meteorological Input in Dispersion Estimates.- Simulation of Sulphur Dioxide Mass-Flow Over Milan Area.- Tetroon Flights as a Tool in Atmospheric Meso-Scale Transport Investigation.- Dispersion Modeling Including Photochemistry.- Progress in Photochemical Air Quality Simulation Modeling.- Evaluation of the Performance of a Photochemical Dispersion Model in Practical Applications.- A Second Generation Combined Transport/Chemistry Model for the Regional Transport of SOx and NOx Compounds.- Acid Deposition of Photochemical Oxidation Products A Study Using a Lagrangian Trajectory Model.- Simulation of a Photochemical Smog Episode in the Rhine-Ruhr Area with a Three Dimensional Grid Model.- Oxidant Formation Described in a Three Level Grid.- Evaluation of Model Performances in Practical Applications.- Site-to-Site Variation in Performance of Dispersion Parameter Estimation Schemes.- Estimates of Vertical Diffusion From Sources Near the Ground in Strongly Unstable Conditions.- Validation of a Single Source Simulation by Means of Past and Actual Air Quality Measurements.- Application of a Three-Dimensional Model to the Calculation of Trajectories: A Case Study.- Estimation of Uncertainties in Transfer Matrix Elements in Long Range Transport Modeling.- Evaluation of a K-Model Formulated in Terms of Monin-Obukhov Similarity with the Results from the Prairie Grass Experiments.- Atmospheric Diffusion Modeling and Optimal Air Quality Control Strategies.- The Applications of an Integral Plume Rise Model.- Estimation of Diffuse Hydrocarbon Leakages from Petrochemical Factories.- Participants.- Author's Index.