Nato Challenges of Modern Society – serie

The North Atlantic Treaty Organization (NATO) established the "Committee on the Challenges of Modern Society" (CCMS) at the November 1969 meeting of the North Atlantic Council. The CCMS was charged with developing meaningful environmen­ tal and social programs that complement other international pro­ grams, and with showing leadership, first, in solution of exist­ ing problems and, second, in development of long-range goals for environmental protection in the NATO sphere of influence and in other countries as well. A first Pilot Study on Air Pollution was initiated by the CCMS at its inaugural meeting in December 1969. The United States (Environmental Protection Agency) has been the pilot nation with the Federal Republic of Germany (Federal Minis­ try of the Interior) and Turkey (Scientific and Technical Rese­ arch Council) as co-pilot nations. The Pilot Study on Air Pollution was an action program de­ signed to demonstrate and encourage the utilization of existing knowledge for the development of air quality management programs. It entailed the demonstration of a systems approach to air quali­ ty management. Case studies have been carried out in Ankara, Turkey; Frankfurt, Federal Republic of Germany; St. Louis, U.S.; Oslo, Norway; and South Holland Region, The Netherlands (NATO/CCMS Report No. 6, Appendices A- E).

In 1969 the North Atlantic Treaty Organization (NATO) established the Committee on Challenges of Modern Society (CCMS). The subject of air pollution was from the start one of the priority problems under study within the framework of various pilot studies undertaken by this Committee. The organization of a yearly conference dealing with air pollution modeling and its application has become one of the main activities within the pilot study relating to air pollution. The international conference was organized for the first five years by the United States and for the second five years by the Federal Republic of Germany. Belgium, represented by the Prime Minister's Office for Science policy, became responsible in 1980 for organizing the third five years of the annual conference. This volume contains the papers presented at the 15th NATO/CCMS International Technical Meeting (ITM) on Air Pollution Modeling and Its Application, held in St. Louis, Missouri, from the 15th to 19th April 1985. This ITM was jointly organized by the Prime Minister's Office for Science Policy, Belgium (Pilot Country); by the Environmental Protection Agency, Atmospheric Sciences Research Laboratory, United States (Host Country); and by Washington University, Mechanical Engineering Department (Host Organization).

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.

This book is a summary of the presentations and discussions at the Workshop on Methods of Pesticide Exposure Assessment held in Ottawa, Canada, on October 5-8, 1993. The event was a joint effort of Health Canada and the North Atlantic Treaty Organisation and was officially supported by the United States Environmental Agency and the Organisation for Economic Co-operation and Development (OECD). The goal of the workshop was to examine current issues in the field of pesticide exposure assessment with the aim of reaching an internationally harmonized approach to methods of exposure assessment. With regulatory agencies of OECD Member countries moving towards the harmonization of data requirements, it was timely and beneficial to bring together international experts in the field of pesticide exposure assessment to discuss current issues. Approximately 60 delegates and 20 observers participated, including individuals from 15 different countries representing academia, government, industry and international organizations. A guidance document on methods of pesticide exposure assessment was presented as a means to achieving the goal of international for critique and discussion harmonization. After extensive discussion, the workshop delegates agreed in principle to procedures for revising the guidance document. Following revision and further review by a designated peer review group, the revised document will be submitted to the OECD for consideration as a draft OECD Guidance Document on pesticide exposure assessment methods. Both the revised and original documents are included in these proceedings.

In 1969 the North Atlantic Treaty Organization (NATO) cstablishcd thc Committee on Challenges of Modern Society (CCMS). The subject of air pollution was from the thc very beginning one of the priority problems umier deliberation within the tJ-amcwork of various pi- lot studies undertaken by this committee. The organization of a yearly conference dealing with air pollution modelling and its application has become one of the main activities within thc pilot study rclating to air pollution. Pleasc see the listing on the next page for completed NATO/CCMS Pilot Studies and the International Technical Meetings (ITM) on Air Pollution Modelling and Its Application. This volume contains the papers at the 22ND lTM, being held in Clermont-Ferrand, France during June 2 -6,1997. It was attended by 152 participants representing 33 countries. This lTM wasjointly organized by the Ris0 National Laboratory of Denmark (pilot country): the Laboratoire Associe de Meteorologic Physique, associated with the Centre National de la Recherche Scientifique, the Universite Blaise Pascal. and the Observatoire de Physique du Globe de Clermont-Ferrand, France (host country).We wish to express our gratitude to the sponsors that made this conference possible. In addition to tinancial support from NATO/CCMS, the conference received contributions from Centre National de Recherche Scientitique, Observatoire de Physique du Globe de Clermont-Ferrand, Universite Blaise Pascal, Electricite de France, lnstitut Francais du Pe- trole, Conscil Regional d'Auvergne, Conseil General du Puy de DC1I11e, Mairie de Clermont- Ferrand, SATCAR Semaine des arts techniques et culture de l'automobile et de la route.

This text includes a comprehensive updated analysis of cancer risk assessment procedures, with particular attention to biologically-based modelling. The presented arguments include the basic assumptions of cancer risk assessment methods, their biological basis and theoretical background, the relevant data sources, the multistage models (including the two-stage and clonal expansion models and pharmacokinetic models), and the relevant biomarkers, together with fundamental statistical considerations and selected case studies and examples of practical applications. The uncertainty of assessment and the practical use of the proposed methods are suggested. The book examines in detail the updated biologically-based carcinogenic risk assessment procedures together with the usually employed procedures, as well as background information on which they are based. It also proposes new ideas and methods in this field. Furthermore, it includes criteria and methods for practical application and use of the examined procedures.

The study of Health and Medical Aspects of Disaster Preparedness was approved by NATO/CCMS in 1985 with the first pilot study meeting in June of that year. The pilot study, under the leadership of the United States and Belgium, focused on the current status of disaster preparedness in partici­ pating nations. An objective look was taken at the availability or resources to cope with disasters from an international standpoint. The types of disaster settings that were reviewed in the study included the following: (1) Earthquakes, floods, hurricanes, avalanches (2) Nuclear power plant accidents or spills (3) Water and aircraft accidents (4) Building fires, building collapses (5) Contamination by hazardous chemicals or biological waste (6) Civil disturbances A disaster can strike anywhere at any time. Some nations and local communities have well-developed disaster plans with which to meet catastrophic situations. The fact is that most communities are without written and coordinated disaster plans which offer their citizens the most effective and comprehensive protection in these unexpected and often critical situations. Disaster has been defined as a sudden event which involves large numbers of people and results in loss of life, serious injury and property loss. together with a severe disruption of community organization and services. In the United States, thousands of people are killed and injured in disasters every year. Thus, disasters constitute a serious problem in both individual and public health terms in this country alone. Disasters can be classified as natural and man-made.

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 priority 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, became responsible in 1980 for the organization of this symposium. This volume contains the papers presented at the 14th Inter­ national Technical Meeting on Air Pollution Modeling and its Appli­ cation held in Copenhagen, Denmark, from 27th to 30th September 1983. This meeting was jointly organized by the Prime Minister's Office for Science Policy, Belgium, and the National Agency of Environmental Protection, Air Pollution Laboratory, Ris~ National Laboratory, Denmark. The conference was attended by 103 partici­ pants and 43 papers have been presented. The members of the se­ lection committee of the 14th I.T.M. were A. Berger (Chairman, Belgium), W. Klug (Federal Republic of Germany), K. Demerjian (United States of America), L. Santomauro (Italy), R. Van Dop (The Netherlands), R.E. Turner (Canada), C. De Wispelaere (Coordinator, Belgium).

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.

This volume represents the findings of the six-year NATO CCMS pilot study on the use of remote sensing for the control of marine pollution, a joint study conducted by countries confronted by the problems that arise from the prevention of, and the fight against, deliberate and accidental oil spills. In 1976, when I submitted to the Committee on the Challenges of Modern Society the draft of this pilot study, the use of remote sensing in the area covered by the project was still at the experimental research stage. Two years later, the Amoco Cadiz disaster occurring on the Brittany Coast gave ~he opportunity to demonstrate the important role that remote sensing could play in the fight against major oil spills. At the same time, many countries engaged in the fight against the deliberate discharge of oil from ships became aware of the po­ tential of remote sensing to help combat this type of illegal activity. Compiling this volume has afforded me the opportunity to re-read the papers that were presented at the workshops in Washington, D.C. and Paris, which were held April 1979 and October 1982, respectively. Not only is the material still of current interest, but also some recommendations expressed by the experts have already received international recognition. This applies, in particular, to the Isowake experiments, which were originated by the United States (U.S. Coast Guard) and the United Kingdom (Warren Spring Laboratory).

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.

Putting together these Proceedings has afforded me the oppor­ tunity to re-read the papers which were presented last October here in Washington. In retrospect, the 1981 NATO/CCMS Symposium on Hazardous Waste Disposal maintains the impression of excellence expressed by the par­ ticipants at the actual event. The scope of the subject-matter and quality of its presentation indicate that we did attain the Sympos­ iums's objective--a comprehensive review of the international status of hazardous waste disposal. It is my hope that in your own evaluation of these proceedings, you will share my conviction that the Symposium--conceived three years ago, approved by the NATO/CCMS Pilot Study experts in Oslo in October 1980, and taking place a year later--was indeed worthwhile and that this record of its proceedings will be useful for many years to come. John P. Lehman Washington, D.C. Editor June 1982 v CONTENTS OPENING REMARKS • • • • • • • • • 1 Dr. John W. Hernandez, Jr.

The 20th International Technical Meeting on Air Pollution Modelling and Its Application was held in Valencia, Spain, during late 1993. At this conference, a new record of abstracts was submitted, a new record of scientists participated, and a new record of countries was represented. This clearly indicates society's continuous and growing interest in, as well as importance of, the complexities associated with the modelling of air pollution. The conference addressed the following main subjects: integrated regional modelling, global and long-range transport, new modelling developments, accidental releases, and model assess­ ment and verification. In addition, two project-oriented workshops were organized as part of the conference. The many contributing authors and scientists taking active part in the discussions following the papers, have made this proceeding a record of the current status in the field of air pollu­ tion modelling. We want to express our gratitude to their efforts. We also wish to extend our gratitude to the sponsors that made this conference possible. In addition to financial support from NATOjCCMS the conference received contributions from CEAM, the European Asso­ ciation for the Science of Air Pollution, Danish Center for Air Research, and Ris0 National Laboratory. A special grant was given by NATOjCCMS to facilitate attendance of scientists from Central and Eastern Europe. We also wish to express our gratitude to Rosa Salvador and Pilar Zamora of CEAM, who laboriously organized the conference pre-proceedings, and to Anne N0rregaard and Ulla Riis Christiansen of Ris0 National Laboratory, who seved as conference secretariat.

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.

Erich W. Bretthauer, Chairman of the Exposure and Hazard Assessment Working Group U. s. Environmental Protection Agency Washington, D. C. The efforts of the Exposure and Hazard Assessment Working Group were focused on the exchange of information on a variety of topics including research projects, regulations/statutes, analytical laboratories, and methods of exposure/risk assessment involving CDDs and CDFs. It was evident to the leaders of the Working Group that several of the knowledge voids had to be addressed on a fundamental level before expanded efforts could be made. Several questions needed to be answered: • Who has done research on this topic, and what do the data indicate? • Who is performing research now, and what are their capabilities? • How are other nations addressing this problem, and do they have legislative mandates in place? • Is there a general consensus on the topic? The members of the Working Group believed that these questions could be answered by surveying the major participants in the field of interest. Three principal survey efforts were performed by the Working Group, which collected information on research, regulations/statutes, and analytical laboratories from each of the participating nations. In addition to answering these fundamental questions, these efforts also fulfilled the major objectives of the entire Pilot Study. The collection, analysis, and distribution of information on research projects, regulations/statutes, and analytical laboratories were very useful efforts in helping to fill some of the basic knowledge voids.

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 first meeting of the NATO/CCMS Pilot Study "Dose-Response Analysis and Biologically-Based Risk assessment for Initiator and Promoter Carcinogens" was held in Rome, Italy, in the spring of 1991, and was followed by annual or bi-annual meetings held in Germany, Greece, Netherlands, Portugal, USA, up to the end of 1995; in large part supported by NATO/CCMS grants or fellowships, and organized by Pilot Study participants. The Pilot Study activity has been characterized by a higly collaborative atmosphere, which was essential for a deep and detailed analysis of a problem on which different points of view, methodological approaches and regulations exist in the various member countries. The Pilot Study was aimed at proposing a carcinogenic risk assessment procedure which is based on a detailed analysis of the relevant biological processes, and may also consent the verification of hypotheses. The specific form of theoretical and mathe­ matical models is identified by considering and using the whole set of objective data available. The multidisciplinary approach of the pilot study is reflected by the struc­ ture of this book. Each chapter is the result of the cooperation of several authors from to produce a comprehensive manual that includes different countries; its objective was both theoretical and practical information.

In 1969 the North Atlantic Treaty Organization (NATO) established the Committee on Chal- lenges of Modern Society (CCMS). The subject of air pollution was from t,lw start one of the priority problems under study within the framework of various pilot. studi('s undertaken by this committee. The organization of a periodic conference dealing with air pollution modelling and its application has become one of the main activities within the pilot ~tudy relatillg to air pollution. The first five international conferences were organized by the United Statcs as the pilot country; the second five by the Federal Republic of Germany: thc third five by sselgium; the next four by The Netherlands; ami the two most recent by Delllllark. This volume contains the papers presented at the 21st NATOjCCMS International Technical Meeting (ITM) on Air Pollution Modelling and Its Application, held in ssaltimorc. Maryland, during November 6-10, 1995. This ITM was jointly organized by the Riso National Laboratory of Denmark (Pilot Country); by the EPA National Exposurp Research Labora- tory, United States (Host Country); and by thc American MNeorologiea.! Soci('t.: *. Cnited States (Host Organization).The ITM was attended by 137 participants representing 29 countri('~ from North and South America, Europe, Asia and Australia. The members of t.hc NATO/CCMS Scientific Committee for the 21st ITM were R.M. van Aalst (The Nethcrlallds), D. Allfossi (Haly), C. Borrego (Portugal), N. Chaumerliac (Francc), H. van Dop (Thc :\Tethcrla.nds). S.-E. Gryning.

The pilot study on estuarine management was initiated by the NATO Committee on the Challenges of Modem Society (CCMS). The objective of this project was to make a comparison of several estuarine management strategies and to formulate a set of recommen­ dations and planning guidelines to restore polluted estuaries, to prevent further estuarine deterioration, and to manage conflicting demands stemming from human activities. The first results of this NATO-CCMS project were reported in 1982, describing six estuaries and their management approaches. In 1985 CCMS decided a subsequent research project should be performed to achieve the original objectives. This second research project was basically done by way of a comprehensive questionnaire that was sent to authorities of estuarine areas all over the world. Eleven questionnaires have been received. In some instances, the questionnaires were not fully completed for several reasons. Especially, data on water quality was lacking. As a result, less attention will be paid to related aspects as originally intended. This study shows that knowledge of the number of functions and conflicts of estuaries may provide relevant information concerning the severity of the problems as well as the propensity towards planning of water systems.

Air pollution remains a major environmental issue despite many years of study and much legislative control. In rec~nt times, pollution on a global scale has become of particular concern. The gradually changing con­ centration of trace gases in the global troposphere due to man's activity is becomming a matter of serious concern. No scientist would dare to pre­ dict in detail the consequences of this gradual change due to its immense complexity involving social and economic factors and near countless chemical and phjsical cycles in our biosphere. In this chain of processes, the transport of pollution is an important factor, but only a factor. Therefore, I would like to emphasize that the mOdelling of atmospheric transport is becoming more and more an activity which fits into larger frameworks and can no longer be exercised as a single step, which bridges the gap between emissions and policy measures. This is also reflected in the topics and papers which were presented at this conference. The topics were: - emission invetories for and source treatment in air pollution dispersion models; - modelling of accidental releases; - regional and global scale dispersion mOdelling; including boundary layer-free troposphere exchange processes and subgrid scale parameter­ isations; - model verification and policy implications; - new developments in dispersion modelling and theory. 56 papers were presented in these sections. While many posters were dis­ cussed in a special session.

The North Atlantic Treaty Organization (NATO) established the "Committee on the Challenges of Modern Society" (CCMS) at the November 1969 meeting of the North Atlantic Council. The CCMS was charged with developing meaningful environmen­ tal and social programs that complement other international pro­ grams, and with showing leadership, first, in solution of exist­ ing problems and, second, in development of long-range goals for environmental protection in the NATO sphere of influence and in other countries as well. A first Pilot Study on Air Pollution was initiated by the CCMS at its inaugural meeting in December 1969. It resulted in documents about the definition of criteria for the effects of air pollutants as well as the development of assess­ ment methods for air quality in urban areas. A second Air Pollution Pilot Study (1975-1979) worked out the basics for setting up assessment methods for emissions inven­ tories, techniques for the practical application of meteorologi­ cal diffusion models as well as the development of guidelines for an Air Quality Management System (AQMS). Within this second Air Pollution Pilot Study attention to modelling concentrated on the Gaussian Plume Model. A third Pilot Study on Air Pollution Control Strategies and Impact Modelling then was initiated in 1979 and started in 1980.

The Council of the North Atlantic Treaty Organization (NATO) established the "Committee on the Challenges of Modern Society" (CCMS) in 1969. The CCMS was charged with developing meaningful environmental and social programmes for solving existing problems and developing long-range goals for environmental protection. In 1983, at the Fall Plenary of the CCMS, the Norwegian delegate Dr. H.C. Christensen, proposed a Pilot Study on "Risk Management of Chemicals in the Environment". A draft proposal, written by Dr. Kari Kveseth of the Center for Industrial Research in Oslo, was presented. Dr. Christensen also informed the participants at the meeting that Norway was willing to act as the Pilot Country. The project was initially planned for 3 years, but it was later extended through 1987. The inaugural meeting was held in Oslo in April 1984 with participants from Denmark, Greece, France and Italy, in addition to representatives from several Norwegian institutions. The attendees concluded that a Pilot Study, as delineated in the draft proposal, would be useful, and it was decided to work out a detailed project plan based on the proposal.

In 1969 the North Atlantic Treaty Organization established the Committee on the Challenges of Hodern Society. Air Pollution was from the start one of the priority 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, repre­ sented 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 12th Interna­ tional Technical Meeting on Air Pollution Modeling and its Appli­ cation held at SRI International, Menlo Park, California in the USA from 25th to 28th August 1981. The meeting was jointly organized by the Prime Minister's Office for Science Policy Programming, Belgium and SRI International, USA. The conference was attended by 109 participants and 51 papers have been presented. The members of the selection committee of the 12th I.T.M. were A. Berger (Chair­ man, Belgium), W. Klug (Federal Republic of Germany), L.E. Niemeyer (United States of America), L. Santomauro (Italy), J. Tikvart (United States of America), M.L. Williams (United Kingdom), H. Van Dop (The Netherlands), C. De Wispelaere (Coordinator, Belgium).

In 1969 the North Atlantic Treaty Organization (NATO) established the Committee on Challenges of Modern Society (CCMS). The subject of air pollution was from the start one of the priority problems under study within the framework of various pilot studies undertaken by this Committee. The organization of a yearly conference dealing with air pollution modeling and its application has become one of the main activities within the pilot study relating to air pollution. The international conference was organized for the first five years by the United States and for the second five years by the Federal Republic of Germany. Belgium, represented by the Prime Minister's Office for Science policy, became responsible in 1980 for organizing the third five years of the annual conference. This volume contains the papers presented at the 15th NATO/CCMS International Technical Meeting (ITM) on Air Pollution Modeling and Its Application, held in St. Louis, Missouri, from the 15th to 19th April 1985. This ITM was jointly organized by the Prime Minister's Office for Science Policy, Belgium (Pilot Country); by the Environmental Protection Agency, Atmospheric Sciences Research Laboratory, United States (Host Country); and by Washington University, Mechanical Engineering Department (Host Organization).