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...