The completion of the Pilot Study on Air Pollution Assessment methodology and Modeling this year coincides with the tenth anniversary of the Committee on the Challanges of Modern Society of the North Atlantic Treaty Organization. Therefore, it is the right time to make balance and to publish an intermediate report on the common effort of experts of the NATO countries concerning the field of air pollution. The knowledge and experience actually available in the NATO countries was collected and published by the active members of the pilot study in twenty technical documents on emissions inventories, immissions forecasts, effects of air pollutants and the state of the art concerning the reduction of emissions as well as in ten scientifical publications on the development of mathematical meterorological dispersion models.