This book has arisen directly from a course on Air and Water Pollution Control delivered by the first named author at the Technical University of Berlin. Extractions of this course have been presented in Brazil, Turkey and India. It was at the Indian Institute of Technology of Madras where the first named author got in contact with Professor Varma, who turned out to be a suggestive, cooperative coauthor. This book is addressed primarily to chemical, environmental and mechanical engineers, engaged in the design and operation of equipment for air pollution control. But it will certainly be helpful to chemists and physicists confronted with the solution of environmental problems. Furthermore it is intended as a text book for engineering courses on environmental protection. The goal of the book is the presentation of knowledge on design and operation of equipment applicable to the abatement of harmful emissions into air. The technology of air pollution control is of relatively young age, but it has already achieved a high degree of performance, due to the research and develop ment work invested in the last decades in this field.