Air pollution, a major concern at the end of the 20th century, still remains a significant problem to be solved today. Traditionally, industrial waste gases have primarily been treated through physical or chemical methods. The search for new, efficient, and cost-effective alternative technologies has led to the development and, more recently, the improvement of gas phase bioreactors. This book is the first single text to provide a complete, comprehensive picture of all major biological reactors suitable for solving air pollution problems. The text describes the main features and covers the major aspects, from microbiological to engineering, as well as economic aspects, of the different types of bioreactors. The book also presents an in-depth review of the subject, from fundamental bench-scale research to industrial field applications related to the operation of full-scale systems successfully treating polluted air in Europe and the United States. Material dedicated to more conventional non-biological technologies has also been included, to provide a complete overview of the different alternative treatment processes. Audience: The different chapters have been written by international experts, as a result of a fruitful collaboration between European and American scientists and engineers. The resulting text is a high quality, valuable reference tool for a variety of readers, including graduate and postgraduate students, researchers, professors, engineers, and those professionals who are interested in environmental engineering and, more specifically, in innovative air pollution control technologies.