Book excerpt: This is the new, fourth edition of the book on dispersion modeling of continuous, buoyant air pollution plumes which takes nothing for granted. Every equation is completely derived step-by-step without any complicated or advanced mathematics. Every constraint and assumption is fully explained. A set of self-study exercises is also included with the book.The subjects covered in the book include atmospheric turbulence and stability classes, buoyant plume rise, Gaussian dispersion calculations and modeling, time-averaged concentrations, wind velocity profiles, fumigations, trapped plumes, flare stack plumes and much more ... with a great many example calculations. Copies of the book have been purchased in the U.S.A., Canada, Mexico, South America, Europe, Australia, Africa and Asia (in a total of 57 countries), and are available in over 130 libraries worldwide. The book has been very widely referenced and cited in the technical literature and on the Internet.