This book is written as a text and reference for motivated seniors and first- or second-year graduate students in the area of chemical transport in the environment. The students in environmental sciences and engineering programs generally come from various backgrounds, such as chemical, civil, and mechanical engineering; chemistry; physics; biology; and environmental science. Courses are needed that focus on fundamentals of the environmental field, in this case environmental transport.

Emphasis is placed on developing the perspective and tools that will help students through graduate school and beyond. The diffusion equation is prevalent throughout environmental science and engineering, formulated to determine diffusion, turbulent diffusion, and dispersion of chemicals, in addition to convection. Learning about tools to solve this equation for different applications or boundary conditions is a task best undertaken early in one's career.

Without an environmental application, the material in this text may be perceived as dry and tedious. For that reason, much of the development of solution techniques is contained in examples of applications to environmental transport. Chapter 2, titled “The Diffusion Equation,” is essential to the remainder of the text, which uses the examples provided in Chapter 2 to further develop solutions for other applications.

There are three reasons to develop analytical solutions to the diffusion equation during this age of numerical solutions. First, numerical solutions do not provide a good physical understanding of how diffusion works and what diffusion is.