This volume covers topics on atmospheric transport and diffusion processes, with particular emphasis on the Atmospheric Boundary Layer (ABL). The ABL is the region in which the atmosphere experiences surface effects through vertical exchanges of momentum, heat and moisture. This is the part of the atmosphere in which most air pollution is released and transported by mean winds and dispersed by turbulent eddy motion. Contributors were chosen for their expertise on one or more aspects of the ABL. The subject material will be of interest to researchers, as well as to students intending to take up studies in the field of atmospheric Boundary Layer and Air Pollution Meteorology. The third chapter will be of interest to planners, administrators and scientists working in regulatory agencies.