The various articles which make up this book concern both modelling (numerical and analytical) and experimental activities in relation to aspects of environmental fluid dynamics. Issues dealt with include the dispersion of pollutants in both urban and extra-urban areas, the effect of obstacles on the flow and dispersion in the turbulent boundary layer, and the simulation of the planetary boundary layer in proximity with the earth's surface. There is also a discussion of advanced issues which are also of interest in the sphere of urban planning, such as "wind comfort" and the effects of the shelter belt.