The development of the CSIRO Lagrangian Atmospheric Dispersion Model, LADM, represents a major advance in assessing air pollution impacts. LADM is a synthesis of practical implementations of current scientific knowledge of boundary-layer meteorology, dynamical meteorology in complex geographical regions, plume dynamics, turbulent dispersion in thermally unstable and stable conditions and photochemical smog kinetics. The most startling result from the application of LADM in coastal regions in several studies is the prevalence of recirculations of pollutants back over the emission region later in the day or even during the following day, perhaps then as smog. These and other results are illustrates by recent Australian studies. Most recently, LADM has been extended to permit prediction of dry deposition. Now, dry deposition estimates for complex conditions are possible.