Ice surfaces play a commanding role in atmospheric and interstellar chemistry.  For example, it is well known that the snowpack and polar stratospheric cloud particles participate in the formation of ozone consuming compounds in the Earth’s atmosphere.  Combinations of molecular beam and spectroscopic techniques can help quantify the complex coupled kinetics for the adsorption, desorption, diffusion and uptake of pollutants by ice as well as those for phase separation and crystallization in the bulk.  Quantitative data is required for proper interpretations of heterogeneous atmospheric chemistry, climate proxies from ice cores, etc.  We will present our most recent results on the study of elementary processes that yielded detailed molecular-level insight into the rich and complex behaviour of ice surfaces and recent progress towards more complex and atmospherically relevant systems.