Reactions at atmospheric surfaces can dramatically affect atmospheric composition and the fate of atmospheric pollutants. The complexity and heterogeneity of many atmospherically-relevant surfaces, along with a lack of experimental methods suitable to characterizing volatile, “messy” surfaces, makes predicting the effects of atmospheric surface chemistry difficult. Research in the Kahan group combines measurements of reaction kinetics with micro-spectroscopic characterization of atmospheric surfaces and laboratory-prepared proxies. We have identified the spatial distribution and chemical speciation of common environmental solutes and pollutants at model ice and aerosol surfaces and have related these findings to observed chemical reactivity. This research may resolve a decade-long debate surrounding reaction mechanisms at ice surfaces, and has the potential to improve predictions from coupled chemistry-atmospheric models that include surface reactions.