The chemistry that occurs in our atmosphere has far reaching implications for the biosphere through oxidation capacities, ultra-voilet absorption and radiative effects. Catalytic stratospheric ozone destruction chemistry combines bromine and chlorine homogeneous and heterogeneous processes to produce the massive ozone losses that result in increased ultra-voilet radiation levels over Antarctica and New Zealand. Large bromine explosions occur in the Antarctic and Arctic boundary layer and have been linked to the biogeochemical cycling of mercury in the polar regions. The affect of aerosol upon cloud microphysical properties is one of the largest uncertainties in ascertaining the future anthropogenic induced climate change. I will discuss some remote sensing spectroscopic methods used and modelling required to retrieve the vertical trace gas profile information and microphysical cloud properties from ground-based instrumentation. I will also discuss how kinetic information can be derived from airborne in-situ ClO measurements made over sunset. The ClOOCl photolysis rate and ClO+ClO <-> ClOOCl equilibrium constant determined in laboratory studies are compared with atmospheric observations.