Polar firn and ice, particularly from Antarctica, represents more or less frozen ultra-pure water. Nevertheless, the tiny signals of trace impurities in polar ices, which are typically in the parts per billion down to parts per trillion range, provide information about climate and composition of the atmosphere in the past. The source for impurities in firn and ice layers are aerosols and water soluble trace gases deposited on the ice surface. Thus, the chemical parameters stored in solid precipitation and accumulated on polar ice sheets provide a unique key to assess the composition and natural variability of the paleo-atmosphere. 
Specifically, from ice cores information about local temperature, precipitation rate, wind strength, aerosol fluxes of marine, volcanic, terrestrial, cosmogenic, and last not least, anthropogenic origin can be derived. In the following table the most important chemical trace compounds found in polar ices, their bio-geochemical sources and connection to parameters determining the climate are listed:

However, it is not simple to decipher the aerosol records in ice cores with respect to past climate and atmospheric composition. There is a basic need to understand the present bio-geochemical cycling of nitrogen and sulfur in polar regions, the tropospheric chemistry above polar ice shields and the physico-chemical processes governing air to snow transfer of atmospheric trace compounds. Thus, apart from investigating the chemical composition of ice cores, another crucial point of our activities is to investigate the tropospheric chemistry in polar regions, especially in Antarctica. This is realized by the measuring program of the  air chemistry observatory at Neumayer . Basically our research activities within this topic can be resumed in the following projects:

Carbon cycle modelling
Gases in ice cores
Dust in ice cores.