Impacts of climate change on air pollution levels in the northern hemisphere with special focus on Europe and the Arctic

The evolution in air pollution levels and spatial distribution in the 21 st century is investigated with respect to climate change. The coupled atmosphere-ocean general circulation model ECHAM4-OPYC3 is providing, meteorological fields for two time slices (1990s and 2090s) to the chemical long-range transport model DEHM-REGINA. The dominating impacts from climate change on a large number of the chemical species are related to the predicted temperature increase since most of the reaction rates of the involved species are temperature dependent. The ECHAM4-OPYC3 projects a global mean temperature increase of 3 K with local maxima up to I I K in the Arctic. As a consequence of this temperature increase, the temperature dependent biogenic emission of isoprene is predicted to increase significantly over land by the DEHM-REGINA model simulation. This leads to an increase in the ozone production and together with an increase in water vapour to an increase in the number of free OH radicals. Furthermore an increase in the number of radicals contributes to a significant change in the typical life times of many species, since hydroxyl radicals are participating in a large number of chemical reactions.