The chemically active climate gases ozone (O3) and methane (CH4) respond to variability in the
current climate and will be affected by future climate change ([1,2]). O3 and CH4 will in addition to
being influenced by atmospheric chemistry respond on changes in solar radiation, atmospheric
temperature and dynamics, and are expected to play an important role for processes determining the
interaction between the biosphere and the atmosphere ([2–4]). CH4 chemistry is also affecting climate
through its impact on ozone ([5]). Emissions of air pollutants and their precursors, which determine
regional air quality by perturbing ozone and methane has also the possibility to alter climate. Climate
changes will affect chemical processes in the atmosphere through transport on local and large scales
and through removal and formation of pollutants ([6,7]).