An emission inventory for all of Europe shows that between 1980 and 1985 NOx emissions almost stabilized as a consequence of structural changes in the energy consumption. This paper analyzes potential future emissions of nitrogen oxides for the hypothetical case of no control measures being applied and the effects of the reduction commitments made in the ‘Sofia Protocol’ and the ‘Declaration on a 30% cut’ of NOx emissions in Europe. Finally, the costs for implementing the committed emission reductions are assessed.