Since a cost-benefit analysis on the subject cannot be carried out because of informational difficulties, a cost-effectiveness approach for identifying the most rational cours of action seems to be the appropriate tool. Based on a careful consideration of the costs and potential emission reductions of various control measures, the "cost-effectiveness analysis" selects the most cost-effective combination from the many possibilities of environmental improvement methods aiming at the same target, e.g. the reduction of SO2- and NOx-emissions. From a methodological point of view this approach is relatively straigthforward and the rational behind it is maximizing emission reduction while minimizing related control costs
