Review and Adjustment Under the UN-ECE Transboundary Air Pollution Treaty Regimes and the Implementing EU Legislation

This article explores to which extent the mechanisms to review and adjust the emission reduction commitments, contained in some selected UN-ECE transboundary air pollution treaty regimes, as well as in the implementing EU legislation, facilitate the efforts of Parties in meeting their non-modifiable targets, in particular, when new circumstances arise that would require the legal regime ``to adapt''. In terms of review procedures, the article shows that the activity of the expert review teams, of the Implementation Committee and of the EU Commission (i.e., the monitoring bodies) contribute to make sure that the emission data in the inventories are correct and comparable (not underestimated or overestimated) in relation to the final targets. In terms of adjustments, among the instruments analysed, the revised Gothenburg Protocol proves to be very responsive to new circumstances and the new NEC Directive goes even further. Finally, the illustrative example of the Protocol on Heavy Metals shows that the uncertainties inherent in setting emission reduction commitments can also have an impact on the reporting obligations. In this context, the implementing EU legislation (mainly the Ambient Air Quality Directive) proves to be responsive to new circumstances at a lesser level compared to new NEC Directive. Overall, these procedures mitigate the “rigidity” of the treaty regime and help Parties to achieve their final targets.