The UNECE Convention on Access to Information, Public Participation in Decision-Making and Access to Justice in EnvironmentalMatters (Aarhus Convention) has been concluded by the EU and its member states as a “mixed agreement”. In their interrelation the perspectives of both public international and European Union law help to draw a clearer picture of the scope of the duty incumbent on the EU to implement the Convention’s stipulations. It is argued that from the internatio