In preparation for the upcoming revision the German Environment Agency (UBA) from a scientific point of view has assessed the possibility to meet the proposed WHO Guidelines Levels, the applicability of improved chemical transport models and advanced monitoring methods for air quality assessment as well as concepts for a better protection of ecosystems from air pollutants. In the following we propose criteria for binding and non-binding air quality standards as well as a monitoring strategy beyond compliance checking. The considerations are based on the German situation but may be extrapolated to many other European Member States.