The purpose of the project is to gain a better understanding of the implications of the new WHO air quality guidelines (AQG) from 2021 in a Nordic setting. Among other things, to estimate how far Nordic countries currently are from complying with the new guidelines, and to provide a foundation for assessment of measures in the Nordic countries to achieve the new recommended WHO levels. This understanding will also serve to provide a Nordic perspective on the new proposed EU's air quality directive from 2022.