On 28 - 31 August 2017, the meeting of the ICP Forests Expert Panel on Ambient Air Quality and the Intercalibration Course on ozone induced symptoms took place in Trento, Italy. The event was organized by the Research and Innovation Centre of Fondazione Edmund Mach FEM in collaboration with The Swiss Federal Institute for Forest, Snow and Landscape Research WSL welcoming 12 partners from 6 ICP Forests member states as well as external scientists. Introducing lectures on air quality in Trentino, ozone-induced visible symptoms and the harmonized assessment methods in the field were accompanied by a photo-exercise and a one-day field trip. Within the mountainous area of Trentino features, pronounced ozone-induced visible symptoms were detected on several woody species such as Fagus sylvatica, Cornus sanguinea; Corylus avellana and Viburnum lantana making it a perfect location for an Intercalibration Course. To complete the picture on ozone injury, in-field validation of ozone symptoms using smart-phone based microscopy techniques were presented.