A new-generation 3D ozone FACE (Free Air Controlled Exposure).

To artificially simulate the impacts of ground-level ozone (O3) on vegetation, ozone FACE (Free Air Controlled Exposure) systems are increasingly recommended. We describe here a new-generation, three-dimensional ozone FACE, with O3 diffusion through laser-generated micro-holes, pre-mixing of air and O3, O3 generator with integral oxygen generator, continuous (day/night) exposure and full replication. Based on three O3 levels and assumptions on the pre-industrial O3 levels, we describe principles to calculate relative yield/biomass and estimate impacts even at lower-than-ambient O3 levels. The case study is called FO3X, and is at present the only ozone FACE in Mediterranean climate and one of the very few ozone FACEs investigating more than one stressor at a time. The results presented here will give further impulse to the research on O3 impacts on vegetation all over the world.