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.