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

To artificially simulate the impacts of ground-level ozone (O-3) on vegetation, ozone FACE (Free Air Controlled Exposure) systems are increasingly recommended. We describe here a new-generation, three-dimensional ozone FACE, with O-3 diffusion through laser-generatedmicro-holes, pre-mixing of air and O-3, O-3 generator with integral oxygen generator, continuous (day/night) exposure and full replication. Based on three O-3 levels and assumptions on the pre-industrial O-3 levels, we describe principles to calculate relative yield/biomass and estimate impacts even at lower-than-ambient O-3 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 O-3 impacts on vegetation all over the world. (C) 2016 Elsevier B.V. All rights reserved.