Table 1.

Description of global ozone Free Air Concentration Enrichment (O₃‐FACE) facilities. Superscripts identify reference manuscripts that tested different target [O₃] within a given O₃‐FACE facility. Bold font indicates C₄ species tested in O₃‐FACE facilities.

Facility name	Location	Operational	Ecosystem	Plant species	Target ozone concentration	References
China FACE	Jiangdu, Jiangsu, China	2007–2012	Crop	Sativa oryza Triticum aestivum	1.5× ambient [O3]	Tang et al., 2011
China O3‐FACE	Yanqing, Beijing, China	2018–present	Forest	Populus deltoides Populus euramericana	1.5× ambient [O3]	Xu et al., 2021
KROFEX	Freising, Germany	2000–2007	Forest	Fagus sylvatica Picea abies	2× ambient [O3]	Werner and Fabian, 2002
FAOCE	New Delhi, India	2016–present	Crop	Cicer arietinum Triticum aestivum Zea mays	60–70 ppb	Yadav et al., 2019
India O3‐FACE	Lucknow, Uttar Pradesh, India	2018–present	Forest	Leucaena leucocephala	+20 ppb above ambient [O3]	Singh et al., 2021
FO3X	Florence, Italy	2015–present	Crop/forest	Passiflora edulis Phaseolus vulgaris Phoenix dactylifera Populus spp. Punica granatum Quercus spp. Saccharum spp.	1.2–1.4× ambient [O3]	Paoletti et al. 2017
Sapporo Forest	Sapporo, Hokkaido, Japan	2011–present	Forest	Betula platyphylla Fagus crenata Larix kaempferi Quercus mongolica Salix sachalinensis	60–70 ppba 2× ambient [O3]b	Watanabe et al., 2013 a Agathokleous et al., 2017 b
Tsukuba FACE	Tsukuba, Japan	2011–2019	Forest	Betula platyphylla	2× ambient [O3]	Kitao et al., 2021
Aspen FACE	Rhinelander, WI, USA	1998–2009	Forest	Acer saccharum Betula papyrifera Populus tremuloides	60–100 ppb	Dickson et al., 2000
SoyFACE	Savoy, IL, USA	2002–present	Crop	Glycine max Panicum virgatum Sorghum bicolor Zea mays	1.2–2× ambient [O3]a, b 60‐200 ppbc	Morgan et al. 2004 a Gillespie et al., 2012 b Betzelberger et al., 2012c