Ozone pollution and carbon assimilation in vegetation: mechanisms, interactions, and global implications

Ozone (O₃) and carbon dioxide (CO₂) critically influence climate change through complex interactions with terrestrial vegetation. Ground-level O₃ forms via NO_x and VOCs photochemistry, while CO₂ primarily comes from fossil fuel combustion. Their atmospheric concentrations interact through physicochemical processes: elevated CO₂ levels may accelerate photochemical reaction rates of O₃ precursors due to climate warming, while O₃, as a potent oxidant, alters atmospheric oxidation capacity and consequently affects the lifetime of other greenhouse gases. Plant stomata serve as the primary interface for gas exchange between terrestrial ecosystems and the atmosphere, playing a critical role in regulating O₃ uptake and CO₂ assimilation. Plants simultaneously uptake CO₂ for photosynthesis and absorb O₃ through stomata. Interestingly, rising CO₂ concentrations induce partial stomatal closure, thereby reducing O₃ uptake. Conversely, elevated O₃ concentrations entering stomata trigger oxidative stress responses in plants, leading to decreased stomatal conductance. While this defensive mechanism limits further O₃ absorption, it simultaneously restricts CO₂ uptake efficiency, ultimately impairing photosynthetic performance and carbon sequestration capacity. This review investigates the ecological effects of O₃ and CO₂ interactions, focusing on vegetation-mediated gas exchange and its feedback on atmospheric composition. This review examines flux monitoring technologies and modeling approaches, highlighting how O₃ pollution influences CO₂ assimilation and how plant responses contribute to atmospheric O₃ regulation. Key factors such as species traits, growth conditions, and environmental variables are analyzed to evaluate how they modulate these interactions. By synthesizing current understanding of vegetation-regulated O₃ and CO₂ interactions, this study provides important insights for pollution control and sustainable ecosystem management.