Evaluating the effects of ground-level O3 on rice yield and economic losses in Southern China

Ground-level ozone (O₃) pollution and its impact on crop growth and yield have become one of the serious environmental problems in recent years, especially in economically active and densely populated areas. In this study, rice yield and the associated economic losses due to O₃ were estimated by using observational O₃ concentration ([O₃]) data during growing seasons in Southern China. O₃-induced yield losses were calculated by using O₃ exposure metrics of AOT40 and M7. The spatial distribution of these two metrics is relatively consistent, the highest areas located in the Yangtze River Basin. Under the current O₃ level, during double-early rice, double-late rice and single rice growing seasons, the relative yield losses estimated with AOT40 (M7) were 6.8% (1.2%), 10.2% (1.9%) and 10.4% (2.0%), respectively. O₃-induced rice production loss for double-early rice, double-late rice and single rice totaled 2.4 million metric tons (0.4 million metric tons), 4.3 million metric tons (0.7 million metric tons) and 11.0 million metric tons (1.9 million metric tons) and associated economic losses were 108.1 million USD (18.3 million USD), 190.2 million USD (32.4 million USD) and 486.4 million USD (82.9 million USD) based on AOT40 (M7) metric. This study indicates that regional risks to rice from O₃ exposure and provide quantitative evidence of O₃-induced impacts on rice yields and economic losses across Southern China. Therefore, the establishment of scientific O₃ risk assessment method is of great significance to prevent yield production and economic losses caused by O₃ exposure. Policymakers should strengthen supervision of emissions of O₃ precursors to mitigate the rise of O₃ concentration, thereby reducing O₃ damage to agricultural production.