Evaluating the effects of surface O3 on three main food crops across China during 2015–2018

In order to tackle China’s severe air pollution issue, the government has released the “Air Pollution Prevention and Control Action Plan” (known simply as the “Action Plan”) since 2013. A recent study reported a decreased trend in PM₂.₅ concentrations over 2013–2017, but O₃ pollution has become more serious. However, the effects of surface O₃ on crops are unclear after the implementation of the “Action Plan”. Here, we evaluated the potential negative effects of surface O₃ on three main food crops (winter wheat, maize and rice) across China during 2015–2018 using nationwide O₃ monitoring data and AOT40-yield response functions. Results suggested that mean O₃ concentration, AOT40 and relative yield loss in China showed an overall upward trend from 2015 to 2018. During winter wheat, maize, single rice, double-early rice, and double-late rice growing seasons, mean O₃ concentration in recent years ranged from 38.6 to 46.9 ppb, 40.2–43.9 ppb, 39.3–42.2 ppb, 33.8–40.0 ppb, and 35.9–39.1 ppb, respectively, and AOT40 mean values ranged from 8.5 to 14.3 ppm h, 10.5–13.4 ppm h, 9.8–11.9 ppm h, 5.2–9.2 ppm h, and 8.0–9.5 ppm h, respectively. O₃-induced yield reductions were estimated to range from 20.1 to 33.3% for winter wheat, 5.0–6.3% for maize, 7.3–8.8% for single rice, 3.9–6.8% for double-early rice and 5.9–7.1% for double-late rice. O₃-induced production losses for winter wheat, maize, single rice, double-early rice, and double-late rice totaled 39.5–88.2 million metric tons, 12.6–21.0 million metric tons, 9.5–11.3 million metric tons, 1.2–1.8 million metric tons, and 2.2–2.7 million metric tons, respectively, and the corresponding economic losses totaled 14.3–32.0 billion US$, 3.9–6.5 billion US$, 3.9–4.6 billion US$, 0.5–0.7 billion US$, and 0.9–1.1 billion US$, respectively. Our results suggested that the government should take effective measures to reduce O₃ pollution and its effects on agricultural production.