Yield and economic losses of winter wheat and rice due to ozone in the Yangtze River Delta during 2014–2019

Abstract

Ground-level ozone (O3) is the main phytotoxic air pollutant causing crop yield reduction in China. As the main grain producing area in China, the Yangtze River Delta (YRD) is facing serious O3 pollution. This study analyzed the hourly ground-level O3 observation data of 158 stations from 2014 to 2019 in YRD, and grain production data of 193 districts and counties. The exposure-response relationships based on AOT40 (accumulated hourly O3 concentration above 40 ppb) was used to estimate the yield loss and economic loss of two food crops (winter wheat and rice). This study used spatial interpolation and calculated the specific data values of each district and county in order to improve the assessment reliability. For years 2014–2019, averaged O3 concentration during the 75 days growing period of rice and wheat were 33.1–50.6 ppb and 32.2–48.0 ppb, AOT40 value were 5.2–12.0 ppm h and 4.6–9.4 ppm h, and the averaged relative yield losses were 4.9%–11.4% and 9.4%–19.3%, respectively. The trend of O3 in the YRD in a six-year period peaked in 2016 and 2017 for rice and winter wheat, respectively. During 2014–2017, the average estimated yield loss of rice was 2445 Mt. accounting for about 9.1% of the actual production, and the average estimated economic loss was about 1037 million USD; for winter wheat, it was 2025 Mt, 20.4% and 736 million USD, respectively. These results urge governments to provide effective policies and measures to control O3 pollution.