Assessment of yield and economic losses for wheat and rice due to ground-level O3 exposure in the Yangtze River Delta, China

In recent years, ground-level O3 and its potential risks on agricultural crops have attracted worldwide attention from both society and academic community. According to the hourly O3 concentration data in 24 cities of the Yangtze River Delta during wheat (16 March to 29 May 2015) and rice (20 July to 20 October 2015) growing seasons, we estimated the yield and economic losses of wheat and rice resulted by O3 exposure using O3 exposure-response functions based on AOT40 (accumulated hourly O3 concentration above 40 ppb, this exposure index is the current standard for vegetation protection against O3). The results showed that the O3 mean concentration during wheat and rice growing seasons ranged from 28.2 to 44.3 ppb and 27.6-44.2 ppb, respectively. The AOT40 values during wheat and rice growing seasons ranged from 4.33 to 15.82 ppm h and 7.64-25.15 ppm h, respectively. Relative yield loss ranged from 9.86 to 36.05% for wheat and 7.25-23.87% for rice. The total crop production loss for wheat and rice amounted to 552.55 × 104 tons and 535.06 × 104 tons, respectively. The total economic loss amounted to 209.31 × 107 US$ for wheat and 237.03 × 107 US$ for rice. Our study revealed the potential regional risk of ground-level O3 exposure to crops in the Yangtze River Delta. Therefore, some effective measures should be taken urgently to reduce the negative effects of O3 on crop productivity.