Regional Assessment Of The Impact Of Ozone Pollution On Winter Wheat And Rice Yields In My Country

Since ozone pollution is more and more serious and the polluted region is expanding in China,the crop yield reduction caused by surface ozone has been concerned due to its strong oxidation and phytotoxicity.As the main food crop,winter wheat has been confirmed to be an ozone sensitive crop and rice a moderately sensitive crop.The yield reduction in wheat and rice will seriously threaten the food security in China.This paper used the hourly ozone concentration data from urban air quality monitoring stations(national control stations)during2014 and 2020,and the detailed growth phenology in the main winter wheat production areas,to investigate the ozone pollution status during the wheat growth period.The ozone dose-yield response function based on field measurements in China is used to estimate the yield loss and economic loss of winter wheat and rice caused by ozone pollution in the Yangtze River Delta.The main results are shown below.(1)During the growth period of winter wheat,serious ozone pollution occurred based on the average during 2015 and 2020,showing a decrease from Eastern China to western region,and extremely serious pollution was found in the Beijing-Tianjin-Hebei region,the Yangtze River Delta region,and the Fenwei Plain.Nationwide,the annual average of M7(the mean O₃concentration during 09:00–16:00 at a certain growth period)was between 39.8-47.7 ppb,and M12(the mean O₃concentration during 07:00–19:00 at a certain growth period)was between39.3 ppb-47.3 ppb during 2015 to 2020.The annual average AOT40(the accumulation of hourly mean ozone values over 40 ppb during daylight hours)was between 10.0-15.2 ppm h,and the annual average SUM06(accumulative value of O₃concentration greater than 60 ppb during the growth period)was between 15.1-24.6 ppm h,and the average W126(the sigmoidally weighted exposure index)was between 13.0-20.6 ppm h.This indicates that the current ozone concentration in China has exceeded the threshold for normal wheat growth,suggesting that current ambient O₃may threaten winter wheat production.Based on the current ozone concentration and crop planting,the yield reduction of rice and wheat in the Yangtze River Delta due to ozone pollution was estimated from 2014 to 2019.The annual average ozone concentration was 33.1-50.6 ppb and 32.2-48.0 ppb,the AOT40annual value was 5.2-12.0 ppm h and 4.6-9.4 ppm h,and the annual averaged relative yield loss was 4.9%-11.4%and 9.4%-19.3%,during the growth period of rice and wheat from 2014to 2019,respectively.The highest levels of O₃pollution during the growth period of rice and winter wheat were in 2016 and 2017,respectively.During the period 2014-2019,the average yield loss of rice was 2479 Mt,accounting for about 9.2%of the actual production,and the average economic loss was about 1.0 billion USD;the average yield loss of winter wheat was2197 Mt,accounting for 21.9%of the actual production.The average economic loss was about 776 million USD.Current results provide scientific basis and theoretical reference for the ecological risk assessment by air pollution.