摘要
Surface ozone(O_(3))poses significant threats to public health,agricultural crops,and plants in natural ecosystems.Global warming is likely to increase future O_(3)mainly by altering atmospheric photochemical reactions and enhancing biogenic volatile organic compound(BVOC)emissions.To assess the impacts of the future 1.5 K climate target on O_(3)concentrations and ecological O_(3)exposure in China,numerical simulations were conducted using the CMAQ(Community Multiscale Air Quality)model during April-October 2018.Ecological O_(3)exposure was estimated using six indices(i.e.,M7,M24,N100,SUM60,W126,and AOT40f).The results show that the temperature rise increases the MDA8 O_(3)(maximum daily eight-hour average O_(3))concentrations by∼3 ppb and the number of O_(3)exceedance days by 10-20 days in the North China Plain(NCP),Yangtze River Delta(YRD),and Sichuan Basin(SCB)regions.All O_(3)exposure indices show substantial increases.M24 and M7 in eastern and southern China will rise by 1-3 ppb and 2-4 ppb,respectively.N100 increases by more than 120 h in the surrounding regions of Beijing.SUM60 increases by greater than 9 ppm h^(−1),W126 increases by greater than 15 ppm h^(−1)in Shaanxi and SCB,and AOT40f increases by 6 ppm h^(−1)in NCP and SCB.The temperature increase also promotes atmospheric oxidation capacity(AOC)levels,with the higher AOC contributed by OH radicals in southern China but by NO_(3)radicals in northern China.The change in the reaction rate caused by the temperature increase has a greater influence on O_(3)exposure and AOC than the change in BVOC emissions.
地表臭氧(O_(3))对公众健康,农作物以及自然生态系统构成重大威胁.全球变暖会增强大气光化学反应以及增加生物源挥发性有机化合物(BVOC)排放,从而导致O_(3)浓度增加为了评估未来1.5 K气候目标对中国O_(3)浓度以及生态O_(3)暴露的影响,在2018年4月至10月期间使用CMAQ模型进行了数值模拟.使用六个指标(即M7,M24,N100,SUM60,W126和AOT40f)估算生态O_(3)暴露.结果表明,在华北平原长江三角洲和四川盆地地区,温度升高使每日最大:8小时平均O_(3)浓度增加约3 ppb,O_(3)超标天数增加10-20天所有O_(3)暴露指标均显著增加.中国东部和南部的M24和M7将分别增加1-3ppb和2-4ppb.北京周边地区的N100增加超过120小时陕西和四川盆地的SUM60增加超过9ppm h^(−1),W126增加超过15ppm h^(−1),华北平原和四川盆地的AOT40f增加6ppm h^(−1).温度升高还提升了大气氧化能力(AOC)水平,在中国南部较高的AOC由羟基自由基贡献,面在中国北部则由硝基自由基贡献由温度升高引起的反应速率变化对O_(3)暴露和AOC的影响比BVOC排放增加带来的贡献更大。
基金
supported by the National Natural Science Foundation of China[grant numbers 42277095 and 42021004].
