摘要
The authors evaluated and compared the behavior of PM2.5 with respect to NOx and NH3 emission changes in high(the year 2013)and low(the year 2018)SO2 emission cases.Two groups of simulations were conducted based on anthropogenic emissions from China in 2013 and 2018,respectively.In each group of simulations,a respective 25%reduction in NOx and NH3 emissions were assumed.A sensitivity factor(β)was defined as the relative change in PM2.5 concentration due to 1%change in NOx or NH3 emissions.In the high SO2 emissions case,PM2.5 was more sensitive to NH3(0.31)emissions change than NOx(0.21).Due to the significant decrease in SO2 emissions from the high to low SO2 emissions case,the sensitivity of PM2.5 to NOx increased to 0.33,while its sensitivity to NH3 decreased to 0.22.The result implies that now and in the future,PM2.5 is/will be less sensitive to NH3 emissions change,while NOx emissions control is more effective in reducing the surface PM2.5 concentration.Seasonally,in the low SO2 emissions case,the sensitivities of PM2.5 to NOx and NH3 in winter were higher than those in summer,indicating that to dealwith severewinter hazemore attention should be paid to the emissions control of inorganic PM2.5 precursors,especially NOx.
随着大气污染防治计划的实施,我国SO2排放量从2013年的25.4 Tg下降至2018年的10.5 Tg。SO2排放的大幅变化是否会影响PM2.5对NOx和NH3排放的敏感性尚不清楚。为此,本研究采用GEOSChem全球大气化学传输模式,评估了中国东部不同SO2排放水平下PM2.5对NOx和NH3敏感性的变化。结果表明:2013年, PM2.5对NH3的敏感性(0.31)比NOx(0.21)更强。2013~2018年,由于SO2排放大幅下降, PM2.5对NOx的敏感性上升至0.33,而对NH3的敏感性则下降到0.22。因此,在较低的SO2排放情景下,考虑到PM2.5对NH3的敏感性降低,进一步消减NOx排放可能对降低PM2.5浓度有更好的效果。
基金
This work was supported by the National Natural Science Foundation of China[grant number 41805098].
