中国东部地区典型臭氧污染过程防控敏感性及减排情景研究

Assessment of ozone sensitivity and emission reduction scenarios in typical pollution processes in eastern China

近年来,我国东部地区夏季臭氧污染问题日渐凸显,成为影响空气质量、环境改善的重要因素之一,为量化评估臭氧前体物减排对臭氧污染的影响,本文以2021年6月19—30日中国东部地区臭氧污染过程为例,应用空气质量模型CMAQ-DDM方法与卫星遥感反演算法分析了东部地区臭氧浓度对人为源前体物排放敏感性的响应程度,并对臭氧前体物设置不同削减比例开展减排情景模拟,结果表明:1)2021年6月19—30日中国东部出现了一次长时间区域性臭氧污染过程,大部分城市达轻度至中度污染水平;2)整个污染时段东部地区主要以VOCs(Volatile Organic Compounds,挥发性有机物)控制区或VOCs与NO x协同控制区为主,模型模拟与卫星反演结果具有较好的一致性,污染过程前段(19—25日)东部地区对VOCs敏感性较高,污染后段(26—30日)大部分地区转为VOCs和NO x协同控制区,特别是河南、安徽、江苏部分地区,对NO x敏感性提高较为显著;3)在相同减排比例条件下(VOCs∶NO x=2∶1),减排幅度越大,臭氧降幅越大,当VOCs削减比例由20%提高到40%时,臭氧浓度降幅由1.7%增大至3.6%;由VOCs和NO x协同减排(2∶1)过渡为强化NO x减排(1∶1)的分阶段控制优于单一的减排控制方案,臭氧改善率平均增强0.1%;仅削减高架源NO x对臭氧降幅不显著。

In recent years,ozone pollution in the summer has increasingly become problem a significant concern affecting air quality and environment in eastern China.This study aims to quantitatively evaluate the impact of reducing ozone precursor emissions on ozone pollution.Using the ozone pollution episode in eastern China from June 19 to 30,2021,as a case study,we use CMAQ-DDM air quality model and satellite remote sensing inversion algorithm to analyze ozone concentration sensitivity to anthropogenic precursor emissions in the eastern region.Different reduction scenarios for ozone precursors are simulated by setting different reduction ratios.The findings reveal the following:1)From June 19 to 30,2021,an extended regional ozone pollution event occurred in eastern China,with most cities experiencing slight to moderate pollution levels;2)Throughout the pollution period,the eastern region was predominantly influenced by VOC control or a combination of VOC and NO x control.Model simulations and satellite inversions exhibited good agreement.In the early stage of the pollution event(June 19-25),the eastern region was highly sensitive to VOCs,while in the latter stage(June 26—30),it transitioned into an area where coordinated control of VOCs and NO x was crucial,especially in Henan,Anhui,and Jiangsu;3)When applying the same emission reduction ratio(VOCs∶NO x=2∶1),larger emissions reductions led to greater reductions in ozone levels.Increasing the VOC reduction ratio from 20%to 40%resulted in an ozone concentration reduction ranging from 1.7%to 3.6%.Phased emission reduction strategies outperformed single-period reduction plans,achieving a 0.1%increase in the ozone improvement rate.Reducing only elevated NO x sources did not significantly decrease ozone concentrations.