“大气十条”实施对2013—2017年大气气溶胶⁃辐射相互作用的影响

Impact of the implementation of the“Ten Statements of Atmosphere”on the atmospheric aerosol⁃radiation interaction during 2013-2017

为应对严重的大气污染问题,我国于2013年颁布并实施了严格的《大气污染防治行动计划》(“大气十条”).本研究利用在线耦合的区域大气化学传输模型WRF⁃Chem进行数值模拟,研究了2013—2017年“大气十条”实施期间大气气溶胶⁃辐射相互作用(Aerosol⁃Radiation Interaction,ARI)强度的变化及其对空气质量的影响,并量化分析了排放和气象条件变化对气溶胶⁃辐射相互作用强度变化和空气质量改善的相对贡献.研究发现,“大气十条”实施后ARI对PM_(2.5)质量浓度的增强效应明显减弱,ARI效应的减弱导致2017年全国平均PM_(2.5)浓度相较2013年下降了2.7μg·m^(-3),占PM_(2.5)浓度总降幅的9.1%.在这一过程中污染减排起了主导作用,约占ARI效应减弱导致全国平均PM_(2.5)浓度下降的88%,气象条件变化的贡献约占12%.在季节尺度上,冬季ARI效应减弱最为明显,使得2017年冬季全国月平均PM_(2.5)浓度同比2013年下降了12.1%.在区域尺度上,ARI效应的减弱对京津冀区域PM_(2.5)浓度的影响最为显著,使得2017年该区域平均PM_(2.5)浓度相较2013年下降了2.8μg·m^(-3),占该区域PM_(2.5)浓度总降幅的9.9%.2013—2017年,ARI效应对京津冀区域冬季重污染天气的影响程度也明显降低.以2013年1月和2017年1月为例,ARI效应使得这两个月内强霾事件期间区域日平均PM_(2.5)浓度峰值分别增加了47.6μg·m^(-3)和33.7μg·m^(-3).研究表明“大气十条”实施后ARI对PM_(2.5)质量浓度的增强效应明显减弱,从而进一步推动了全国及重点区域PM_(2.5)浓度的下降,带来了额外的空气质量改善效益.

In order to deal with its serious air pollution problem,China issued and implemented the strict“Action Plan for the Prevention and Control of Air Pollution”(“Ten Statements of Atmosphere”)in 2013.In this research,the online coupled WRF⁃Chem model was used to study the changed level of the atmospheric aerosol⁃radiation interaction(ARI)and the impact on air quality,as well as the relative contributions of emission reductions and meteorological changes to aerosol-radiation interaction and air quality improvement during the implementation period of the“Ten Statements of Atmosphere”from 2013 to 2017.It is found that,after the implementation of the“Ten Statements of Atmosphere”,the impact of the ARI effect on PM_(2.5) mass concentration was obviously weakened.The weakened ARI effect led to a decrease of 2.7μg·m^(-3) in the national average PM_(2.5) mass concentration in 2017 compared with that in 2013,accounting for 9.1%of the total reduction of PM_(2.5) concentration.In this process,emission reductions played a dominate role,accounting for about 88%of the reduction in the national average PM_(2.5) concentration caused by the weakened ARI effect,and the contributions of meteorological changes accounted for about 12%.On seasonal scale,the ARI effect was weakened mostly in winter,which led to a decrease of 12.1% of the national average monthly PM_(2.5) concentration in winter 2017 compared with that in winter 2013.On regional scale,the weakened ARI effect had the most significant impact on PM_(2.5) concentration in the Beijing⁃Tianjin⁃Hebei(BTH)region,which led to a decrease of 2.8μg·m^(-3) in the regional average PM_(2.5) concentration in 2017 compared with that in 2013,accounting for 9.9%of the total reduction of PM_(2.5) concentration in this region.During 2013—2017 the impact of the ARI effect on heavy pollution winter weather in the BTH region was also significantly reduced.For example,in January 2013 and January 2017,the ARI effect increased the peak value of the regional average daily PM_(2.5) concentration by 47.6μg·m^(-3) and 33.7μg·m^(-3) during severe haze episodes,respectively.The research shows that the ARI effect on PM_(2.5) mass concentration was significantly weakened after the implementation of the“Ten Statements of Atmosphere”,and thus further promoted the reduction of PM_(2.5) mass concentration and yielded additional air quality improvement benefits.