减排措施与气象因子对2013—2019年中国大陆地区PM_(2.5)浓度变化的贡献

Contributions of emission reduction measures and meteorological factors to the changes in PM_(2.5) concentration over China's Mainland from 2013 to 2019

利用地面气象观测站数据计算的大气自净能力指数(Atmospheric Self-cleaning ability Index,简称ASI)和环境监测站PM_(2.5)实测数据,评估了中国大陆地区2014—2019年相对于2013年("大气国十条"实施初期)污染物总体排放率的相对变化,给出了PM_(2.5)浓度削减量中气象条件和减排措施的相对贡献.研究结果显示,2014年全国排放率总体已下降,2017年各地区全面实现减排,较2013年全国平均减排36.11%,2019年减排幅度进一步加大,至48.50%,其中中东部地区整体减排力度大于西部和东北部地区.2015和2016年秋冬,重点区域持续性重污染频发现象的出现是不利气象条件背景与减排略有放松共同作用的结果,但持续的减排措施对于遏制空气质量的恶化起到了积极作用.2019年,京津冀、汾渭平原、长三角等9个重点区域PM_(2.5)浓度相较2013年明显降低,高空气质量至少一半以上的原因来源于人为减排,气象因子的贡献相对较小,仅为3%~18%,一些区域气象因子对PM_(2.5)的改善甚至起到负作用.2013年"大气国十条"实施以来,全国各重点区域有效的污染排放控制确实对空气质量改善起到了决定性作用.本文研发的分离气象和减排措施对PM_(2.5)浓度变化中相对贡献的方法,使用的定量关系简单、明确,所使用的数据客观、可靠,有利于快速估算和决策.

Based on the observed PM_(2.5) concentration data and the calculated atmospheric self-cleaning ability index(ASI)from meteorological data,The change of pollutant emission rate during 2014—2019,relative to 2013(i.e.,the initial period of the implementation of the Air Pollution Prevention and Control Action Plan by the State Council of China),by applying the urban atmospheric load index was established.Meanwhile,the individual contributions of meteorological conditions and emission reduction measures to the reduction of PM_(2.5) concentration were investigated.The results are as follows:The reduction effects initially appeared in 2014 in most parts of China.Emission reduced substantially in 2017 and 2019 across the whole country,with the averaged emission reduction rate being 36.11%and 48.50%respectively relative to 2013.The overall emission reduction in the central and eastern China was greater than that in the western and northeast regions.In the autumn and winter of 2015,the adverse meteorological conditions and eased emission reduction mutually caused the high frequency of severe pollutions in key areas.However,the persistent emission control definitely contributed to prevent the further deterioration of air quality.In 2019,the PM_(2.5) concentration apparently declined in 9 regions including Beijing-Tianjin-Hebei region,Fenwei Plain and Yantze River Delta.At least half of the contributions for clean air came from the emission reduction.The contribution of meteorological factors was relatively small,only between 3%and 18%,and even negative in some regions.Since the Air Pollution Prevention and Control Action Plan was promulgated by the State Council of China in 2013,substantial pollution emissions in key regions have indeed played a decisive role in improving air quality.Reliable and objective data and explicit mathematical relationship were the main two advantages of the method for separating the individual contributions of meteorological factors and emission reductions to PM_(2.5) concentration changes developed in this study,which was conducive to fast decision-making.