邯郸市新冠疫情前后空气质量指数(AQI)对比与疫情防控期间大气污染特征分析

Comparison of air quality index(AQI) before and after COVID-19 in Handan City and analysis of air pollution characteristics during COVID-19 prevention and control

2020年初COVID-19疫情爆发,我国采取一系列管控措施使大气污染物排放量明显降低.为了解疫情期间减排活动下邯郸市大气污染特征,采用统计学变量分析方法与特征雷达图对疫情爆发前(12月、1月)、疫情防控期间(2-4月)、疫情防控后(5月、6月)以及2019年同期大气污染情况进行对比分析.并进一步估算防控期间大气污染物的减排量,通过后向轨迹聚类分析气团的迁移轨迹来探讨人为减排对空气质量的影响.结果表明,2020年2月疫情管控开始后,环境空气质量与2019年同期相比明显好转,2月份AQI值降幅约为50%,3、4月份两年差距逐渐缩小;疫情防控期间较疫情爆发前空气质量也有较大幅度提升,防控结束后AQI值有小幅度回弹;防控期间PM_(2.5)、PM_(10)、SO_(2)、NO_(2)、CO的日平均浓度值均有较大幅度下降,在2月份下降最为明显,降幅分别为51%、55%、62%、41%、33%;O_(3)8 h平均浓度与气温呈显著正相关(0.747),疫情期间浓度呈上升趋势,在4月底达到的峰值(238μg·m^(-3)).北京市空气污染相对较轻,邯郸市与石家庄市较为严重,整体上受颗粒物的污染较明显.邯郸市2、3、4月份特征雷达图属于偏综合型,2月燃煤、生物质燃烧排放的污染物偏高,4月份来自工厂的NO_(2)和SO_(2)浓度偏高.疫情防控前期各污染物排放量均有较大幅度降低,与2019年2月的气团移动轨迹来源特征相似,说明人为减排对环境空气质量提升效果显著.

The COVID-19 epidemic have been broken out in early 2020,and China took a series of control measures to significantly reduce the emission of air pollutants during the epidemic.In order to understand their pollution characteristics in Handan city under the emission reduction during the epidemic period,statistical variable analysis method and characteristic radar map were used to analyzed the air pollution situation before the outbreak(December-2019 and January-2020),during the prevention and control period(February to April-2020),after the prevention and control period(May and June-2020)and compared with the same period of 2019.The impact of anthropogenic emission reduction on air quality was discussed through backward trajectory clustering analysis of air mass migration trajectory.Our results showed that after the outbreak control began in February-2020,the air quality was significantly improved compared with the same period in February-2019.The AQI value was decreased by approximately 50%in February,and the gap between March and April gradually narrowed.During the prevention and control period in February,the average concentrations of PM_(2.5),PM_(10),SO_(2),NO_(2) and CO were decreased significantly as 51%,55%,62%,41%,and 33%,respectively.During in these period,mean concentration of O_(3) for 8 h was significantly positively correlated with air temperature(0.747).O_(3) concentration was increased during the epidemic period and reached the peak at the end of April(238μg·m^(-3)).On the whole,air pollution by particulate matter is more obvious.The characteristic radar map of Handan city in February,March and April is relatively comprehensive.During February,the pollutants discharged from coal burning and biomass combustion are on the high side,while the NO_(2) and SO_(2) concentration from factories is on the high side in April.In the early stage of epidemic prevention and control,the emission of all pollutants were decreased significantly,which was similar to the air mass movement trajectory and source characteristics in February-2019,indicating that man-made emission reduction had a significant impact on the improvement of air quality.