2018~2020年北京市交通监测站点大气污染特征分析

Characteristics of the atmospheric pollutants at traffic monitoring sites in Beijing during 2018~2020

基于北京市34个空气质量监测站点收集的5种主要污染物浓度(NO_(2)、CO、O_(3)、PM_(2.5)、PM_(10))数据,对2018~2020年北京市5个交通站点污染物浓度进行分析,并与11个城市评价站点及2个背景点(密云水库、定陵)进行对比.结果表明:(1)3a间各污染物浓度年际变化总体呈下降趋势,除PM_(10)外,交通站点各污染物浓度降幅均大于城市评价站点.2020年交通站点NO_(2)降幅最大,比2018年下降了31.37%.除个别时期外,5种污染物浓度在交通站点比城市评价站点普遍高出3%~50%.且以NO_(2)最为突出.(2)2018~2020年各监测站点不同污染物浓度的季节变化特征表现不同.O_(3)夏季高、冬季低,最高值出现在2018年6月;其余4种污染物浓度基本表现为冬季高、夏季低;2018年3月受沙尘及不利气象条件影响,污染物浓度出现了极高值.(3)为研究新冠肺炎疫情对交通污染排放的影响,比较了5种污染物的浓度变化.与2019年同期相比,疫情后三个阶段的NO_(2)下降最为显著.交通站点NO_(2)、CO、PM_(2.5)平均降幅比城市评价站点高出了4.81%、10.21%、4.38%.

To explore the impacts on both air pollution and to monitor traffic pollution in Beijing,18 air quality monitoring stations were selected from the 34 existing stations,including 5 traffic stations,11 urban stations evaluated and 2 background stations(Miyun and Dingling).We compared the concentrations with the 5 major pollutants,NO_(2),CO,O_(3),PM_(2.5) and PM_(10),at the selected stations during 2018~2020,we found that these five pollutants decreased during these three years,and the decreases were generally 3%~50%higher in the traffic stations evaluated than in the urban stations evaluated.The decreases of NO_(2),CO,O_(3),and PM_(2.5) were more important at the traffic stations evaluated than at the urban stations evaluated.The seasonal variation at each monitoring station was also different.O_(3) was higher in summer and lower in winter,and the highest value in June 2018.The comparison to the concentrations of the other four pollutants NO_(2),CO,PM_(2.5) and PM_(10) were also higher in winter and lower in summer.In March 2018,the concentration of pollutants was extremely higher due to dust and adverse meteorological conditions.To investigate the influence of COVID-19,the concentrations for these five pollutants were compared in 2019 and 2020.The results showed that NO_(2) decreased most in comparison to the same period in 2019.At traffic stations evaluated,the average decreases among NO_(2),CO and PM_(2.5) were 4.81%,10.21%and 4.38%respectively higher than those at the urban stations evaluated.