2018~2020年北京市交通监测站点大气污染特征分析

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（NO₂、CO、O₃、PM_2.5、PM₁₀）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PM₁₀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NO₂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NO₂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.O₃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NO₂下降最为显著.交通站点NO₂、CO、PM_2.5平均降幅比城市评价站点高出了4.81%、10.21%、4.38%.

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

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, NO₂, CO, O₃, PM_2.5 and PM₁₀, 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 NO₂, CO, O₃, 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. O₃ 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 NO₂, CO, PM_2.5 and PM₁₀ 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 NO₂ decreased most in comparison to the same period in 2019. At traffic stations evaluated, the average decreases among NO₂, CO and PM_2.5 were 4.81%, 10.21% and 4.38% respectively higher than those at the urban stations evaluated.