Transport and Source Distribution Characteristics of Major Air Pollutants During COVID-19 in Yangquan,China
At the beginning of 2020,COVID-19 pandemic took the lead in China.The Chinese government imposed unprecedented lockdown measures,which provides an opportunity to study the relationship between regional air pollution characteristics and transport.The daily and hourly mean mass concentrations of the main atmospheric pollutants(NO2,PM2.5 and O3)from six state-controlled stations for atmospheric environmental quality in Yangquan City,Shanxi Province were selected to obtain the variation characteristics of the atmospheric pollutant concentrations from 2019 to 2021.The impact of the lockdown on the main air pollutants in February 2020 was analyzed,and the potential source contributions of these three air pollutants in Yangquan City during the research period were quantified by combining the 48 h backward trajectory simulated by HYSPLIT model,the potential source contribution factor method(PSCF)and the concentration weighted trajectory(CWT).The results showed that during the study period,the average concentration of NO2 and PM2.5 showed a downward trend overall,and the mean concentration of NO2 in 2021 rose slightly compared with that in 202,but the overall level was lower than that in 2019.The concentration of O3 was rising year by year,which was speculated to be caused by the photochemical formation of O3 in the troposphere.The cluster analysis of backward trajectory showed that the atmospheric pollutants in February 2019 and 2021 mainly came from the transport of the eastern air mass,while in 2020 mainly came from the west.The mean mass concentration of NO2 and PM2.5 on the cluster track was positively correlated with the cluster track of the track,while O3 had no obvious correlation.According to the characteristics of monthly mean level of pollutants in February,it was speculated that the lockdown could reduce the concentration of these three major pollutants in 2020,and the reduction in 2021 could be attributed to the role of atmospheric environment control measures implemented in local and surrounding areas.The distribution of potential sources of NO2 and PM2.5 was regionalized year by year.The potential source distribution of NO2 was mainly the contribution of local Yangquan City,Jinzhong City and Taiyuan City,while the potential source distribution of PM2.5 was characterized by the contribution of local Shanxi Province,Shandong Province,Beijing-Tianjin-Hebei region,Henan Province and Shaanxi Province.The distribution of potential sources of O3 mainly came from the contributions of local Yangquan City and Shijiazhuang City in the east,which also verified that it came from local photochemical generation to some extent.
万方数据
维普
