Spatio-temporal variation and influencing factors of air quality in the main urban area of Taiyuan before and after the COVID-19
Background,aim,and scope The recurrence of the COVID-19 has caused a major impact on people's lives worldwide,and many cities around the world have implemented control measures to significantly reduce air pollutant emissions.The implementation of man-made control measures provides a favorable opportunity to study air quality and comparative analysis of the influencing factors.Taiyuan,located in the central part of Shanxi Province and the northern part of the Jinzhong Basin,adopted strict control measures during the COVID-19 in Mar.and Apr.2022,but the spatio-temporal variation and influencing factors of air quality in the main urban area of Taiyuan are still unclear.This study focuses on the air quality characteristics and pollutant causal mechanisms in the main urban area of Taiyuan before and after the COVID-19,in order to provide data support and reference for understanding the urban air quality conditions and formulating environmental management.Materials and methods This study used several methods,including Kriging interpolation,Pearson correlation analysis and HYSPLIT trajectory model,to analyze the characteristics of spatio-temporal changes in air quality before and after the COVID-19 in the main urban area of Taiyuan in 2022,as well as its influencing factors.Results During the COVID-19,PM2.5 and PM10 decreased significantly compared with the same period in 2021.O3 showed a trend of increasing month by month,the concentration of other pollutants changed less,and the overall air quality improved.In addition,the PM2.5,CO,and SO2 showing the distribution characteristics of"low in the northwest and high in the southeast",and PM10 concentration is characterized by"low in the west and high in the east".Discussion During the COVID-19,due to multiple factors such as reduced human activities and increased spring wind,the contribution rate of PM2.5 pollution decreased compared to that of before.However,the contribution rate of PM10 has increased,suggesting that primarily affected by the dust weather in northern China during spring.Notably,the contribution rate of NO2 pollution showed a downward trend,which may be mainly related to the reduction of industrial and mobile sources.It is interesting that the contribution rate of O3 was less affected during the COVID-19 and was affected by the warmer temperatures.The air flow causes the transmission of pollutants between different regions.Taiyuan was principally affected by the long-distance transport in the northwest direction and the short-distance transport in Jinzhong in the south of Shanxi before and during the COVID-19.Conclusions The air quality was better during the COVID-19 due to the reduction of mobile source pollution emissions and the influence of meteorological factors.Recommendations and perspectives This study suggests air quality can be improved by reducing emission sources through multiple measures.However,meteorological factors also have an impact on air quality.Thus,the human and natural factors should be considered comprehensively to control air quality during a public security emergency period.These insights offer a scientific foundation for future strategies in mitigating air pollution in cities located in north-central China.
COVID-19Taiyuanair qualityHYSPLIT trajectory model
万方数据
维普
