Spatio-temporal Distribution and Source Analysis of NO2 Column Density in Shijiazhuang City Based on TROPOMI

LIU Bohan; YUAN Jinguo; LI Yancui; WANG Jingzhi

doi:10.19672/j.cnki.1003-6504.0591.23.338

Abstract：In order to investigate the spatial-temporal distribution of NO2 column density and potential pollution sources in Shijiazhuang City,Level 2 TROPOMI NO2 data of 2019-2021,NO2,O3 and PM2.5 concentration data from eight national automatic monitoring stations and meteorological elements data in Shijiazhuang City,as well as meteorological data from global data assimilation system were used to analyze the temporal variation,spatial distribution,pollution transmission chan-nel and potential source contribution areas of NO2.Results revealed that the annual variation of NO2 density in Shijiazhuang City tended to be U-shape,with obvious seasonality.The seasonal values of NO2 density in the order of decreasing magni-tude were winter(13.33×1015 molec/cm2)＞autumn(12.76×1015 molec/cm2)＞spring(4.96×1015 molec/cm2)＞summer(4.09×1015 molec/cm2).NO2 density appeared to be the elliptic distribution with the pattern of"higher in the main urban areas of Shijiazhuang and lower in the surrounding(county level)regions";and three pollution centers were formed as follows:main urbar area-Luquan District-Zhengding County,Zanhuang County-Yuanshi County-Gaoyi County,and Shenze County-Xinji County.The correlation analysis with meteorological factors showed that NO2 concentration was significantly correlated with air pressure,temperature and precipitation,and the correlation coefficients were 0.815,-0.739 and-0.520,respectively.The influences of relative humidity and wind speed were not so remarkable,and the correlation coefficients were respectively-0.325 and-0.326.Potential source analysis showed that Xingtai City,Handan City,northwestern Shandong Province,north-ern Henan Province,central Inner Mongolia Autonomous Region and southern Mongolia were the areas of the pollutant transmission channels to Shijiazhuang.In addition,the cities of Changzhi,Jinzhong,Taiyuan,Anyang,Zhengzhou,Jiaozuo,Xinxiang,Xingtai and Handan,etc.,were the areas where both the pollution contribution probability and pollution contri-bution value were high to Shijiazhuang City.