基于TROPOMI的石家庄市NO_(2)柱浓度时空分布及来源分析

Spatio-temporal Distribution and Source Analysis of NO_(2) Column Density in Shijiazhuang City Based on TROPOMI

为探讨石家庄市NO_(2)柱浓度时空分布及潜在污染源区,该文利用2019-2021年L2级别的TROPOMI二氧化氮数据、石家庄市8个国控点环境自动监测站的NO_(2)、O_(3)、PM_(2.5)浓度数据和气象要素数据以及全球数据同化系统中的气象数据,对石家庄市NO_(2)时间变化、空间分布、污染传输通道城市以及潜在源贡献区进行分析。结果表明:石家庄市NO_(2)浓度年内变化趋势呈“U”型,季节性明显,NO_(2)浓度冬季(13.33×10^(15) molec/cm^(2))>秋季(12.76×10^(15) molec/cm^(2))>春季(4.96×10^(15) molec/cm^(2))>夏季(4.09×10^(15) molec/cm^(2));NO_(2)浓度空间表现为“主城区高、四周低”的椭圆带状分布,并形成主城区-鹿泉-正定、赞皇-元氏-高邑和深泽-辛集3个污染中心。通过与气象因子的相关性分析得知,NO_(2)浓度与气压、温度、降水量均具有显著相关性,相关系数分别为0.815、-0.739、-0.520,相对湿度和风速的影响不显著,相关系数分别为-0.325、-0.326。通过潜在源分析得出邢台、邯郸、山东西北部、河南北部、内蒙古中部以及蒙古国南部地区是石家庄地区的污染物传输通道范围,长治、晋中、太原、安阳、郑州、焦作、新乡、邢台、邯郸等地均为石家庄市的高污染贡献概率、高污染贡献值地区。

In order to investigate the spatial-temporal distribution of NO_(2) column density and potential pollution sources in Shijiazhuang City,Level 2 TROPOMI NO_(2) data of 2019-2021,NO_(2),O_(3) and PM_(2.5) 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 channel and potential source contribution areas of NO_(2).Results revealed that the annual variation of NO_(2) density in Shijiazhuang City tended to be U-shape,with obvious seasonality.The seasonal values of NO_(2) density in the order of decreasing magnitude were winter(13.33×10^(15) molec/cm^(2))>autumn(12.76×10^(15) molec/cm^(2))>spring(4.96×10^(15) molec/cm^(2))>summer(4.09×10^(15) molec/cm^(2)).NO_(2) 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 NO_(2) 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,northern 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 contribution value were high to Shijiazhuang City.