Spatial–temporal variations of NO2 pollution in Shandong Province based on Sentinel-5P satellite data and influencing factors

Abstract

With the rapid development of the social economy, nitrogen dioxide (NO₂), a trace gas that is an air pollutant, has dual impacts on human health and climate change. In this study, the Google Earth Engine platform is used to retrieve the vertical column concentration inverted by the Tropospheric Monitoring Instrument (TROPOMI) sensor onboard the Sentinel-5 Precursor satellite, and the characteristics of the spatial–temporal distribution of the tropospheric NO₂ column concentration in Shandong Province from 2019 to 2023 are analyzed. The results show that there is a high correlation between the NO₂ column concentration retrieved from the TROPOMI and the NO₂ concentration observed at ground-level monitoring points in Shandong Province (R = 0.8289). The distribution of the NO₂ column concentration in Shandong Province exhibits a progressive structure of “high in the west and low in the east” with significant spatial heterogeneity. In addition, the fluctuation in the NO₂ column concentration in Shandong Province has obvious cyclical and seasonal characteristics, and the change rate is “summerflat in spring and autumn, high in winter and low in summer.” The results of the geographical detectors indicate that temperature has the greatest influence on the NO₂ column concentration in Shandong Province (q = 0.5). The geographically weighted regression model indicated that the NO₂ column concentration was negatively correlated with the topography, temperature, and precipitation, and the correlation coefficients are −0.010, −0.952, and −0.330, respectively. It is positively correlated with the intensity of human activities, the degree of urbanization of the land, and the population density, and the correlation coefficients are 0.1610, 0.982, and 0.001, respectively.