Spatio-temporal variation of the relationship between air pollutants and land surface temperature in the Yangtze River Delta Urban Agglomeration, China

The urban heat island effect and air pollution have become widespread environmental problems in urban areas. We investigated the spatial-temporal distributions of the daytime and nighttime LST and air pollutant concentrations and their interactions in the Yangtze River Delta urban agglomeration (YRDUA) from 2015 to 2020. We found that the LST of the southern cities was higher than the north, and the heat island shows a "Z" pattern of distribution. O3 pollution occurs in the warm summer, while other air pollutant concentrations are higher in the winter. Air pollution concentrations are higher in the northern cities than in the south. The daytime and nighttime LST were positively correlated with O3 concentrations, with the correlation being strongest in spring and autumn. The PM2.5, PM10, SO2, NO2, and CO concentrations show negative correlations with the daytime and nighttime LST, with the strongest interactions in winter. This study provides a better reference for understanding the relationship between LST and air pollutant concentrations. In addition, the issue of air pollution and integrated urban heat island mitigation strategies in the region deserve further study.