Space–Time Evaluation of Atmospheric Black Carbon in Chinese Urban Environment: Influence of Land Use and Air Pollution Policies

High black carbon (BC) levels due to combustion processes pose a severe air pollution issue in China, especially in urban agglomerations. Although the BC levels, source apportionment, and radiative impacts have been extensively analyzed, limited research has investigated the effect of ongoing human activities and mitigation strategies on the changes in BC levels in urban regions of East China. In this study, the trends of BC in China are analyzed from 1980 to 2022, using BC concentrations and BC-aerosol optical depth (BC AOD ) data from Modern-Era Retrospective Analysis for Research and Applications version 2 (MERRA-2) and Copernicus Atmosphere Monitoring Service (CAMS) from 2005 to 2022. Eight representative areas, including six densely populated and highly polluted urban regions (Beijing–Tianjin–Hebei [BTH], Central China [CC], Sichuan Basin [SCB], Yangtze River Delta [YRD], North East China [NEC], and Pearl River Delta [PRD]), were selected for the analysis. A significant, but variable increase in BC concentrations was observed during 1980–2021. There was an increase in BC between 1980–1990 and 1999–2007, but it remained stable from 1990 to 2000 and dropped sharply after 2010. The average increase in BC concentrations was approximately ten times higher in East China than in West China, signaling the increase in population, traffic, and demand for energy consumption for a society with progressive increasing gross domestic product. BC dynamics in urban regions were highly associated with population density, gross domestic product, and land use land cover (LULC) changes. The declining trend in BC concentrations during the last decade was mainly attributed to the air pollution mitigation policies implemented by the Chinese government, having as a result the decrease in combustion emissions especially in urban areas. Our findings highlight the need for further studies on the impact of BC on human health and regional climate change in China.