Black carbon in major global source areas from 2000 to 2023: Spatiotemporal variation, vertical distribution, and...

Black carbon (BC) emissions in regions such as Eastern China (EC), the Indian Subcontinent (IS), Sub-Saharan Africa (SSA), and Central South America (CSA) notably affect global air quality, climate change, and human health, owing to intensive anthropogenic activities and biomass burning. Using modern-era retrospective analysis for research and applications, version 2 reanalysis data and emission inventories, we quantified the long-term spatiotemporal variations and vertical distributions of atmospheric BC and anthropogenic emissions across various sectors (2000-2023). In addition, we explored the formation mechanisms of extreme cases in representative cities (such as Beijing, Delhi, Luanda, and Sucre). The results indicated consistent annual trends in BC surface mass concentrations and column mass densities. In the EC and IS, BC primarily originated from anthropogenic emissions, whereas in the SSA and CSA, biomass combustion predominated. Notable regional differences in anthropogenic BC emissions were observed, with all sectors in SSA exhibiting a markedly increasing trend. Seasonal patterns of BC were influenced by local meteorological conditions, emissions from anthropogenic sources, and biomass burning. In EC and IS, BC concentrations declined rapidly with decreasing air pressure, whereas in SSA and CSA, the decline was slower in the lower atmosphere, with a rapid decrease at an altitude of approximately 700 hPa. High-concentration BC events in the representative cities are linked to interactions between local emissions, adverse meteorological conditions, and atmospheric circulation. Our study quantified the long-term BC characteristics in major global source regions from multiple perspectives, providing valuable scientific insights for both regional and global atmospheric environmental research and management.