Emission Inventories Underestimate Black Carbon in the Global South as Revealed by Comparison of Simulations with Measurements from a Globally Distributed Network

YUXUAN REN, Randall Martin, Christopher Oxford, Dandan Zhang, Xuan Liu, Ann M. Dillner, Rajan K. Chakrabarty, Sina Hasheminassab, David Diner, Joshin Kumar, Valerie Viteri, Washington University in St. Louis

     Abstract Number: 263
     Working Group: Carbonaceous Aerosols

Abstract
Characterization of black carbon (BC) on a global scale is essential for understanding its impact on climate forcing and human health. However, high uncertainty persists in global BC simulations and inventories. Here, we evaluate BC simulations for the year 2019 from a global chemical transport model (GEOS-Chem) in its high-performance configuration using the Community Emissions Data System (CEDS) emission inventory versus measurements from the globally distributed Surface Particulate Matter Network (SPARTAN) and other available measurements. Results indicate a high degree of consistency (r2 = 0.81; slope = 1.26) of the simulation with SPARTAN measurements across primarily developed countries in northern midlatitudes and Australia, but pronounced discrepancy across the Global South (r2 = 0.19, slope= -0.52). Notably, Africa and South Asia exhibit substantial underestimations, with average simulated-to-observed ratios of 0.11 in Dhaka, Bangladesh, 0.15 in Addis Ababa, Ethiopia, and 0.26 in Ilorin, Nigeria. The discrepancy between simulations and observations is primarily attributed to limitations in existing emission inventories, and using alternative inventories including the EDGAR and HTAP within the model yields similar results. These findings motivate renewed attention to the challenging tasks of characterizing BC emissions from developing countries.

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