Summer and Fall 2023 Update of an Ongoing Aethalometer-Based Black Carbon Measurement and Source Apportionment Campaign at Long-Term Monitoring Sites in Addis Ababa, Ethiopia as Part of the Multi-Angle Imager for Aerosols (MAIA) Investigation

L. DREW HILL, Sina Hasheminassab, Jeff Blair, Steven Blair, Ivan Iskra, Tesfaye Mamo, Araya Asfaw, David Diner, Aethlabs

     Abstract Number: 571
     Working Group: Aerosols Spanning Spatial Scales: Measurement Networks to Models and Satellites

Abstract
Particulate matter (PM) smaller than 2.5 microns in diameter (PM_2.5) is a well-known health hazard. Previous investigations have demonstrated that the risk imposed by exposure to PM_2.5 varies by its chemical composition. NASA’s Multi-Angle Imager for Aerosols (MAIA) investigation seeks to add better characterize the toxicity the major constituent components of PM_2.5 by integrating satellite observations with ground-based speciated PM measurements at a 1 km resolution in 11 global Primary Target Areas (PTAs). One such component is black carbon (BC) – an aerosol commonly produced by the combustion of petroleum or biomass fuels. We present findings from surface measurements of PM_2.5 and BC taken in the Addis Ababa PTA, adding data from summer and early autumn 2023 to an ongoing analysis of the first-ever year-long continuous BC measurements in Addis Ababa, which began approximately in the spring season of 2022. Preliminary analysis from Summer and early Fall of 2022 show average BC levels between 5 - 10 µg/m³ and suggest BC may contribute approximately 10-20% of ambient PM_2.5 mass concentrations in the region during this period – a BC/PM_2.5 fraction higher than values observed at the same time in other more well-studied PTAs like Beijing and Los Angeles. Source-specific contributions to BC concentrations will be estimated using the Aethalometer Model, and meteorological data will be used to infer policy-relevant information about these sources.