East African Megacity Air Quality: Rationale and Framework for a Measurement and Modeling Program

Abstract Air pollution in Africa is a significant public health issue responsible for 1.1 million premature deaths annually. Sub-Saharan Africa has the highest rate of population growth and urbanization of any region in the world, with substantial potential for future emission growth and worsening air quality. Accurate and extensive observations of meteorology and atmospheric composition have underpinned successful air pollution mitigation strategies in the Global North, yet Africa in general and East Africa in particular remain among the most sparsely observed regions in the world. This paper is based on the discussion of these issues during two international workshops, one held virtually in the United States in July 2021 and one in Kigali, Rwanda, in January 2023. The workshops were designed to develop a measurement, capacity building, and collaboration strategy to improve air quality-relevant measurements, modeling, and data availability in East Africa. This paper frames the relevant scientific needs and describes the requirements for training and infrastructure development for an integrated observing and modeling strategy that includes partnerships between East African scientists and organizations and their counterparts in the developed world. Significance Statement Air pollution is a leading environmental risk factor in East Africa that is expected to worsen with rapid urbanization and economic growth occurring in the region. The unique emission sources will impact atmospheric composition and chemistry and are of significant current interest to understand their impact on climate and air quality mitigation efforts everywhere. There is a need to quantify emission trends from different regions of the world and develop reliable methods for inventories. Relationships between scientists from both the Global North and the Global South will help to advance and implement measurements and to build global atmospheric chemistry capacity.