NIHR CLEAN-Air(Africa) Unit “Clean modern energy for all”. Benefitting health, society, environment and climate in sub-Saharan Africa to achieve the 2030 Sustainable Development Goals. Globally 3.8 billion people rely on polluting fuels (e.g. wood, charcoal, kerosene) for cooking. Household air pollution (HAP) from burning these fuels caused 2.3 million premature deaths in 2019 (more than HIV/AIDS, malaria and tuberculosis). With 695,000 premature deaths and 38 million Disability-Adjusted-Life-Years (DALYs) in 2019, Sub-Saharan Africa (SSA) bears a disproportionate fraction (30%) of the global HAP-related disease burden. The NIHR CLEAN-Air(Africa) Unit will accelerate the understanding of HAP-related disease burden through a unique set of studies that will (i) strengthen national health systems for community health prevention of HAP-related disease and (ii) provide evidence-based recommendations for population transition to clean household and institutional energy. The Unit will leverage the expertise of community health workers (CHWs), an overlooked frontline health promotion workforce, via implementation of a national Ministry of Health (MoH) led training of CHWs in HAP, health and prevention. This will include (i) development of curricula/ job aids in Cameroon, Rwanda and Uganda, (ii) creation of a digital platform for CHW training and health surveillance to maximise reach of training and (iii) effective rollout of training in Kenya to 140,000 CHWs. To inform national strategies to achieve UN Sustainable Development Goal (SDG) 7 (ensuring universal access to clean, modern household energy by 2030) and address the associated negative health, gender, and climate impacts of reliance on polluting cooking fuels, the Unit will collaborate with several international organisations (e.g. WHO, World Food Programme) to investigate innovations that have potential for rapid scale in SSA. We will run 5 randomised controlled trials to test technological (pay-as-you-cook LPG smart meters and pressure cookers), nutritional (pre-cooked, vitamin enhanced beans) and behavioural (cooking classes) innovations for addressing barriers to adoption and exclusive use of clean cooking fuel for households (n=620) and schools (3,600 pupils) in East Africa. A focus on institutional cooking in schools is particularly novel, with a high degree of HAP exposure to school cooks and pupils offering high value for money in terms of population-level reductions in polluting fuel use. An in-depth mixed-methods evaluation (n=400) will be conducted of a successful social entrepreneur company in Kenya providing LPG access to rural women (20,000 current users) to understand their ability to facilitate microfinance for clean cooking. Through Africa's first Air Pollution Centre of Excellence at KEMRI, we will use state-of-the-art air monitoring equipment to elucidate relationships between exposure to HAP and respiratory disease (spirometry study; n=500) and cardiovascular health (heart rate variability study using wearable technology; n=100) in Cameroon. The Unit will also quantify hidden burdens related to gender inequity (time poverty from fetching firewood) and burns/ scalds (establishment of clinical/ primary care surveillance). Research activities will begin by Year 2 after Unit launch and start of the capacity building program in Year 1. The Unit's academic trainee programme will run from Years 1-4. Our dissemination foci on (i) population awareness raising and (ii) rapid knowledge translation of research evidence to policy will be enabled through close engagement with ministerial stakeholders steering national energy strategy.