Air pollution and health in Rwandan and Kenyan schools cooking with polluting fuels: a cross-sectional impact study

School meals across Sub-Saharan Africa are typically prepared using biomass on inefficient stoves, resulting in high air pollution levels that might affect learners and staff. However, there is a paucity of air pollution health-related research in African schools. This study, conducted in seven schools in Rwanda and four schools in Kenya, assessed 1) levels of carbon monoxide (CO) and fine particulate matter (PM_2.5) in school kitchens, classrooms (three, at different distances from the kitchen), playgrounds and personal among learners and catering staff; and 2) the prevalence of acute air pollution health-related symptoms and knowledge and perceptions of air pollution among learners and staff. For Rwanda and Kenya respectively, median 24-h PM_2.5 levels were 263 and 1480 μg/m³ for kitchens and 63 and 68 μg/m³ for classrooms. In Rwanda, median personal PM_2.5 exposure levels were 354 μg/m³ for cooks and 86 μg/m³ for leaners. In Kenya, median personal PM_2.5 exposures were 1280 μg/m³ for cooks and 99 μg/m³ for leaners. Median CO levels in the kitchens were 1.8 and 23 and for cooks 3 and 14.8 mg/m³ for Rwanda and Kenya respectively. Surveys with learners (n = 526 and n = 302), catering staff (n = 45 and n = 28), and teachers (n = 21 and n = 12) for Rwanda and Kenya, respectively, demonstrated a high prevalence of self-reported air pollution-related headaches, eye irritation, and cough. The elevated air pollution levels and associated prevalence of health issues underscore the urgent need to accelerate transition to clean energy in African schools.