A large-scale study across schools in Rwanda and Kenya has found dangerously high levels of air pollution from biomass-fuelled cooking, raising serious health concerns for millions of children and staff across Sub-Saharan Africa.
The research, led by the University of Liverpool, Kenya Medical Research Institute, and Rwanda Biomedical Center, was conducted across seven schools in Rwanda and four schools in Kenya.
Here researchers measured exposure to harmful pollutants including fine particulate matter (PM2.5) and carbon monoxide (CO) in school kitchens, classrooms, and playgrounds, as well as among cooks and learners. Surveys also assessed the prevalence of acute air pollution–related symptoms and perceptions of air quality among students, teachers, and catering staff.
Results revealed alarmingly high pollution levels:
- Kitchen air pollution far exceeded international health guidelines, with PM2.5 levels 11.9 times the World Health Organization (WHO) 24-hour interim target in Rwanda and 19.5 times in Kenya.
- Personal exposure levels were highest among cooks, reaching median PM2.5 levels of 1,280 μg/m³ in Kenya and 354 μg/m³ in Rwanda, when the 24-hour interim target is 75 μg/m³. This is likely to carry significant health risks including for respiratory and cardiovascular disease.
- Children faced exposure of 99 μg/m³ in Kenya and 86 μg/m³ in Rwanda, well above WHO recommendations.
- Health impacts were widespread, with high rates of self-reported headaches, eye irritation, and cough among both pupils and staff.
With 368 million children in Africa receiving a school meal daily – almost all prepared using polluting biomass stoves – the findings underscore an urgent public health challenge.
Willah Nabukwangwa, a researcher from the Kenya Medical Research Institute (KEMRI) working for the NIHR CLEAN-Air(Africa) Global Health Research Unit said: “Our study is the first comprehensive assessment of air pollution and health in Sub-Saharan African schools. The levels of air pollution we observed are unsafe and put both children and school staff at risk of serious illness, yet often overlooked. These findings highlight the urgent need to accelerate the transition to clean cooking solutions in schools across the continent.”
Dr Vasileios Matthaios, an air pollution expert from the Department of Public Health Policy and Systems at the University of Liverpool, who supported the research added: “It is clear that air pollution produced from cooking with wood affects the school environment and exposes children to high levels of fine particulate matter (PM2.5). Our future research will assess the impacts of interventions to reduce this exposure on both respiratory health and cognitive performance.”
Mr Reverien Rutayisire, CAA PhD student, Rwanda Biomedical Centre and research co-lead added: “Our impact evaluation of clean cooking interventions using gas and electricity in Rwandan schools provides critical evidence to inform government climate and health policies. We are carefully disseminating our findings to key ministerial stakeholders.”
The research was conducted as part of the NIHR CLEAN-Air(Africa) Global Health Research Unit a £7million program co-directed by the University of Liverpool and KEMRI.
As part of CLEAN-Air(Africa) research, work will now evaluate the health and environmental benefits of shifting schools to clean cooking fuels such as electricity, solar and liquefied petroleum gas (LPG). Such interventions could significantly reduce air pollution exposure, improve health outcomes, and reduce the heavy reliance on unsustainable biomass fuels.
The paper, ‘Air pollution and health in Rwandan and Kenyan schools cooking with polluting fuels: a cross-sectional impact study’ was published in Environmental Research (DOI: 10.1016/j.envres.2025.122619).
Both featured photographs were taken at Kwa Njenge Primary School, Nairobi.