Kenyan teenagers Fredrick Njoroge Kariuki and Miron Onsarigo have been named the African winners of The Earth Prize 2026 for their project, HewaSafi. Their innovation is a low-cost vehicle exhaust filter designed to reduce harmful emissions from urban transport. The duo will receive $12,500 to advance their solution, which aims to improve air quality in Kenya's cities.
A Personal Mission Against Pollution
The inspiration for HewaSafi is deeply personal, rooted in direct experiences with air pollution's health impacts. For Fredrick Kariuki, the project stemmed from a battle with bronchitis aggravated by poor air quality, which transformed his view of pollution into a direct threat. Co-creator Miron Onsarigo was similarly motivated by seeing illness from vehicle fumes normalized in his hometown of Kisumu.
Their mission addresses a critical public health crisis, as air pollution poses a major threat across the continent. A prominent health study linked air pollution to approximately 1.1 million deaths in Africa during 2019. HewaSafi represents a grassroots effort to mitigate a key source of this widespread environmental hazard, particularly from urban transport systems.
An Ingenious and Sustainable Design
HewaSafi, meaning “clean air” in Swahili, is a multi-stage exhaust system built from accessible and sustainable materials. The filter combines maize cobs, coconut shells, and agricultural waste with a living algae component to capture over 90 percent of particulate matter. This unique composition is designed to effectively reduce harmful emissions from vehicles common on Kenyan roads.
Unlike expensive and theft-prone catalytic converters, HewaSafi offers an affordable alternative with a prototype costing approximately $125. The project’s focus on low-cost, local materials is a key aspect of its design, ensuring it can be manufactured sustainably. This approach lowers the financial barrier to adoption and promotes a circular economy by repurposing agricultural waste.
Future Plans and Commercial Viability
After successful pilot tests with a local matatu association, the HewaSafi team is focused on refining and scaling their technology. Their immediate goal is to collaborate further with transport operators, starting with the Eastleigh Matatu SACCO. This partnership is crucial for testing the filter's reliability and effectiveness in real-world urban conditions.
The innovators envision a complete product line called the HewaSafi Emission Control System, with versions tailored to specific needs like motorcycles and minibuses. To ensure affordability, the team plans to offer these products through flexible installment payment plans. As regional winners, they now compete for the global title, which will be decided by a public vote.
The HewaSafi project is a powerful example of practical, localized climate technology emerging from Africa. Fredrick Kariuki and Miron Onsarigo have developed a solution that addresses the immediate reality of urban transport instead of waiting for a complete EV transition. Their success is a significant step toward creating a scalable tool to improve public health across the continent.