Fresh Air, Fast Feet: Nairobi City Marathon Leads Africa’s Green Race Revolution

By Robert Kibet

Nairobi, Kenya, July 2, 2025: This Sunday, as thousands of runners take on the streets of Nairobi in the third edition of the Nairobi City Marathon, they’ll not only be chasing personal records, but also running through one of the most advanced air-quality-monitored urban race routes on the continent.

Thanks to a partnership between the Stockholm Environment Institute (SEI), the United Nations Environment Programme (UNEP), Athletics Kenya, and key infrastructure stakeholders like Moja Expressway, this year’s race continues to lead the charge in making athletics events safer, cleaner, and more sustainable.

Over nine real-time air quality monitoring sensors have been installed along the marathon route by SEI. These sensors are silently at work, collecting critical data to assess levels of pollutants and athletes’ exposure to air pollution as the race unfolds.

“We at SEI are proud to have supported sustainability initiatives for the Nairobi City Marathon since 2022,” said Dr. Anderson Kehbila, Program Leader for Energy and Climate Change at SEI. “This year, we’ve installed nine air quality monitoring sensors along the marathon route.”

“These sensors help us assess pollutant levels and athletes’ exposure to air pollution. The latest data confirms that pollution levels are low during the early morning hours of race day, meaning athletes run in a safe, clean environment.”

A Long-Term Climate Health Vision

Air pollution is an invisible threat that continues to challenge cities across Africa. In Nairobi, growing vehicle traffic, industrial emissions, and open waste burning have contributed to increasingly hazardous air quality. But initiatives like these demonstrate how sport can become a powerful tool for public health and environmental awareness.

“In terms of going deeper into air quality, this is being led by SEI in partnership with the United Nations Environment Programme,” said Dr. Kehbila. “The key here is to get this data, which we’ve done, and we’ve presented it to Athletics Kenya, who have used it as a resource to submit their sustainability and climate change action report to World Athletics.”

Athletics Kenya President Lt. Gen. (Rtd) Jackson Tuwei praised the innovation, saying:

“We appreciate the partnership with the Stockholm Environment Institute and UNEP for providing air quality sensors along the marathon route. This data not only helps us safeguard athlete health but also strengthens our commitment to sustainable sports events.”

This sustainability-linked monitoring not only benefits race-day planning but also contributes to a broader data repository for environmental and urban health advocacy.

From Expressway to Clean Airways

Even beyond the race, partners like Moja Expressway are pushing the boundaries of climate responsibility by installing sensors at transport hubs used daily by thousands of commuters.

“Through Athletics Kenya, we have partnered with UNEP and the Stockholm Environment Institute to fit air quality monitors in five of our eleven stations,” said Jean May, spokesperson for Moja Expressway.

“We are hoping that even after the marathon, we can keep the conversation going, because urban greening is not just a marathon event — it’s something that should be happening across Nairobi.”

This type of investment highlights how climate action tied to a single sporting event can have ripple effects across an entire city’s infrastructure.

Making the Data Public

Data from these sensors is transmitted directly to an online platform hosted by UNEP, offering real-time air quality readings. The platform is open to the public, providing critical information for everyone, from elite athletes and coaches to schoolchildren, joggers, and health-conscious residents.

“Our platform is not just for scientists,” Dr. Kehbila explained. “It’s for everyday Nairobi residents to understand the air they breathe and make informed choices.”

Beyond real-time readings, SEI and UNEP are exploring the integration of this data into the Kenya Meteorological Department’s early warning system, which could enable the public to receive air pollution alerts alongside traditional weather forecasts.

Leading by Example

By embedding environmental intelligence into one of Kenya’s premier athletic showcases, the Nairobi City Marathon is shaping up to be a model of sustainable urban sport.

“This year’s race is about more than medals,” said a race official. “It’s about giving athletes and spectators a reason to care about clean air, climate justice, and their environment.”

This growing ecosystem of partnerships between sport, science, and infrastructure is positioning Nairobi as a global leader in climate-conscious event planning — one sensor and one stride at a time.

And as the marathon grows each year, organizers are looking to embed even more sustainability metrics, from clean mobility and waste reduction to energy efficiency, ensuring that every mile contributes not just to the finish line, but to a healthier city.