How athletes and scientists work together toward clean air can have repercussions locally and across national borders. SEI, in collaboration with partners from UNEP Regional Office for Africa, CIFOR-ICRAF and ROAM Electric, demonstrated how a sustainable environment can enhance athletic performance.
The Jubilee Live Free Race, powered by the Grand Nairobi Bike Race (GNBR), is an annual regional cycling event hosted in Nairobi that draws participants from Kenya, Uganda, Tanzania, Burundi and more than 30 other nationalities. On race day this year, 5 October, while cyclists powered through the streets of Nairobi, SEI and other sustainability partners were engaged in a different kind of assessment – monitoring the city’s air quality.
Launched in 2021, the Jubilee Live Free Race has grown into one of East Africa’s most anticipated sporting events, offering categories for professional cyclists, para-cyclists, families and children, including the 75 km Main Race, 45 km Black Mamba and Para-Cycling races, 15 km Family Fun Ride and Kiddie Race. This year’s event was not only a vibrant display of athletic prowess – it was also a continuation of Nairobi’s conversation around urban health and mobility.
At the pre-race press conference, event partners shared personal stories of growing up with bicycles as their first form of transport. They spoke of the unfiltered joy of cycling in their childhood villages on the iconic “black mamba” bicycles, first introduced in the 1930s and able to carry up to a tonne. They recalled their mothers ferrying them around on the back seat while running errands, and how bikes gave them their first taste of freedom and independence. For many, the bicycle was the original, effortless form of transport – a stark contrast to the congestion and pollution that characterize Nairobi today.
These nostalgic stories highlighted how perspectives on mobility have shifted. While contemporary Nairobi often equates mobility with car ownership, traffic and high emissions, the partners reminded participants that transport was once inherently low-carbon. That memory now underpins a renewed resolve: the path to sustainable urban transport begins by re-prioritizing the original, healthy and simple solution – the bicycle.
“Promoting biking is not only about exercise; it is also about actively carving out space for sustainable mobility, reducing carbon footprints and creating a more sustainable, resilient urban environment,” said Ngongang Danube, SEI Africa research fellow, during his presentation at the press conference on SEI’s contribution to the “sustainability bus” during the race.
For athletes pushing their bodies to the limit, the quality of the air they breathe is paramount. SEI deployed its specialized air-quality monitoring tools, using a combination of stationary sensors strategically placed along the Jubilee Live Free Race route. Mobile sensors were attached to bicycles from SEI’s sustainability partner, World Agroforestry.
The goal was twofold: to gather real-time data and to visually demonstrate air quality and heat conditions in Nairobi during the race. The resulting data provided an evidence-based snapshot of the environment in which the athletes competed.
Air quality and temperature readings during the Grand Nairobi Bike Race 2025 (06:00–12:00) at Nyayo Stadium show PM₂.₅ and PM₁₀ levels well below the WHO guideline of 15 µg/m³, with temperatures peaking near 31°C.
Graphic: SEI air quality monitoring.
The insights gathered fed directly into SEI Africa’s “Sport for Climate Action – Sustainability Framework”, which embeds environmental sustainability and climate resilience into the planning, delivery and legacy of sporting events and infrastructure, ensuring health, equity and environmental integrity for athletes, spectators and host communities.
Exposure to pollutants, even at moderate levels, can reduce lung function, increase recovery time and pose long-term health risks to athletes and spectators alike. By monitoring conditions during the race, SEI turned the event into a living laboratory – transforming a sporting competition into an advocacy tool.
The air-quality monitoring sensor installed at Nyayo Stadium, which served as both the starting and finishing point of the Grand Nairobi Bike Race 2025, provided insights into environmental conditions during the event. Between 06:00 and 12:00, measured concentrations of PM₂.₅ (5.6 µg/m³) and PM₁₀ (6.5 µg/m³) remained well below the World Health Organization (WHO) 2021 guideline of 15 µg/m³ for PM₂.₅, confirming that the air quality was generally safe for participants and spectators. This may have been due to the race route being closed off the previous night, preventing vehicles from passing, and because the event took place on a Sunday, when Nairobi’s traffic is typically lighter.
Despite these favourable conditions, the findings highlighted the importance of continued vigilance and proactive safeguarding during mass sporting events, where exposure to elevated temperatures – reaching up to 31°C – and localized emissions can pose health risks to athletes and the public. The results served as a reminder to policymakers of the direct link between urban planning, climate action and the wellbeing of the city’s inhabitants.
This year’s edition saw close to 3 500 participants, with the winner of the elite race walking away with a grand prize of KES 100 000.
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Other publication / This report examines key weather events during the year and puts them in the context of 1991–2020 climatology.
Project / This project strengthens Somalia’s national air quality governance through policy development and targeted capacity building
