The science behind Kip Keino Classic being hosted in April
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Reading Time: 4min | Tue. 07.04.26. | 16:38
For years, April has been the default month for the Kip Keino Classic. Now, science explains why
The Kip Keino Classic returns on Friday, 24 April at Nyayo National Stadium and for the first time, the event will run under floodlights from 4 PM to 9 PM, a historic shift that reflects a deeper, data-driven understanding of performance, environment, and health.
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But the bigger story lies in why April has always been its home.
For years, April has been the default month for the Kip Keino Classic. Now, science explains why.
Speaking to Mozzart Sport, Ngongang Wandji Danube Kirt, a research fellow at the Stockholm Environment Institute, explained that this timing is no coincidence, but the result of sustained environmental monitoring and analysis.
“We have partnered with Athletics Kenya under a program on sustainability in sport. One of the key pillars of this initiative is understanding how climate change affects performance and air quality within sports infrastructure, while also examining how sporting activities, in turn, impact the environment. It is a two-way relationship,” he explained.
Through a partnership with Athletics Kenya, researchers have spent the last four to six years collecting real-time air quality data across major sporting venues, including Nyayo Stadium, Moi International Sports Centre, Kasarani, and Ulinzi Sports Complex.
At the heart of this research is a critical pollutant: PM2.5 (particulate matter 2.5), tiny airborne particles that can penetrate deep into the lungs and significantly affect human health and athletic performance.
“Over the past four to six years, formalised through a Memorandum of Understanding signed in 2022, we have been monitoring sports facilities across the country. The goal is to capture real-time data on air quality around these venues,” Kirt said.
Through backward analysis of four years of data, April emerges as the cleanest month in Nairobi in terms of air quality. Pollution levels during this period fall well below thresholds set by the World Health Organisation (WHO), making it the safest window for both athletes and spectators.
“Through backward analysis, we found that April consistently records the lowest air pollution levels compared to other months of the year. This makes it the most suitable period to host an event like the Kip Keino Classic,” he noted.
Several factors explain this. April typically records lower pollution levels, with reduced concentrations of PM2.5 compared to other months, creating cleaner air for both athletes and spectators.
The weather is also more moderate, with cooler temperatures that support endurance and aid recovery. In addition, the onset of rainfall helps to settle airborne pollutants, improving overall air clarity, while balanced humidity levels prevent the excessively dry or harsh conditions that can negatively affect performance.
“From a climatological perspective, April also offers favourable conditions. It is not excessively dry, temperatures are lower, and there is some rainfall. These factors combine to create an optimal environment for athletic performance,” Kirt added.
This combination creates what scientists consider an optimal performance environment.
Why location matters
Nyayo Stadium sits within a dense urban environment where pollution sources are largely unavoidable.
In Nairobi, air quality is primarily affected by transport emissions, which remain the dominant contributor due to fuel combustion from vehicles, alongside open waste burning and industrial activity, all of which combine to shape the atmospheric conditions around the stadium.
“In Nairobi, major sources of air pollution include transport, open waste burning, and industrial activity, with transport being the most significant contributor,” he explained.
Nearby construction and traffic can influence air quality readings within a one-kilometre radius of the stadium. However, continuous monitoring ensures that organisers understand these patterns and can plan accordingly.
“For Nyayo Stadium, its location within a busy urban setting, coupled with nearby construction, can influence the readings. However, our focus is to capture as much data as possible within the stadium’s immediate environment,” Kirt said.
Why the evening shift is strategic
The move to an evening schedule under floodlights is also rooted in science.
Data shows that in April, air pollution around Nyayo Stadium reaches its lowest levels between 6 PM and 9 PM. This makes evening competition the safest and most athlete-friendly option.
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“Notably, hosting the event in the evening is highly strategic. Over the past four years, data shows that between 6 PM and 8 PM, or even up to 9 PM, air pollution levels around Nyayo Stadium are at their lowest in April,” he revealed.