Air pollution is often framed as an environmental or urban planning issue. Yet the evidence is unequivocal: the air we breathe is directly linked to cancer risk. For the oncology community, this is not a peripheral concern; it is central to prevention, equity, and long-term cancer control. The World Health Organization and the International Agency for Research on Cancer have classified outdoor air pollution and fine particulate matter (PM2.5) as Group 1 carcinogens. This places polluted air in the same category as tobacco smoke. In other words, air pollution is not just associated with cancer but it causes cancer.
The Invisible Risk with Visible Consequences
Air pollution is made up of microscopic particles and gases released from vehicle emissions, industrial processes, biomass fuel use, and open waste burning. The most dangerous of these are PM2.5 which penetrates deep into the lungs and bloodstream, carrying toxic chemicals that damage DNA, trigger chronic inflammation, disrupt normal cellular function.
Over time, these processes increase the risk of lung cancer, with growing evidence linking air pollution to breast, colorectal, liver, and bladder cancers.
Kenya’s Reality: The Numbers Behind the Risk
In Kenya, air pollution is measurable and rising:
- National average PM2.5 levels are approximately 13-14 µg/m³, which is nearly three times higher than the safe limits recommended by the World Health Organization
- Urban centers such as Nairobi experience consistently moderate but harmful air quality levels, driven by traffic emissions and urban activity
- Trends suggest increasing pollution levels, reflecting rapid urbanization and limited emission controls
These figures translate into real and growing health risks, including increased cancer burden over time.
The Equity Dimension: Who Breathes the Most Risk?
Air pollution is a profound health equity issue. The highest exposures are often found among populations with the fewest resources to mitigate risk. In Kenya, communities living and working around the Dandora Dumpsite face daily exposure to toxic emissions from the open burning of mixed waste, including plastics and hazardous materials. Similar realities exist in informal settlements where households rely on biomass fuels for cooking and heating. These communities are not only more exposed but are also less likely to access early detection and treatment services. This creates a double burden: higher risk and poorer outcomes.
Why Oncology Cannot Stay Silent
Historically, cancer prevention efforts have focused on well-known risk factors such as tobacco use, infections, and lifestyle behaviors. While these remain critical, environmental determinants like air pollution must now be integrated into cancer control strategies.
Oncology has a unique role to play:
- Translating evidence into public understanding
- Integrating environmental risk into cancer programs
- Advocating for prevention-focused policy
Through the work of the Kenya Network of Cancer Organizations, we have seen how bringing a cancer lens to air pollution strengthens both awareness and action.
Lessons from Community Engagement
- Local media works: translating science into relatable language drives awareness
- Start with lived experience: communities already understand the impact of polluted air
- Avoid technical-only messaging: connect science to daily life
- Pair awareness with action: communities need realistic alternatives and policy support
Adding Value Without Duplication
Cancer organizations do not need to duplicate environmental efforts. Instead, they can:
- Bring a health and cancer prevention lens
- Amplify community voices
- Support data linkage between exposure and cancer outcomes
- Convene cross-sector collaboration
This complementary role strengthens the national response.
A Call to Action
Clean air is not a luxury. It is a fundamental determinant of health and a critical component of cancer prevention. In Kenya, where pollution levels already exceed safe limits, the urgency is clear. Addressing air pollution is not just environmental protection but is cancer control.
Closing Reflection
The fight against cancer is no longer confined to hospitals and laboratories. It extends to our homes, our streets, and our policies. We cannot treat our way out of a problem that is rooted in the air itself.
Clean air is cancer prevention and the time to act is now.
Written by Phoebe Ongadi