Air quality is being notably degraded by a slew of pollutants, black carbon (BC), carbon monoxide (CO), sulfur dioxide (SO2), volatile organic compounds (VOCs), organic carbon (OC), carbon dioxide (CO2), nitrogen oxides (NOx), and methane (CH4). This has deleterious effects on human health and agricultural productivity, among other adverse impacts. Previous emission estimates have identified road transport as an important source of several of these pollutants in Africa. Regional emission inventories highlight the potential for substantially larger increases in the future, however, there is limited analyses at the national level to evaluate the current state of road transport emissions and projected changes into the future in individual African countries.

Mutheu Mbandi et al. set out to derive the first ‘bottom-up’ Kenyan transport emission inventory for emissions of both air pollutants and greenhouse gases (GHGs). The authors take it a step further by evaluating mitigation scenarios assessing the emission reductions associated with i) improved vehicle emission and fuel economy standards ii) improved public transport system, and iii) fuel share shift to more renewable energy sources. The study has shown:

• Emissions in the ‘Business as usual’ (BAU) model, were projected to increase 9-fold for NOX, 11-fold for CO2, 31-fold for Non-Methane Volatile Organic Compounds (NMVOC), 19-fold for Particulate Matter (PM), 11-fold for BC, and 28-fold for OC in 2050. 
• Projected increase in bodaboda (motorcycle) ownership will result in a large increase in estimated emissions, and therefore motorcycles should be considered as part of any mitigation strategy for Kenya.
• Combining better fuel economy with improved emissions standards was the most effective reduction scenario for almost all pollutants.

These results suggest that the comprehensive implementation of improvements in fuel economy and vehicle standards, and are also specific to bodaboda use in Kenya and policies that enforce these changes will be beneficial for improving air quality and reducing Kenya’s contribution to short and long-term climate warming.

Dr. Mutheu Mbandi is a part of the International Global Atmospheric Chemistry (IGAC) Global Research Network of Future Earth. She has done research in hazardous chemicals, climate change, mobility and air pollution and is focused on supporting evidence-based air quality management policies. Dr. Mutheu Mbandi is a Lecturer at the South Eastern Kenya University, Kenya and the co-founder of AfriSTEM Connection, a company working to increase STEM and sustainability awareness using emerging technologies in underserved communities in Africa. 

Mutheu Mbandi A., Malley CS., Schwela D., Vallack H., Emberson L., and Ashmore MR. (2023). Assessment of the impact of road transport policies on air pollution and greenhouse gas emissions in Kenya. Enerygy Strategy Reviews 49: 101120. 

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