Quantification of short-lived climate pollutant (SLCP) reductions from soot-free bus strategies in Kenya’s capital city of Nairobi

Quantification of environmental pollutants is critical towards building city strategies in air quality as well as mitigation benefits attribution. Moreover, it is directly related to national strategies on climate change and global warming mitigation including climate change planning process and nationally determined contribution. This information is however lacking hence a major hindrance to discussion and debates around clean air in Kenya’s capital city, Nairobi.

This report presents modelled quantitative information on short lived climate pollutants - SLCPs (PM2.5, black carbon, methane and organic carbon) in the road transport sector in Nairobi metropolitan. Two scenarios - county plan scenario and soot-free vehicles scenario - were developed to assess mitigation benefits in a 2040 trajectory against the reference (business-asusual). The business-as-usual (BAU) scenario assumed current trends of transport system and fuel quality, county plan scenario adopting strategies articulated in National Climate Change Action Plan 2018 – 2022 and the ambitious soot-free bus scenario seeking to replace small capacity public service vehicles (matatus and mini-buses) with buses and eventually transition to 100% electric bus rapid transit (BRT).

The model results showed that, in the BAU, SLCP emissions in the base year (2019) was: PM2.5, – 470 tons, Black Carbon – 250 tons and Organic Carbon – 90 tons which are likely to quadruple by 2040. However, implementing SLCP emission reduction strategies would reduce the emissions by 45% and 96% in county plan scenario and soot-free buses scenario respectively by 2040. It can be concluded that, the ambitious soot-free bus scenario could possibly deliver black carbon and particulate matter free city depending on effectiveness and robustness of county policies and strategies and national collaboration, enhancing human wellbeing, national competitiveness and sustainable economic development. Summarily, key recommendations include building absorptive capacities, learning and knowledge transfer, piloting and deployment of soot-free bus strategies.