This paper investigates the use of a citizen science approach for air quality monitoring to explore the likely pollution impacts of the new Missing Link #12 road passing through the informal settlement of Kibera, within Nairobi. Citizen science approaches are gaining relevance in air quality monitoring thanks to the advancement in environmental monitoring technology and the opportunities created for community-based organizations to collect data on air pollution through low-cost sensors. Fourteen households located in proximity to the Missing Link#12 were equipped with optical particle sensors. Data collected indicated that people living along the road are exposed to levels of PM2.5 and PM10 above WHO recommendations, mainly due to the particulate generated by the construction site and fuels used for indoor cooking. A community engagement workshop revealed that participatory approaches are useful for improving awareness of air pollution and associated health implications. It also allowed the community to enhance their capability to gain and use scientific tools to address local issues, and potentially lobby decision-makers to solve them. In the context of transport infrastructure development in African cities, such an approach can be a means of collecting data and monitoring the impacts of air pollution during and after road building.