Accuracy Meets Affordability: Evaluating the Impacts of Policies on Air Pollution in Low- and Middle-Income Countries

Abstract This paper informs the design of air pollution monitoring systems for PM2.5 measurement and estimation of policy impacts in urban areas of Sub-Saharan Africa. We find low-cost monitors underestimate PM2.5 levels relative to satellite and regulatory-grade data, but context-specific calibration improves alignment. We evaluate the effect of a set of policies implemented citywide on air pollution at the city level using each data source in a difference-in-differences design and find similar results, especially in percent. Using a spatially targeted intervention, we demonstrate the importance of a dense network of air pollution monitors for capturing the effects of policies with high spatial variation in impacts. These results show that policymakers can monitor air pollution concentrations and the impacts of policies on air pollution with higher accuracy and lower cost by colocating one regulatory-grade monitor in a network of low-cost monitors.