Impacts of Contemporaneous Air Pollution Exposure on Cognitive Performance in Kenya

We estimate the short-term cognitive effects of fine particulate matter (PM2.5) exposure using highly time-resolved, individual-level data collected during cognitive testing in Kenya. By linking real-time portable monitor readings to Harmonized Cognitive Assessment Protocol (HCAP) scores, we identify acute impacts of pollution on general and domain-specific cognition. Higher PM2.5 exposure during testing is associated with lower cognitive performance, particularly in memory, executive function, and visuospatial tasks. Nonlinear models suggest threshold effects, with larger declines at higher exposure levels. Notably, effects are significantly larger among more educated individuals, possibly due to greater task demands or lower chronic exposure that limits physiological adaptation. Given that cognitive impairment is evident even at PM2.5 levels below Kenya’s annual regulatory threshold of 35 μg/m³, the findings suggest that short-term exposure may impose underappreciated human capital costs that current regulatory standards fail to mitigate. The results highlight the potential cognitive and economic returns to interventions that reduce air pollution exposures in low-resource settings.