This project studies the impact of air pollution on primary school students’ cognitive performance in Italy. Using longitudinal INVALSI data matched with high-resolution PM2.5 measures, it exploits day-to-day variation in exposure to identify causal effects. Results show that pollution on exam days lowers performance, especially in reasoning intensive tasks and among more vulnerable students. The findings highlight both the cognitive costs of pollution and the mitigating role of interventions such as air filtration.