Air pollution has been linked to various health problems in children, including respiratory and neurological issues. Existing research has also found that exposure to air pollution can affect children's cognitive ability and academic performance, with some studies showing a decrease in test scores and grade point averages associated with increased exposure to hazardous air pollution. This study examined the association between air pollution and children's academic performance in Chile. This research addressed a critical gap in the literature by providing data from an understudied context and tracking children's academic performance at an individual level over time. We constructed a panel dataset that followed students from 1st to 8th grade and estimated their exposure to PM2.5, based on the distance of their school to air monitoring stations from elementary to middle school. We tracked students' academic performance using a longitudinal fixed-effects regression model to assess the relationship between their grade point average (GPA) and air pollution. The results revealed that, on average, an increase in the percentage of days exceeding different official air quality standards significantly affected students' annual GPA. The study also showed that academic performance among students from families with lower economic resources is disproportionately affected by air pollution. The findings underscore the pressing issue of environmental justice, highlighting that numerous students attend schools in the unhealthy environments of several Chilean cities that frequently bear the burden of socioeconomic disadvantage.