Exposure to Lead of Some Affects Everyone in the Classroom

Children exposed to pollutants like lead are more disruptive and have lower achievement. However, little is known about whether lead-exposed children affect the long-run outcomes of their peers. 

This study estimates these spillover effects using new data on preschool blood lead levels (BLLs) matched to education data for all students in North Carolina public schools. The study compares siblings whose school-grade cohorts differ in the proportion of children with elevated BLLs, holding constant school and peers’ demographics. 

Having more lead-exposed peers is associated with lower high-school graduation and SAT-taking rates and increased suspensions and absences. Peer effects are larger for same-gendered students.