This paper examines the long-term impacts of early childhood exposure to air pollution on adult outcomes using U.S. administrative data. We exploit changes in air pollution driven by the 1970 Clean Air Act to analyze the difference in outcomes between cohorts born in counties before and after large improvements in air pollution relative to those same cohorts born in counties that had no improvements. We find a significant relationship between pollution exposure in the year of birth and later life outcomes. A higher pollution level in the year of birth is associated with lower labor force participation and lower earnings at age 30.