This paper examines the impact of pollution on worker productivity, focusing on the effects of ozone pollution on agricultural workers. The authors use a unique dataset from a farm in California's Central Valley, where workers are paid through piece-rate contracts, to analyze the relationship between ozone levels and productivity. They find that a 10 parts per billion (ppb) decrease in ozone concentrations increases worker productivity by 5.5%. The study also explores the sensitivity of these results to various assumptions and controls, including the potential for shirking under minimum wage contracts. The findings suggest that environmental protection can be viewed as an investment in human capital, contributing to firm productivity and economic growth. The results have implications for ongoing debates on ozone policy, indicating that strengthening regulations on ozone pollution could yield significant benefits.This paper examines the impact of pollution on worker productivity, focusing on the effects of ozone pollution on agricultural workers. The authors use a unique dataset from a farm in California's Central Valley, where workers are paid through piece-rate contracts, to analyze the relationship between ozone levels and productivity. They find that a 10 parts per billion (ppb) decrease in ozone concentrations increases worker productivity by 5.5%. The study also explores the sensitivity of these results to various assumptions and controls, including the potential for shirking under minimum wage contracts. The findings suggest that environmental protection can be viewed as an investment in human capital, contributing to firm productivity and economic growth. The results have implications for ongoing debates on ozone policy, indicating that strengthening regulations on ozone pollution could yield significant benefits.