This study looks at the air quality consequences of Uber in the United States by estimating its impact with state-of-the-art difference-in-difference estimators accounting for Uber’s staggered implementation and dynamic treatment effects. Results show that Uber improves air quality. The value of the air quality index and the number of unhealthy air quality episodes decrease after its introduction. We provide evidence that the bulk of the improvement comes from declining ozone levels during the summer alongside smaller reductions in traffic-related pollutants. To the best of our knowledge, this is the first study to estimate the air quality consequences of ride-hailing technologies.