In the Original Investigation titled “Association of Ozone Exposure With Cardiorespiratory Pathophysiologic Mechanisms in Healthy Adults,” published online July 17, 2017, in JAMA Internal Medicine,1 a sentence was missing from the beginning of the Author Contributions section. The first 2 sentences now read: “Drs Y. Zhang and J. Zhang contributed equally and are considered co–senior authors of this work. In addition, they had full access to all the data in the study and take responsibility for the integrity of the data and accuracy of the data analysis.” This article was corrected online.