The State of Global Air is a research and outreach initiative to provide accurate, meaningful, and the latest information about air quality and its health impacts around the world. A collaboration of the Health Effects Institute and the Institute for Health Metrics and Evaluation’s Global Burden of Disease project, the program gives citizens, journalists, policymakers, and scientists access to high-quality, objective information about air pollution and its health impacts. All data, tools, and reports are free and available to the public. Now in its fifth iteration, the State of Global Air 2024 report presents information on exposures to and health impacts of exposure to common air pollutants including fine particulate matter, ozone, and for the first time, nitrogen dioxide, from 1990–2021. The report draws upon the best available air quality data, estimates of health risks, and demographic data to produce globally comparable country-level data. The SoGA initiative provides a comprehensive resource that complements other sources of information on air pollution and health. This report is produced in partnership with UNICEF and includes a focus on children’s health.