This document discusses the health and economic impacts of air pollution. It finds that air pollution poses significant threats to both human health and economic prosperity worldwide. Exposure to ambient (outdoor) air pollution and household air pollution from cooking with solid fuels causes millions of premature deaths annually. The economic costs of air pollution are also substantial, resulting in the loss of trillions of dollars worldwide each year in reduced economic output and welfare. While some regions have made progress in reducing indoor air pollution, ambient air pollution exposure continues to increase in many areas as economies develop. Stronger action is needed to address both indoor and outdoor air pollution to improve health outcomes and drive sustainable economic growth.