This report summarizes the latest scientific knowledge on the links between exposure to air pollution and adverse health effects in children. It is intended to inform and motivate individual and collective action by health care professionals to prevent damage to children’s health from exposure to air pollution. Air pollution is a major environmental health threat. Exposure to fine particles in both the ambient environment and in the household causes about seven million premature deaths each year. Ambient air pollution (AAP) alone imposes enormous costs on the global economy, amounting to more than US$ 5 trillion in total welfare losses in 2013.