In Latin America, ambient air pollution is the leading environmental health risk. Ambient outdoor air quality and residential indoor air quality are linked because, while sources of indoor and outdoor air pollution differ, ambient air pollution affects indoor residential air quality. Outdoor air pollution, particularly fine particulate matter, permeates residential dwellings to become indoor air pollution, lowering residential air quality. This link between ambient air quality and residential air quality implies that improvements in ambient air quality would also lead to improvements in residential indoor air quality. Increasing awareness of the link between ambient air quality and residential air quality could increase citizens’ support for public solutions to ambient air pollution, which would reduce air pollution exposure in both the public and private spheres.