Citizens of Worlds is the first thorough study of the increasingly widespread use of digital technologies to monitor and respond to air pollution. Drawing on data from the Citizen Sense research group, Jennifer Gabrys argues that citizen-oriented technologies promise positive change but collide with entrenched and inequitable power structures, and explains how people respond to, care for, and struggle to transform environmental conditions informs the political subjects and collectives they become. Gabrys is chair in media, culture and environment in the Department of Sociology at the University of Cambridge, and the author of books including Digital Rubbish: A Natural History of Electronics.