We hear a lot about reducing air pollution, but why do we need to? Join Amy, Naomi and Karl exploring the ins and outs of air pollution including, how the particles affect the human body, and where they come from. We turn to new research that uses machine learning, satellite data and on-the-ground monitors to build a highly detailed pollution map of Great Britain, revealing exciting avenues for the future of air pollution and health research. Contributions from LSHTM's Prof Paul Wilkinson and Prof Antonio Gasparrini.