With significant relevance to the Covid-19 pandemic, this paper contributes to emerging ‘aerographic’ research on the socio-materialities of air and breath, based on an in-depth empirical study of three hospital-based lung infection clinics treating people with cystic fibrosis. We begin by outlining the changing place of atmosphere in hospital design from the pre-antibiotic period and into the present. We then turn to the first of three aerographic themes where air becomes a matter of grasping and visualising otherwise invisible airborne infections. This includes imagining patients located within bodily spheres or ‘cloud bodies’, conceptually anchored in Irigaray’s thoughts on the ‘forgetting of the air’ and Sloterdijk’s immunitary ‘spherology’ of the body. Our second theme explores the material politics of air, air conditioning, window design, and the way competing ‘air regimes’ come into conflict with each other at the interface of buildings, bodies and the biotic. Our final theme attends to the ‘cost of air’, the aero-economic problem of atmospheric scarcity within modern high-rise, deep-density healthcare architectures.