The cleanliness, mobility and quality of urban air has become prominent again in debates on post-pandemic cities. To contextualize the political and epistemological significance of air in urban contexts, this article presents a longue durée history of the complex ecological solutions of premodern cities and towns, guided by findings from Hippocratic-Galenic medicine. While we do not romanticize these solutions, we argue that they represent an under-researched archive through which questioning the post-Enlightenment mechanization, securitization and abstraction of air. Turning to recent findings from microbiology and building science to reflect on how air has once again gained political legibility in post-Covid debates, we argue that both the prehistory we show and contemporary findings from laboratory science about the aerobiome point to a re-enchantment of the air as something that cannot be instrumentalized or securitized as in modernistic programs of biopolitical control. We suggest instead to re-frame human-air relations drawing on more-than-human thinking, to arrive at an affirmative reconceptualization of human-environment entanglement based on notions of permeability and a non-binary ontology of flows.