This chapter develops the concept of breathing intimacy to examine how respiratory practice constitutes an enforced relationality between bodies and anthropogenic atmospheres. Taking as its departure point the contested recognition of the Anthropocene as a formal geological epoch, the chapter argues that the most immediate traces of this epoch are not only deposited in sedimentary strata but actively metabolized through breathing bodies—making flesh an archive of planetary transformation that geological evidence alone cannot capture. Drawing on critical respiratory studies, feminist political ecology, and more-than-human scholarship, breathing intimacy is theorized across three coconstitutive dimensions: the more-than-human entanglements forged through respiratory oscillation, the worlding and commoning practices through which such entanglements extend beyond individual bodies, and the epistemological tension between atmospheric governance metrics and the embodied knowledge that breathing bodies accumulate. These dimensions are traced through two empirical cases—asbestos exposure in Hong Kong’s rooftop subdivided housing and transboundary haze across the Mekong subregion in Southeast Asia—which demonstrate how structurally marginalized bodies are drawn into deep, sticky, and unwilled intimacy with atmospheres saturated by capitalist extraction. The chapter concludes by calling for denationalized respiratory collectives that move beyond urban- or nation-centric frameworks, confronting atmospheric inequality through the shared vulnerability that breath, inescapably, enforces.