Abstract
This article centres on the unprecedentedly severe fog crisis which afflicted London between the 1870s and the mid-1890s. An overview of meteorological developments prefaces an interrogation of the mid-Victorian origins of environmental cost-benefit analysis and the only slowly dawning awareness that adverse weather conditions might make a significant contribution to mortality and morbidity from respiratory disease. At the same time, exceptionally degraded air quality came to be associated with the threat of physical and psychological degeneration in the poorest inner and eastern districts of the city. Perceived as a totality, these bodies of knowledge and ideology - economic, epidemiological and social Darwinistic - reinforced and legitimated a catastrophist fin de siècle vision of almost unbearably debilitating social, economic and cultural relationships between 'darkness at noon' and the potential implosion of the late nineteenth century metropolis.