The Belle Époque: a cultural history, Paris and beyond

some fled London to the country, mirroring a change described by Defoe (1722) during the plague of 1665. It may be that these émigrés will never return. London is still polluted, but not by coal smoke, and more recent times have seen the city troubled by nitrogen rich fogs in winter and photochemical smog in summer. While many pollutants are at lowered concentrations, London still struggles to meet the World Health Organization guidelines. Scientists examining environmental change have increasingly turned to the historical record. In recent years there has been a flurry of studies, for example, on the impact of historical pollutants on the changing rate of damage to building façades in cities. The rate of damage has decreased as the levels of smoke and sulfur dioxide in the air have declined (Brimblecombe and Grossi 2009; Grøntoft, 2021; Ionescu et al. 2012). Such studies remind us that our interest in long term change in the environment benefits from an understanding of history and the importance of historical materials as a source of data. History seems more important than ever, but also leaves us with a sense of the legacy that the early reformers in London created; they did not solve the air pollution problem, so much as ensure that we saw it as a problem to be solved.