Long-term damage to glass in Paris in a changing environment Anda Ionescu a, ⁎, Roger-Alexandre Lefèvre a , Peter Brimblecombe b , Carlota M. Grossi b a Université Paris-Est Créteil, 61 Avenue du Général de Gaulle, 94010 Créteil Cedex, France b School of Environmental Sciences, University of East Anglia, Norwich NR4 7TJ, UK abstract article info Article history: Received 28 February 2012 Received in revised form 27 April 2012 Accepted 9 May 2012 Available online xxxx Keywords: Modern glass Stained glass windows Climate change Air pollution Dose–response functions Glass weathering depends mainly on its chemical composition: Si–Ca–K mediaeval glass is low durable, while Si–Ca–Na Roman as well as modern glass are very durable. Mediaeval glass is subject to the superficial leaching of K and Ca ions leading to the formation of a hydrated silica-gel layer. Both types of glass develop a superficial stratum of deposited atmospheric particles cemented by crystals of gypsum (and syngenite in the case of Si–Ca–K glass), leading to an impairment of the optical properties: decrease of transparency and increase of haze. Dose–response functions established for the two types of glass reveal that haze depends only on pollution parameters (PM, SO 2 , NO 2 ), while leaching depends both on pollution and climate param- eters (RH, T, SO 2 , NO 2 ). Instrumental records are available for temperature in Paris from 1800. Air pollution in Paris was estimated from statistics of fuel use from 1875 to 1943, measurements that started in the 1950s and projections across the 21st century. The estimated annual rate of haze development indicates a gradual rise from the 16th century. The increasing importance of coal as a fuel through the 19th century and enhanced sulphur dioxide concentration make a rapid increase in haze formation, which reaches a peak about 1950. The likely damage to mediaeval glass follows a rather similar pattern. The period of damage from aggressive pollutants looks later and for a briefer time in Paris than in London. © 2012 Elsevier B.V. All rights reserved. 1. Introduction Glass is a durable material that has been increasingly used as a building material over time. Despite its early manufacture in Ancient Rome and in Egypt it was not widely used for windows until mediae- val times. The manufacture of crown glass for windows was a speci- ality of French glass-makers in the early 1300s. The long history of glass in France makes it worthwhile to develop a long-term history of its degradation. This follows an approach adopted in outlining the long-term evolution during one millennium in London used pre- viously for the recession of limestone façades (Brimblecombe and Grossi, 2008) and later for metals and the soiling of stone surfaces (Brimblecombe and Grossi, 2009). A study predicting 21st century recession of architectural limestone in European cities including Paris has been also achieved (Grossi et al., 2008). This work addition- ally used output from climate models and estimates of future pollut- ant concentrations to extend predictions of the rate of damage to the end of the current century. This paper is an attempt to extend these results to Paris and to glass (where used both in windows and as historic stained glass) as glass was not discussed in any depth during the earlier studies on stone and metals in London or elsewhere in Europe. The extension to future climate is able to use output from the HadCM3a2 model and changes in emission to aid an understanding of the likely evolu- tion of corrosive air pollutants in Paris. The impacts of climate change on the scale of Paris were pre- viously studied in the EPICEA Project funded by the City of Paris (Colombert, 2008; Desplat et al., 2009). The goal was to search a link between the urban built environment and the urban climate. The results confirm the importance of radiative characteristics of ma- terial surfaces on the global energy balance. Nevertheless the glass of windows was only taken into account for its thermal properties and the impact of air pollution on materials only in general and theoreti- cal terms for the decrease of albedo. 2. Glass, a material more or less “weatherable” Glass as a human product is very ancient – more than 4000 years old – and its chemical composition widely varied with time according to the sources of its components. In the Roman times, when natron (natural NaCO 3 ) and lime–silica sand (CaCO 3 + SiO 2 ) were available in the Eastern Mediterranean and in the Italian peninsula, they were used as raw materials. From the 8th century and during the mediae- val times they were progressively replaced by a siliceous sand (SiO 2 ) and vegetable ashes obtained from the combustion of conti- nental plants in Northern Europe and from coastal plants in the Med- iterranean area. Depending on the nature of the ash, potash–lime– silica obtained from continental plants or soda–lime–silica from coastal plants were melted. In the modern times, industrial soda Science of the Total Environment 431 (2012) 151–156 ⁎ Corresponding author. Tel.: +33 1 45 17 18 46; fax: +33 1 45 17 65 51. E-mail addresses: ionescu@u-pec.fr (A. Ionescu), lefevre@lisa.u-pec.fr (R.-A. Lefèvre), p.brimblecombe@uea.ac.uk (P. Brimblecombe), c.grossi-sampedro@uea.ac.uk (C.M. Grossi). 0048-9697/$ – see front matter © 2012 Elsevier B.V. All rights reserved. doi:10.1016/j.scitotenv.2012.05.028 Contents lists available at SciVerse ScienceDirect Science of the Total Environment journal homepage: www.elsevier.com/locate/scitotenv