ELSEVIER The Science of the Total Environment 171(1995) 363-172 Air pollution loads on historical monuments: an air quality model application to the marble Arch of Titus in Rome M. Chiara Metallo*“, Attilio A. Poli”, Maurizio Dianab, Franca Persiab, Mario C. Cirillob “A.R.LA., V?a Fausti, 40, 00062 Bracciano, Rome, Italy bEhEA, C.R.E. Casaccia, C.P. 2400, 00100 Rome, Italy Received 11 November 1993; revision received 7 July1994; accepted 17 January 1995 Abstract Atmospheric pollution is one of the reasons for stoneweatheringof monumental structures;at the same time old town centresare high concentration areas of pollutant sources (traffic and domestic heating) and of outdoor works of art. The useof air dispersion models represents a short means of answering many questions concerning pollution and it is a complementary way to the traditional ad hoc measurement of pollutant concentrations. An application of DIMULA, an analytical multisource dispersion model, and of CALINE 3, an air dispersion model specially developed for pollutant line sources (road links) will be described. The first wasapplied to the entire urban area of Rome and the second to the surroundings of the Arch of Titus. A simulation was performed relative to the period of in situ monitoring of air pollutant species and meteorologicalconditions. Moreover simulations of the effect of possible actions to reduce pollution around the monument(e.g., traffic limitation, useof different fuels) have been performed. Once the model has been validated, this approach, compared with the traditional approachinvolving a large amount of measurements, has the merits of being reliable and economical. Keywords: Air pollution; Historical monument;Air quality model; Marble 1. Introduction Urban areas are characterized by high levels of pollutant emissions from anthropic activities. Moreover historical centres, especially in Europe, are studded with outdoor works of art thus suf- * Corresponding author. fering not only time and weather injuries but the fateful attack of air pollution too. The negative effects of pollution are various and complex depending on the materials consti- tuting the monuments, on pollutant substances (Arnoroso and Fassina, 1983) and on meteorologi- cal and thermodynamic parameters. For instance the sulphatation reaction resulting in gypsum for- mation is due to sulphur dioxide (SO,) attack on 004%9697/95/$09.50 0 1995 Elsevier Science BV. All rights resewed. SSDZ 0048-9697(95) 04690-3