449 Carpathian Journal of Earth and Environmental Sciences, August 2016, Vol. 11, No 2, p. 449 - 462 DETERIORATION OF GLAZED ARCHITECTURAL CERAMICS DUE TO ENVIRONMENTAL FACTORS: A COMPARATIVE STUDY OF TWO BUILDINGS IN BUDAPEST Ágnes BARICZA 1 , Bernadett BAJNÓCZI 2* , Máté SZABÓ 2 , Mária TÓTH 2 , Zsolt BENDŐ 3 & Csaba SZABÓ 1 1 Lithosphere Fluid Research Lab, Department of Petrology and Geochemistry, Institute of Geography & Earth Sciences, Eötvös Loránd University, H-1117 Budapest, Pázmány Péter sétány 1/C, Hungary, baricza.agnes@gmail.com, cszabo@elte.hu 2 Institute for Geological and Geochemical Research, Research Centre for Astronomy and Earth Sciences, Hungarian Academy of Sciences, H-1112 Budapest, Budaörsi u. 45, Hungary, bajnoczi.bernadett@csfk.mta.hu, *corresponding author toth.maria@csfk.mta.hu, szabo.mate@csfk.mta.hu, 3 Department of Petrology and Geochemistry, Institute of Geography & Earth Sciences, Eötvös Loránd University, H- 1117 Budapest, Pázmány Péter sétány 1/C, Hungary, zsolt.bendo@gmail.com Abstract: The Zsolnay products are one of the most famous Hungarian ceramics. The architectural ceramics produced by the Zsolnay Factory were often applied to decorate buildings, mainly around the turn of the 19 th and 20 th centuries. We have studied two buildings in Budapest, the Museum of Applied Arts in the densely built-up centre of the city with high traffic rate, and the Geological and Geophysical Institute of Hungary in a city quarter with moderate traffic and more open space. The main aim was to study the effects of the environmental factors (e.g. rainfall, gaseous pollutants in air, living forms) and the deterioration phenomena on the glazed roof tiles of the buildings. Two types of Zsolnay ceramics were examined: one from the building period and another one from the 20 th century renovation periods of the buildings. The objects are similar in their ceramic bodies, but different regarding the covering glaze layers. Black deposition, traces of biological activity, and natural and artificial particles were identified on the ceramics of both buildings. A distinctive difference was the presence of gypsum frequently covering the objects of the Museum of Applied Arts. On some objects of this building pitting corrosion and weathering of the glaze were observed and lead was leached from the thin surface layer of the glaze as well as along cracks-microcracks in the glaze, in addition lead-rich depositions were precipitated. If weathering continues for a long period, it will result in the deterioration of the whole glaze. Keywords: architectural ceramic, glaze, Zsolnay, deterioration, environmental factors, Budapest 1. INTRODUCTION In the last decades much more attention is being paid to the influence of mankind on our environment than previously. All types of the building materials are continuously exposed to the environmental harmful factors (e.g. rainfall, gaseous pollutants in air, living forms) originating from physical, chemical or biological sources. Some decades ago the deterioration of building materials were slower, however, nowadays the rate of the deterioration is faster mainly in urban areas and densely populated cities (Grossi & Brimblecombe, 2007). In the 21 st century one of the major roles of society is to conserve the historical and cultural heritage. These days it is well known how the environmental factors, like high traffic rate or gaseous pollutants, launch deterioration on natural building materials, e.g. carbonate rocks (limestone, marble), sandstones or volcanic rocks (e.g. Ausset et al., 1999; Török et al., 2011; Maravelaki-Kalaitzaki, 2005; Garcia-Vallés et al., 1998; McCabe et al., 2011; Monte, 2003). It is widely accepted that “the high melting temperatures of ceramics and glasses implies that diffusion coefficients of most of the elements are too