Monitoring pollution impact on architectural surfaces in terms of colour changing.

The available scenarios of multi-pollutants trends in Europe indicate a shift in modern urban atmospheres from and SO2 dominated situation to a multi-pollutant situation, linked to the driven role played by traffic in determining the overall pollution in urban centres. In view of the proven overwhelming influence of mobile combustion sources in determining the future urban atmosphere, “modern’’ soiling on built heritage will be likely to contain primarily organic carbon (OC). This will imply a change in composition of damage layers, which will presumably assume a yellow-brown colouration. The EC TeACH project (Technologies and tools to prioritize assessment and diagnosis of air pollution impact on immovable and movable cultural heritage) sets out to understand the different types of damage on cultural heritage that can be expected in the future, due to changes in pollutants, both in terms of typology and concentration. Results achieved within this still running project on the composition of damage layers, collected and analysed from different monuments in Europe, will be presented and discussed. Elaboration of carbon fractions data will be liked in particular to colourimetric parameters (L*, a*, b*), with the aim of exploring the application of monitoring of colour change of architectural surfaces as potential strategy for preventive conservation.