## 2 Pompeii Sustainable Preservation Project. Purpose and Research Activities  
The Pompeii Sustainable Preservation Project (PSPP) is an international project entirely based on fundraising and direct financing by private investors, which, operating within the extraordinary context of the necropolis of Porta Nocera in Pompeii, aims to research and experiment with methodologies, techniques and materials for the conservation and restoration of ancient monuments, combining research, heritage conservation and education [4; 5]. Indeed, research activity is only one of the aims of the PSPP, as it is intended as a preliminary step to restoration and conservation works, conducted directly in the field by experts from different disciplines in collaboration with young restorers involved in the project through an annual summer school. The evaluation of the results achieved increases the initial knowledge base, which is made available for further conservation work in the future. Building on the successful experience of the Herculaneum Conservation Project [6; 7; 8], the PSPP operates through an international consortium of public and private institutions under the scientific coordination of the archaeological park of Pompeii, together with the Fraunhofer-Institut fur Bauphysik (IBP), which conceived and directed the project and operate the Technische Universitat Munchen (TUM), the International Centre for the Study of the Preservation and Restoration of Cultural Property (ICCROM) and a group of researchers from the ex-Institute for Archaeological and Monumental Heritage of the National Research Council (IBAM-CNR), now part of the Institute of Sciences for Cultural Heritage (ISPC-CNR), Catania branch. In addition, these institutions support the PSPP with individual research projects: The School of Geography and Environment of the University of Oxford; the High Institute for Conservation and Restoration of the Italian Ministry of Culture (ISCR), the Department of Ancient History, Ludwig-Maximilians-Universitat of Munich (Lmu Munchen), the Deutsches Archabologisches Institut of Rome (Dai) and the University of Pisa. The Pompeii Sustainable Preservation Project began in 2014 and carries out its activities within the extraordinary context of the necropolis of Porta Nocera and the adjacent Via Nucerina with annual programs that alternate between the three fundamental stages of research, restoration and learning (Figure 1). Thanks to the activities carried out until now, it has been possible to obtain an accurate overview of the state of conservation of the funerary monuments within the specific context of the investigation and to identify any causes of degradation in progress. This required an extensive campaign of surveys, necessary to obtain a reference base that would provide a reliable representation of the spatial location, dimensions and volume of each funerary building. Additional geophysical, chemical and microclimatic investigations allowed us to collect information about the environmental components of the context, useful for identifying the causes of possible structural deterioration. Finally, each funerary building was subjected to a process of analysis to define its technical and construction characteristics, the materials used and the main signs of deterioration. The acquired knowledge made it possible to isolate multiple causes of degradation of abiogenic and environmental nature that affect the future conservation of the monuments. Among these, for instance, particularly serious were the effects on the foundation structurescaused by the presence of groundwater, which was facilitated by the position of the two sectors of the necropolis of Porta Nocera and Via Nucerina, located in one of the lowest points of the entire archaeological area. In this way, it was possible to arrive at an overall view of the current level of conservation of the structures, while, at the same time, a process of monitoring the evolution of the main components of the environmental framework overtime was initiated.