Use of advanced analytical techniques for air monitoring and investigation of archaeological biomarkers within the context of Cultural Heritage

The research project described in the present PhD thesis involves a multidisciplinary study for the integrated diagnostics and monitoring of the conservation state of archeological materials, and the environmental quality of sites of historical and artistic interest, through low-cost smart sensors, analytical surveys and statistical analysis. The first step of the project was the selection of the “Accascina” Messina Regional Interdisciplinary Museum (MuMe) as an ideal location for monitoring indoor and outdoor air quality and understanding the ageing phenomena of materials of historical-artistic interest (stone, pictorial, archaeological materials). MuMe is housed in a former late 19th-century spinning mill (Mellinghoff spinning mill) and in the adjacent former Basilian monastery of San Salvatore dei Greci. The first was adapted for temporary exhibitions purposes, while the second is designated for the permanent exhibition. An extensive series of interventions to create the new exhibition space has resulted in the present layout of the areas and design of the exhibition pathway. The museum exhibits figurative art from Messina spanning the 12th to the 18th centuries, including paintings, sculptures, archaeological finds, artworks, and decorative artifacts. The collections are arranged chronologically and include works by prestigious authors such as Antonello, Caravaggio, Laurana, with different colors to represent the different artistic eras. The museum is located in a coastal area of the city, linking the urban center to the northern outskirts. While its proximity to the sea and the port offers significant advantages, such as a picturesque setting and a strong connection to the city's maritime heritage, it also presents challenges. These include exposure to saltwater and pollution from maritime transport in the Strait of Messina. Additionally, the presence of an airport on the opposite side of the Strait of Messina (Reggio Calabria airport), which could further impact the air quality in the area, needs to be considered. For these reasons, the present research study aimed to evaluate and compare the air quality inside and outside the MuMe, in order to provide valuable insights into the environmental conditions impacting the museum. The monitoring was carried out primarily by collecting real-time data on critical parameters such as temperature, humidity, particulate matter, and gas concentrations using low-cost advanced sensor technologies, developed in collaboration with the university spin-off SmartME.IO S.r.l (Case Study 1). Specifically, sensors were installed at strategic locations both inside and outside the museum to measure meteorological parameters, including temperature, wind direction and speed, relative humidity, atmospheric pressure, solar radiation, and rainfall. Additionally, the concentration of atmospheric pollutants indoors and outdoors was monitored, including particulate matter (PM10, PM2.5, and PM1) and gaseous pollutants like carbon dioxide (CO2), nitrogen dioxide (NO2), sulfur dioxide (SO2), and ozone (O3). In addition, since the museum is located in an urban center, surrounded by a complex and changeable urban environment, particulate matter poses a significant risk to Cultural Heritage, being not only an aesthetic issue but also an agent of chemical degradation. The threat posed by the exposure of museum artifacts to particulate matter is not only related to the quantity of particles but also to their chemical composition, which includes inorganic components such as metals, sulphates, and nitrates, soil dust, and organic compounds such as polycyclic aromatic hydrocarbons (PAHs), biological materials, including complex mixtures of elemental carbon and organic carbon. Chemical analyses of aerosols and PM samples are therefore necessary to identify the primary sources of particulate matter. For instance, for the detection and quantification of PAHs, one of the most powerful analytical techniques is represented by gas chromatography coupled with mass spectrometry (GC-MS), due to its high selectivity, sensitivity, and its ability to accurately identify and quantify trace levels of PAHs in complex environments. In this context, during an internship period at the Institute of Chemical and Environmental Engineering of the University of the Bundeswehr (UniBW, Munich, Germany), the research was focused on the optimization of an advanced gas chromatography-tandem mass spectrometry (GC-MS/MS) method for the characterization of PAHs in PM (Case Study 2). In particular, the research work drawn upon established protocols from the literature, with the aim of enhancing their overall efficiency, analytical precision, and sustainability. MuMe’s collection includes also highly valuable archaeological artifacts on display. Through the extraction and analysis of organic residues from archaeological ceramics, answers to a variety of archaeological questions about ancient societies, including those related to diet, food storage and processing, rituals and medical practices, trade and the use of commodities, and animal domestication, etc., can be provided. This approach plays a key role in uncovering important insights into the daily lives of past civilizations. In this context, the research project also focused on the analysis of organic residues in archaeological pottery using various analytical techniques. Specifically, lipid compounds were examined, as they are considered ideal candidates as "archaeological biomarkers". Lipid contents from twenty-four archaeological samples, excavated from the Roman domus of Villa San Pancrazio in Taormina, Italy (Case Study 3), and twenty-two samples from the Bobinac-Kozerina Cave in Lika (Croatia) (Case Study 4), were determined. Prior to this, the project first focused on ageing studies performed on olive oil (Case Study 3), aiming to identify potential archaeological biomarkers for olive oil. Up until now, in fact, there was no clear information on biomarkers that may identify the presence of olive oil, a staple of ancient Mediterranean societies' lifestyles, in organic residues. Performing artificial ageing studies may provide key elements to better interpret the origin of plant oils and animal fats that are partially or totally altered over time, through the understanding of chemical and biochemical mechanisms responsible for their alteration, thus helping to discover potential archaeological biomarkers.