Geochemical study of air quality in areas affected by the addition of anthropogenic and natural contaminants

As societies face escalating challenges due to air pollution, this PhD research introduces a novel, integrated approach to air quality assessment, aimed at complementing and enhancing traditional monitoring methods. The approach addresses limitations in current practices, which struggle to keep pace with global demands for mitigation. This need is driven by factors such as (i) the dual role of urban and industrial areas as sources and targets of pollutants; (ii) increased populations living near volcanic-hydrothermal regions with heightened gas exposure risks; (iii) land reclamation that degrade ecosystems like wetlands, accelerating production and emissions of greenhouse gases. The study was developed in two phases: (1) design, development, and testing of innovative multiparametric monitoring stations equipped with low-cost sensors and based on open-source electronic platforms; (2) deployment of these cost-effective stations at fixed monitoring sites, alongside a mobile unit equipped with high-technology instruments, in specific regions impacted by air pollutants from natural and anthropogenic sources. A calibration procedure based on an ensemble machine-learning algorithm was implemented to calibrate the low-cost CO2 and CH4 sensors, offering robust, efficient data processing and broad usability. The algorithm used data from the high-technology analyzers as a calibration reference across diverse environments and seasons to minimize site transferability issues, yielding accurate CO2 and CH4 readings (with mean absolute errors below 4 ppm and 40 ppb, respectively). The second phase demonstrated this integrated strategy’s effectiveness in air quality assessment across areas of interest, including: (i) Vulcano Island (southern Italy) and (ii) Pozzuoli (southern Italy), where residents live with volcanic-hydrothermal emissions; (iii) Padule di Fucecchio (central Italy), a wetland ecosystem subject to intense urban pressure that acts as a degrading factor accelerating CH4 production and release to the atmosphere; (iv) a plant for CO2 exploitation and refining at Sant’Albino (central Italy), where natural and anthropogenic CO2- and H2S-rich emissions occur. Air monitoring at fixed sites revealed temporal trends of CO2, CH4 (at FU), PM2.5, and PM10 within these areas, highlighting critical zones that may benefit from the installation of a dedicated monitoring array. Meanwhile, the mobile unit enabled high-resolution spatial mapping of pollutants, identifying key sources and mechanisms based on isotope chemical data. This research establishes an integrated fixed-mobile monitoring strategy—with low-cost and high-technology instruments—as a scalable, adaptable solution for comprehensive air quality evaluation. The findings underscore its potential to support public health, inform policy, and foster community engagement, setting a foundation for next-generation air quality monitoring networks.