Vertical Greening Systems (VGS): Integrated technologies for sustainable urban climate mitigation

The present research investigates Vertical Greening Systems (VGS) as integrated nature-based solutions for sustainable urban climate adaptation, with a specific focus on their potential to mitigate specific climate change outcomes, including air pollution, the urban heat island effect, and carbon emissions, challenges central to the 2050 global environmental targets. Framed around the question of how VGS can be effectively designed and implemented to deliver measurable improvements in air quality, the thesis explores the role of plant species selection, the most relevant traits to particulate matter retention (PM1, PM2.5, and PM10), and the technological variables necessary to define performance-based VGS classification. The work is articulated into four main parts: 1) Instructive-analytical: it provides a critical examination of VGS in architecture, their possibilities, typologies, the classification models developed over the past two decades, and their environmental contribution and performance. 2) Evaluative-interpretative: it is built around the exploration of the technological landscape through a market analysis of commercial products, which led to the definition of a new VGS classification model and the outline of six key variables that form the basis for the formulation of a Multi-Criteria Decision Analysis (MCDA) tool. 3) Experimental: it comprises three empirical investigations: two focused on PM retention capacities of selected native and ornamental species using a Scanning Electron Microscope and the automated image analysis with ImageJ software, and a third assessing the thermal and microclimatic performance of a real building envelope equipped with the patented VP-MODULE Living Wall System (LWS) provided by the Verde Profilo enterprise. 4) Synthetic-propositive: applies the MCDA framework to assess the VGS solutions in a real-world case study, enabling comparative evaluation, identifying design constraints, and supporting informed decision-making. This Doctoral research advances the field of architectural technology by transforming experimental evidence into practical tools to guide climate-resilient VGS design. First, the integration of an extensive literature review and direct experiments conducted within this work lays the foundation for a plant species reference framework offering indicators for assessing the PM retention potential capacity of different plant species. Second, the monitored thermal behavior of an LWS installed on a standard building envelope enables the measurement of the impact of vegetation on passive energy performance. Third, the MCDA-based decision-support tool offers a replicable method for evaluating and comparing VGS in context-specific applications, promoting their systematic adoption as scalable, data-driven design strategies for sustainable urban integrated design and climate mitigation.