Exposure assessment of air pollution in epidemiologic research remains a challenge. Previous studies showed that magnetic monitoring of strawberry leaves, based on Saturation Isothermal Remnant Magnetization (SIRM), is a valid tool for estimating the concentration of ambient particulate matter (PM). This study uses this assessment method for the first time in epidemiologic research to quantify indoor exposure to PM. In a nested case control study, we evaluated the association between ‘waking up by cough’ and indoor air pollution measured by SIRM of dust deposition on leaves of strawberry plants located in the bedroom in the general adult population. A multiple logistic regression was used to estimate the association between ‘waking up by cough’ and exposure to ferromagnetic particles of PM controlling for age, gender and smoking status. A cut-off of 10 µA was decided to define exposure status (high versus low). Using logistic regression, a crude odds ratio (OR) of 1.80 (95% CI: 0.90–3.60) for ‘waking up by cough’ was found. This association remained approximately the same after controlling for age, gender and smoking status (adjusted OR: 1.76; 95% CI: 0.60–5.30). We found an association between exposure to ferromagnetic particles and ‘waking up by cough’ in adults; however, it was not statistically significant. This environmental exposure assessment method could be a valuable alternative for expensive personal exposure measurement devices.

This study examines the particulate matter (PM) capture capacity of living wall systems (LWSs), focusing on leaf traits that facilitate PM deposition. Six LWS designs, differing in structure and substrate, were tested under constant airflow conditions with and without additional PM. Results showed that planter-based LWSs reduced PM_0.1 by 2% and PM_2.5 by 4%, while a textile LWS reduced PM_0.1 by 23% and PM_2.5 by 5%, though geotextile textile increased PM by 11% for both fractions. A moss substrate LWS worsened air quality, raising PM_0.1 by 2% and PM_2.5 by 5%. Magnetic analysis of leaf-deposited PM (SIRM) revealed species-specific differences (p < 0.001), with SIRM values ranging from 5 ± 1 µA to 260 ± 1 µA and higher PM accumulation in plants with lower specific leaf areas. No differences were observed in SIRM between deposition and resuspension phases, indicating the PM source lacked sufficient magnetisable particles. The findings highlight the potential of LWSs in urban environments for air quality improvement but underscore the importance of selecting suitable LWS structures and plant species.

As cities continue to grow and densify, urban environments face mounting challenges related to air pollution and rising temperatures. While trees and green roofs have long been recognized for their environmental benefits, vertical green infrastructure (VGI) remains underexplored. This doctoral research investigates the potential of VGI to mitigate two critical urban issues: particulate matter (PM) air pollution and the urban heat island (UHI) effect.​​ The thesis combines common garden experiments, wind tunnel studies, and literature reviews to assess how different plant species and system configurations influence the environmental performance of green walls. A first objective was to characterize the aerodynamic behavior of vegetation in green walls. Using wind tunnel experiments and computational fluid dynamics (CFD) modeling, the study demonstrates how specific leaf traits — such as specific leaf area (SLA), leaf dissection index (LDI), and functional leaf size (FLS) — affect airflow resistance and pollutant dispersion. The research quantifies the PM capture capacity of various living wall system types. Both lab experiments and outdoor monitoring reveal that plant species with lower SLA values tend to accumulate more PM, and that system design significantly influences deposition and resuspension dynamics of PM. The thesis also evaluates the cooling potential of green walls in a temperate climate. Field measurements show that green walls can reduce surface and air temperatures through shading and evapotranspiration, with performance varying with plant type and irrigation regime. Notably, even under drought stress, living wall systems maintained a measurable cooling effect, highlighting their resilience in changing climate conditions.​​ This thesis translates its findings into practical recommendations for urban planners and policymakers. It identifies key design parameters for maximizing environmental benefits of VGS, while also acknowledging limitations in present knowledge such as the need for irrigation, lack of biological replicates in literature, and the underrepresentation of certain traits like leaf hairiness. By bridging plant science, environmental engineering, and urban design, this research contributes to a better understanding of how vertical greening can be strategically implemented to create healthier, more climate-resilient cities.