Indoor green walls for improving air quality and human well-being: a case study from a primary school in Turin (Italy)

Indoor green walls (IGWs) are innovative Nature-based Solutions to enhance air quality and thermal comfort in indoor spaces through bio-friendly design. At the same time, they can promote the improvement of human cognitive performance and socio-psychological wellbeing. A case study was developed and implemented in a primary school in Turin (Italy), through a collaborative process involving people from school, municipality, and academia, to prove the environmental and socio-psychological benefits of IGWs, based on impact assessment. The performance of IGW on air quality and human well-being was monitored, showing a positive impact of the IGW on indoor air quality through particulate matter (PM) removal, also highlighting interesting correlations between plant species, PM size fractions and their chemical composition. On the contrary, a low impact on the volatile organic compounds (VOCs) concentration was observed. Regarding the socio-psychological impact, despite the undoubtedly importance of the collaboration between various sectors of the public administration and of the use of IGW as a training tool for students, the impact evaluated by measuring changes in pupils’ pro-environmental attitude and behaviour was positive but lower than expected. In conclusion, this real-life case study provides results to be further used for evidence-based decision making about the implementation of IGWs in schools. However, the study also revealed some limitations and barriers in the effective implementation of impact monitoring in living context, such as primary schools. These challenges could provide valuable lessons learned for the implementation of similar projects in the future.