Restorative potential of greenspaces in noise-polluted environments (RESTORE)

Urban densification often entails an increase in noise burden and a reduction of green spaces. This exposes residents to more stress and impedes outdoor recreation. The RESTORE project investigated if and how far green spaces facilitate, and road traffic noise impedes restoration from stress. It followed a comprehensive research approach: i) laboratory experiments in which subjects were exposed to VR settings composed of loud, quiet, natural and/or built environments; ii) field experiments with group walks through physical sets of these environments; iii) a field study in the city of Zurich among residents with different noise exposure and access to greens paces; iv) a Swiss-wide participatory GIS survey assessing the physical and perceived characteristics of places chosen for restoration.

We could prove that green spaces support and noise impedes restoration. Not only were the walks in natural settings perceived as more restorative than in built environments, but also within the quieter environment for a given setting (natural vs. built). The VR experiments support these findings and, in addition, showed that natural sounds decreased physiological stress (skin conductance) more than anthropogenic sounds, even when presented in a visual built environment. The Swiss-wide survey revealed that people usually choose places for restoration that are greener and quieter than their home environments. However, the higher the noise exposure at home, the louder the available nearby locations for restoration. Traffic noise was mentioned as a major obstacle to restoration, beside personal sorrows and crowdedness of the place. Finally, the field study in Zurich revealed that green spaces in the neighborhood not only alleviate noise annoyance but are also associated with lower concentrations of chronic stress biomarkers (hair cortisol).

RESTORE thus underlines for urban planning that green spaces should be easily accessible, extensive and provide a relatively quiet and natural soundscape.