Health parks certification criteria: Assessing the psychological impact of natural features

Urban parks provide opportunities for psychological restoration, yet little research systematically examined how specific natural elements shape users’ perceptions and experiences across multiple outcomes. This study investigated the effects of five environmental indicators – blue element, floral coverage at 25% or 50%, chromatic floral biodiversity, and faunal biodiversity – on the evaluations of urban park images compared to a baseline park image. A sample of 200 Italian adults participated in a within-subject online survey, rating each AI-generated image on perceived restorativeness, place perception, liking, desire to visit, uniqueness, aesthetic value, restorative qualities, emotions, and place selection for emotion regulation. The research also examined whether place wellbeing affordances (naturalness, maintenance, safety, familiarity) mediated the effects of nature environmental indicators, and explored age and gender differences. Results: showed that images featuring indicators were evaluated more positively than the baseline across most outcomes, with blue elements and biodiversity features producing the strongest effects. Place wellbeing affordances partially mediated these effects, highlighting the role of perceived environmental quality in promoting positive experiences. Socio-demographic analyses revealed that younger adults generally rated images more positively, while older participants showed higher evaluations of uniqueness, aesthetic value, and desire to visit. Women were more sensitive to specific features, particularly blue elements and biodiversity, in their assessments of place restorativeness, pleasantness, and relaxation. These findings provide robust evidence that specific natural features enhance perceptual, affective, and restorative outcomes in urban parks, and underscore the importance of incorporating blue elements and biodiversity in urban design to guide effective urban planning in supporting user wellbeing.