Abstract
Urbanization across Europe has intensified concerns regarding mental health, positioning the availability of urban natural environments as a critical public health determinant. This cross-sectional study investigated the relationship between residential green space availability and mental well-being indicators across four densely populated European metropolitan areas: Paris, Berlin, Madrid, and Milan. Geocoded residential addresses of 12,450 adult participants from cross-sectional health surveys were linked with high-resolution geospatial data. Surrounding greenness was quantified using Sentinel-2 Normalized Difference Vegetation Index (NDVI) within 300-meter and 500-meter circular buffers, while access to formal green infrastructure was evaluated via European Urban Atlas cartography measuring network distance to public parks. Mental well-being outcomes were assessed using the World Health Organization-Five Well-Being Index (WHO-5) and the Generalized Anxiety Disorder 7-item (GAD-7) scale. Multilevel mixed-effects linear and logistic regression models adjusted for age, sex, socioeconomic status, physical activity, and neighborhood deprivation. An interquartile range increase in residential NDVI within 300 meters was significantly associated with higher WHO-5 scores (β = 2.84, 95% CI: 2.12, 3.56) and reduced odds of moderate-to-severe anxiety symptoms (AOR = 0.81, 95% CI: 0.74, 0.89). Proximity to public parks within 400 meters independently conferred positive psychological benefits. Interaction analyses indicated that individuals residing in socioeconomically disadvantaged districts experienced the greatest relative mental health benefit from local greenness. These findings provide empirical support for urban planning interventions targeting green infrastructure expansion as an equitable strategy for population-level mental health promotion.
