Routine greenery encounters and anxiety occurrence probability: a study of component contributions in university residential greenery scenes based on mobile electroencephalography data

Abstract

Introduction University students frequently encounter campus greenery during walking, queueing, and brief stops. Although green-space exposure has been associated with psychological restoration, the relationships between individual micro-scale greenery components and short-timescale anxiety-related electroencephalographic (EEG) responses remain unclear. This exploratory study examined associations between mobile EEG-derived Anxiety Occurrence Probability (AOP) and greenery components along an everyday campus route. Methods A residential greenery site at a university in Nanjing, China, was studied during summer. Thirteen greenery components were quantified along a fixed 45-m walking and queueing route. Mobile EEG data were collected from 38 university students, of whom 35 with valid data were included in the final analysis. AOP was derived from frontal alpha asymmetry and theta/beta ratio relative to individual resting baselines. 82 scene measurement points were established. Spatial mapping combined isovist-based visual fields and inverse distance weighting. Associations between greenery components and AOP were examined using correlation, multiple linear regression, ridge regression, and piecewise linear regression. Results AOP showed substantial spatial heterogeneity across the route. Color richness, shading rate, green view ratio, and visibility were negatively associated with AOP ( p < 0.05), whereas structural components showed no robust associations after accounting for multicollinearity. The regression model explained 79.8% of the variance in AOP (adjusted R 2 = 0.770; Cohen’s f 2 = 3.957). Piecewise regression identified breakpoints of 0.321 for shading rate and 0.451 for visibility, with bootstrap 95% CIs of 0.28–0.36 and 0.40–0.50, respectively. Discussion Routine, low-intensity encounters with several visual–spatial greenery components were associated with lower AOP in this sample. Given the single-campus, single-season, fixed-route observational design and absence of a non-green control route, these findings are correlational and do not establish causality. The estimated breakpoints should be considered context-specific reference values requiring validation in larger, multi-site and multi-season studies.