Relationship between visibility of urban green and blue space and mental health: Evidence from the capital city of New Zealand

Background: As urbanization escalates globally, urban neighbourhood features which improve physical and, more recently, mental health are of growing importance. One area of exploration is the role of visibility of green/blue space.

Objective: To quantify visual exposure to green/blue space using novel spatial methodologies and to investigate whether visibility was associated with psychological stress (K-10) in a national adult sample.

Methods: Novel visibility measurements were created for blue/green space to account for the distance, slope, aspect and relative elevation of visible areas from each population-weighted neighbourhood viewpoint. We fitted separate cluster robust linear regression models for K-10 scores and visibility measures, adjusted for age, sex, personal income, and neighbourhood population density, crime and deprivation.

Results:

We did not detect a significant association between total green space visibility and K-10 scores. By distance bands, we found that green space visibility only at distances 3-6km and 6-15km were associated with decreased psychological stress (β = -21, p = 0.01 and β = -0.15, p = 0.06). For blue space, we found increased visibility was associated with decreased psychological stress (β = -0.32, p <0.001). Personal income (in all models), neighbourhood deprivation and population density (in several models) also exhibited significant independent effects on K-10 scores.

Conclusion:

These results suggest that increased visibility of blue space generally and of distant green space have a salutogenic effect and may play a role in psychological stress reduction.