Subjective well-beingResidential surrounding greennessMiddle-aged and older adultsMultilevel structural equation modellingBio-socio-behavioural pathwaysChinaLONG-TERM EXPOSURENATURAL OUTDOOR ENVIRONMENTSMENTAL-HEALTH BENEFITSPHYSICAL-ACTIVITYAIR-POLLUTIONLIFE-SATISFACTIONSOCIAL COHESIONBLUE SPACESNEIGHBORHOODSTRESS