Association between built environments and quality of life among community residents: mediation analysis of air pollution

The aim of this study was to analyze the relationship between built environments and quality of life (QoL), and the mediating role of air pollution in that relationship.This was a cross-sectional population-based study.Data of 5196 adults residing in 148 communities in three cities in Liaoning Province, China, were analyzed. Objective measures of traffic design included street connectivity, road network density, bus station density, and parking lot density; residential greenness was controlled as a confounder. QoL was evaluated using the 12-Item Short Form Health Survey. The average concentrations of PM2.5 and SO2 one month before QoL collection for each community were calculated.Road network density and parking lot density were negatively associated with the Physical Component Summary (PCS), but street connectivity was positively associated with PCS for the participants. Bus station density, street connectivity, and parking lot density were negatively associated with the Mental Component Summary (MCS), and PM2.5 and SO2 mediated this association. In addition, gender and road network density and parking lot density had an interactive effect on the MCS of the participants.Dense traffic affects people's health not only directly but also indirectly through air pollution. The effects of built environments and air pollution should be considered when building healthy, supportive communities, and healthy cities.