Urban built environment, environmental exposures and mental health in a dense Mediterranean city

The urban built environment and environmental exposures such as road traffic noise and ambient air pollution could affect mental health, but it's unclear how these factors interact. We aimed to study these factors simultaneously to holistically evaluate the impact on mental health. This cross-sectional study was based on a population-based sample of 3216 individuals aged 15-97 years residing in Barcelona, Spain that participated in the Barcelona Health Survey 2016. A face-to-face interview was carried out by trained interviewers at the respondent's residence. We characterized the built environment (e.g. facility richness), road traffic noise, and ambient air pollution at the residential level using a geographical information system (GIS). Mental health was assessed with the 12-item General Health Questionnaire. Built environment, road traffic noise and air pollution indicators were low-to-moderately correlated with each other. Higher facility richness was associated with a higher likelihood of poor mental health, while living in higher altitude areas appeared to benefit mental health. Noise and air pollution indicators were associated with poor mental health, but this was only statistically significant for coarse particulate matter. This cross-sectional study shows that characteristics of the built environment and air pollution were associated with mental health. Further analysis is needed to shed light on interrelations between these factors and pathways to poor mental health.