Neighborhood social contact and cohesion mediate the relationship between subjectively perceived artificial light at night and mental wellbeing.

Artificial Light at Night (ALAN) may improve health by promoting increased social activity. However, this hypothesis still lacks empirical evidence. In this study, we conducted an online survey to investigate the relationship between both subjective and objective measures of artificial light at night (ALAN) and mental wellbeing among 646 adults across 27 provinces in China. Additionally, we explored the potential mediating role of social contact and social cohesion within neighborhoods. Objective ALAN data were obtained through remote sensing technologies, while subjective ALAN exposure, social contact, and social cohesion were assessed via pre-established survey instruments. We found a non-linear relationship between subjective ALAN and mental wellbeing: subjective ALAN scores within the range of 6-11 (out of a total of 11) were positively correlated with mental wellbeing. This association was largely explained by neighborhood social contact and social cohesion, particularly among men. These results underscore the bright side of ALAN and provide a mechanism for understanding the health benefits of ALAN.