Perceived commuting stress, residential nighttime light, and mental health: an environmental stress perspective.

Daily environmental stressors embedded in urban life may influence mental health not only through direct exposure but also through the ways individuals perceive and respond to these demands. Among these stressors, commuting represents a recurrent daily burden whose psychological impacts may vary according to the surrounding residential environment. This study integrates satellite-derived nighttime light (NTL) exposure with individual-level survey data to examine the relationships among objective commuting conditions, perceived commuting stress, and mental health outcomes, as well as the moderating role of residential nighttime environments. Using data from 7,093 working adults in Jiayuguan City, China, we conceptualize commuting stress within a stress-process framework that distinguishes objective commuting conditions from subjective stress appraisal. A Perceived Commuting Stress Index (PCSI) was developed to capture integrated psychological responses to commuting experiences. Multivariable regression and structural equation modeling showed that objective commuting characteristics were associated with perceived stress, depressive symptoms, and anxiety primarily through perceived commuting stress, highlighting the central mediating role of subjective appraisal. Residential NTL exposure showed limited direct associations with mental health outcomes but strengthened the association between commuting stress and both perceived stress and depressive symptoms. These patterns were consistent with the possibility that nighttime urban environments may interfere with recovery-related processes under elevated commuting burden. The findings illustrate how satellite-derived NTL exposure can contribute to mechanism-oriented urban health research by capturing environmental contexts relevant to stress and mental health.