A Cross-sectional Survey Assessing the Effect of Indoor Environmental Factors on Mental Health

Objectives: The residential environment is known to affect physical and mental well-being. This cross-sectional study aimed to examine the associations between perceived indoor environmental quality (IEQ) and mental health (depression, anxiety, and stress) among adults in the Kingdom of Saudi Arabia. Material and Methods: A cross-sectional online survey recruited Saudi residents ≥18 years (n = 451) in March 2025–April 2025. Measures included a 13-item IEQ scale (thermal, acoustic, lighting, spatial, ventilation, and air quality indicators) and the Arabic depression, anxiety, and stress scale (DASS)-21. Results: DASS scores indicated mild–moderate depression (M = 11.48) and anxiety (M = 11.84), and moderate stress (M = 14.69). IEQ ratings were generally moderate. Larger room size, greater daytime comfort (temperature, noise, lighting), and higher ventilation satisfaction correlated with lower DASS scores, whereas more frequent unpleasant odors correlated with higher DASS scores. Participants who reported no primary noise source had the lowest DASS scores; inside-room and adjacent-room noise sources showed the highest scores. In regression models, lower odds of moderate–severe depression were associated with higher daytime comfort (temperature, noise, and lighting), greater room-size satisfaction, and ventilation satisfaction, while unpleasant odors increased the odds. For anxiety, protective predictors included daytime comfort (temperature, noise, and lighting), nighttime noise comfort, room and window size, and ventilation; unpleasant odors increased the odds. Conclusion: These findings show that participants’ perceived comfort at home is meaningfully associated with their mental health. They highlight that multiple modifiable IEQ factors, especially daytime thermal, acoustic, and lighting comfort, spatial adequacy, ventilation, and odor control, are associated with depression, anxiety, and stress. Such findings underscore practical targets for residential mental-health promotion in hot-arid contexts.