A review on light in the built environment and its relationship to mental health outcomes

摘要

With an increased awareness of public mental health issues, more investigation is warranted in the mechanisms of how the built environment may influence an individual's mental health. Specifically, light research has shown progress in reducing negative mental health outcomes and lessons learned in that research may be informative in the built environment. For example, bright light therapy, bright light in the morning, low light in the evening, and exposure to natural light over artificial light positively influences mental health outcomes. Bright light in the morning and low levels of light in the evening reduces depression symptoms within a week. In contrast, bright light in the evening has an adverse effect on depression through modulation of individual's melatonin levels that alters the natural circadian rhythm affecting mood, sleep, and mental agility. The excretion of melatonin in individuals can be suppressed by light when its intensity exceeds approximately 2500 lux. In addition to the intensity, individuals are affected psychologically by the different spectrums of light. Artificial lighting does not usually contain the full spectrum lighting required for positive mental health outcomes, although full spectrum fluorescent lights contain the necessary color spectrum to cause positive mental health outcomes. Research suggest that natural light and full spectrum fluorescent lights have roughly the same color spectrum and both produce positive mental health outcomes. Due to the rise in urbanization and time in the urban built environment, architects and engineers may need to consider optimizing the built environment to include proper light exposure influencing positive mental health outcomes. Prior to design and modifications, it is recommended that can controlled studies to target specific light parameters and their relation to mental health outcomes be conducted.