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. 2020 Feb 28;2(1):61–85. doi: 10.3390/clockssleep2010008

Table 6.

Gaps in knowledge of daylight research related to environmental factors.

Impact of latitude, time zones, climate
Seasonal changes Does exposure to seasonal changes in day length have consequences for human physiology and health, as some of the existing literature suggests [79,111,207,208]?
Latitude In those most vulnerable e.g., living at high latitudes, light therapy and improved home/work lighting has been shown to be useful for winter depression and sleep disorders, given that there is insufficient daylight for some months of the year [209,210].
Location within time zone Does the location within a time zone modify daylight’s effect on an individual’s circadian phase [208,211]?
Daylight saving time (DST) Is there a long-term effect of daylight saving time [212,213,214,215] on wake and sleep physiology?
Micro/macroclimate How does ambient temperature, humidity, and air pollution modulate daylight’s effects on physiology?
Rural vs. urban environments Is there a difference in daylight exposure dose between those living in rural vs. urban environments?
Architecture, urban design
Daylight conditions in buildings What role do the complex daylight conditions in buildings, such as building orientation, window positioning, glazing, play on visual comfort/adversity (glare), productivity and performance, circadian entrainment and health in general [32,216,217]? Could architecture be deployed to accentuate spatial-temporal modulation of daylight to stimulate retinal photoreception?
Glazing How do single vs. double vs. triple glazing systems, electrochromic windows, and new technologies such as smart windows with integrated micro-daylighting systems influence health [218]? How effective is dynamic glazing in order to address heat emission and light?
Floor orientation, spatial distribution of daylight How does the location of apartments (floor and geographical orientation) within a given building, and the indoor spatial distribution of daylight, affect human health?
Daylight enhanced qualities What design can provide daylight-enhanced qualities in single buildings and urban settings?
Complementation with electrical light/daylight systems How can the geographical orientation of a building, which determines its indoor light intensity, be compensated/complemented with daylight systems/electric light?
(Day-) light control systems How should modern (light) sensor and controller technology be used to support health, performance, and well-being of its inhabitants?
Self-control of (day-) light How much self-control over sensor control is necessary and desired [219]?
Alienation from nature What are the consequences of losses of daylight/weather/seasonal effects due to urban densification, loss of daylight recreation areas, daylight restriction due to high buildings etc. on mood, health and quality of life [69,220,221,222,223]?
Role of view Low daylight exposure and daylight deprivation usually also means deprivation from a view. This could have additional and far-reaching negative consequences, although research to date is scarce [223].