Conference PaperPDF Available

Natural Light and Productivity: Analyzing the Impacts of Daylighting on Students’ and Workers’ Health and Alertness

Authors:
International Conference on “Health, Biological and Life Science” (HBLS-16) April 18-19, 2016 Istanbul, Turkey
151
Abstract Recent studies show that the quality of the school
environment significantly influences students’ academic
performance. Among the many attributes of the school
environment, light is one of the most important ones. Lighting in
the classrooms has been subject of many studies for over a
century. In recent years, special attention has been given to the
impact of natural light on learning in the classrooms as light has
physiological, psychological and behavioral influences on school
children as well as workers. A multitude of surveys have indicated
also that daylight impacts the health and performance of children
in schools and that students’ health, satisfaction, attention, and
consequently performance are improved in the classrooms with
the help of natural light. This paper discusses the current
literature and evidence to evaluate the impacts of natural light on
students’ scholastic performance. Issues of timing and exposure to
daylight are also discussed in regard to health, alertness and
performance at school.
KeywordsDaylighting, Morning Sunlight, Students, Health,
Alertness
I. INTRODUCTION
Among many elements that impact building occupants, light
seems to have the most important impact. Light is an essence
for humans and it is known that has physical, physiological, and
psychological influences [1].
In the early part of the 20th century, natural light was the
primary source of building illumination. In a short span of a
couple of decades, electric lighting sources became the primary
source of illumination because of convenience mostly. In recent
years, energy conservation and environmental concerns have
changed those practices and brought daylighting is becoming
once again an important factor in building design [2]. For
decades, an appropriate lighting design was based on the
concept that it should meet the needs of the occupants
especially in terms of visual task performance as well as,
economical concerns. However, recent connections between
building occupants’ health and wellbeing and lighting has
brought the concept of lighting quality to the forefront of
environmental concerns in architectural design [1]. Recent
studies have proven that there is a correlation between lighting
F. N.Shishegar, Master of Architecture student at Illinois School of
Architecture, University of Illinois at Urbana-Champaign, USA (e-mail:
nshish2@illinois.edu).
S. M. Boubekri, Associate professor at Illinois School of Architecture,
University of Illinois at Urbana-Champaign, USA (e-mail:
Boubekri@Illinois.edu).
and humans’ performance and health. Light does not only
provide visual information but also constitutes a powerful
modulator of non-visual functions including state of alertness,
mental focus, and cognitive performance [3].
Light is also an important learning ingredient in the
classroom environment, as it appears to have strong influences
on cognition and learning. Research on electric lighting in the
classroom environment has received some attention over the
last few decades but research on the impact of natural light on
students in the classroom has been somewhat scarce [4]. The
very few studies in this area seem to show that windows and
daylight can enhance students’ physical and psychological
health, influence their mood, behavior and learning [5], [6]. Our
study presents a comprehensive review of recent work that
explored the relationship between daylight and students’ and
workers’ health and performance. In this regard, the influence
of morning sunlight on circadian system, brain activity and
alertness of students are discussed.
II. SPECTRAL CHARACTERISTICS OF DAYLIGHTNG AND
ARTIFICIAL LIGHTING
According to the Illuminating Engineering Society
“Daylighting refers to the art and practice of admitting beam
sunlight, diffuse skylight, and reflected light from the exterior
into a building to contribute to lighting requirements and
energy saving through the use of electric lighting controls”
[7].
Compared to natural light, artificial lighting provides a very
constant radiation field which could be turn on or off simply.
Spectral quality is a complicated term which is used to show
how warm or cool a light is (Correlated Color Temperature of
light, CCT) as well as the shift of color (Color Rendering
Index, CRI). Generally, the higher the CRI means the color of
an object will appear more accurately [8]. The sun generates a
broad spectrum of light in order to provide sufficient
wavelength for all people to recognize most colors. Therefore,
it is considered that the light from the sun has a CRI of 100
which is the maximum value a light can achieve [9].
Various studies have demonstrated the multitude of benefits
that daylight has in terms of its spectral qualities such as in the
generation of Vitamin D through our skin. In fact, this is the
nature of the light spectrum in sunlight that makes it unique in
improvement of human health and it could not be found in
electric lighting [8].
Natural Light and Productivity: Analyzing the Impacts of
Daylighting on Students’ and Workers’ Health and
Alertness
N. Shishegar, M. Boubekri
International Conference on “Health, Biological and Life Science” (HBLS-16) April 18-19, 2016 Istanbul, Turkey
152
III. DAYLIGHTING, HUMAN BODY, AND HEALTH
Humans are affected both physically and psychologically by
light. These effects are less quantifiable and consequently the
benefits of daylighting have been somewhat overlooked over
the years. Physically, light affects our bodies in two ways:
natural light interacts with our skin through photosynthesis and
produces vitamin D. Vitamin D facilitates calcium absorption
which strengthens our bones. Underexposure to sunlight causes
vitamin D deficiency which can result in a range of illnesses. In
the seventeenth century, vitamin D deficiency was attributed to
rickets. Between 1910 and 1930, researchers determined that
inadequate levels vitamin D causes abnormal bone frailty a
consequence of insufficient calcium in bones [8], [10].
In the second way, light is able to affects our metabolism and
our endocrinal and hormonal systems through our vision
system [8]. Recent studies have demonstrated that in addition to
illuminate task and provide visual comfort, natural light has
also an important non-visual impact on our biological processes
and is essential in synchronizing our circadian clock, in
stimulating blood circulation, and controlling the levels of
many of our hormones [11], [12].
For more than 150 years, scientists considered the rods and
the cones to be the only photoreceptors in the eye. In 2002, a
new stream in photobiology research –– demonstrated that
there is an alternative pathway from eyes to the brain. The new
pathway regulates various interactions between biological
functions and external luminous stimuli. New type of
photoreceptor in the retina of mammals was identified. This
new photoreceptor, a specific subtype of retinal ganglion cells,
describes the mechanism that light and darkness impact
humans’ biological systems [13].
Studies have also demonstrated that light influences health,
well-being, alertness, and sleep quality. Natural light affects
circadian rhythm, which is responsible for synchronizing
human’s body internal clock. Circadian rhythmicity in humans
is responsible for many cognitive processes such as attention,
executive functions and also memory. Generally, in cognitive
performance, circadian rhythms are influential through a
gradual enhancement during the biological day and a gradual
decline in performance during the biological night [3]. Light is
able to influence cognitive performance through its
synchronizing /phase-shifting impacts on the circadian clock.
As a results, exposure to natural light impacts brain cognitive
performance.
Impact of building daylighting on sleep quality has been
investigated in a limited number of studies. All of these studies
show that natural light exposure improves sleep quality of
building occupants such as office workers and students
[14]-[16]. Friborg and colleagues examined the role of several
self-regulatory variables such as mood, fatigue, behavioral
habits, as well as psychological self-regulation as moderators of
seasonality in sleep timing on 162 young participants in
Norway. The results of this study indicate that not only sleep
timing is delayed during the dark period (December) compared
to seasons with brighter photoperiods (September and March),
but also that seasonal sleep effects are followed by depression,
and to a lesser extent anxiety and fatigue. Inadequate daylight
reduced the circadian cycle [16]. As a result, melatonin is
secreted at the wrong times of the day causing chronic fatigue,
depression, and possibly other illnesses [1], [17].
Moreover, lighting affects mood and attitude. Daylighting
has been associated with improved mood, with an enhancement
of morale, lower fatigue, and reduced eyestrain. The seasonal
depression is considered as obvious evidence to prove the
relationship between natural light and human endocrinal
system. The seasonal depression usually found among people
living in northern latitudes is referred to as Seasonal Affective
Disorder (SAD) which describes the depression caused by lack
of daylight [8]. According to Avery and colleagues, more than
10% of the population of Finland and about 6% of that of the
United States suffer from this seasonal disorder [18].
Furthermore, many studies indicate that daylighting
enhances mental performance and decreases aggressive
behavior as well as depression [19]. Another advantage of
daylighting is its variability in its intensity throughout the day
and the seasons. In a research conducted by Hoffman and his
colleagues on the impact of different lighting conditions on
subjective mood in an experimental office showed that varying
lighting levels has a potential advantage for office workers as
far as their subjective mood [20]. Another important
psychological aspect resulting from daylighting is meeting our
need for contact with the outside world through daylight
apertures in buildings [21]. In this regard, daylighting has a
natural healing effect by its provisions of view to the outside
world. Daylighting can enhance a connection to nature and
directly improve the mood of the building occupants [22]. As
sown in TABLE 1 there is a multitude of physiological and
psychological benefits resulting from building daylighting.
TABLE I: NATURAL LIGHT AND HUMAN BODY
Natural light and human body
Physically
Psychologically
Decrease
Improve
Decrease
Cancer
Possibility
Mood
Depression
Abnormal
Bone
Formation
Mental
Performance
Stress
-
Alertness
Sadness
-
Brain activity
Violent
Behavior
IV. DAYLIGHTING AND PRODUCTIVITY
Many studies have attempted to correlate daylighting to an
improved productivity at the workplace. Boyce et al. defined
the productivity of an individual, or an organization, as the
ability of improving work production by increasing in either
quantity and/or quality of the product or service to be delivered
[23]. According to these authors there are three routes by which
lighting conditions can affect the performance of individuals:
(1) visual system, (2) circadian system, (3) and perceptual
system. Lighting conditions determines the capabilities of
visual system. As mentioned in previous paragraphs, the
circadian system is also influenced by light/dark cycle which is
related to lighting conditions directly [23]. Fig. 1 shows a
International Conference on “Health, Biological and Life Science” (HBLS-16) April 18-19, 2016 Istanbul, Turkey
153
conceptual framework for considering the relationship between
lighting conditions and human performance through the visual
system, circadian system and perceptual system [23].
Fig. 1. A conceptual framework setting out the routs by which lighting can
influence human performance. The arrows indicate the direction of the effects
[23].
Fig.2. Model of the impacts of light and lighting change on profitability in
the industrial environment [24].
Juslen and Tenner, present another conceptual model of the
influence of light and lighting condition changes on
productivity in the industrial environment [24]. This model is
shown in Fig. 2. The perspective behind this model is different
from that stated by Boyce et al. According to this study,
installing new lighting in the work environment affects the
performance of workers through several mechanisms. There are
at least 10 mechanisms that contribute to the enhancement of
people’s productivity including visual performance, visual
comfort, visual ambience, interpersonal relationships,
biological clock, stimulation, job satisfaction, problem solving,
the halo effect, and variability and changes in the environment
[24].
Other studies have evaluated the impact of natural light on
individuals’ productivity from other points of view such as
health, well-being, physical activity, motivation, achievements,
and etc. In the following paragraphs some of those studies will
be introduced.
Studies on the impacts of light on humans’ productivity date
back to 1920s. One of these early studies examined the impact
of lighting quality on silk weavers. In this study, Tennesen and
Cimprick [2] found out that people with views of natural
vegetation posed more attention during the work hours. The
view from windows is not the only important part of
daylighting techniques. Natural light increases attention and
alertness during the post-lunch dip and was shown to be helpful
in increasing alertness for mundane and repetitive tasks [21].
Another study conducted in the early 1990s showed that
employees of West Bend Mutual Insurance Company who
moved into a new building and who were provided with
personal control over their workstation environmental
attributes such as temperature, task lighting registered higher
performance overall compared to before the move. By moving
to a new building, the number of employees having a
workstation with a window view increased from 30% to 96%.
West Bend determined that compared to the old building, the
employees had a 16% increase in claims processing
productivity in the new building [19], [25].
Borisuit and colleagues evaluated the effects of daylighting
on office workers’ performance from the perspective of visual
comfort, alertness, and mood. The study was conducted on
twenty-five young subjects who spent two afternoons either
under electric light or daylighting conditions (without view
from the window). They found significantly higher visual
acceptance scores under daylighting than electric lighting
conditions, despite the lack of a direct outside views. While
subjective alertness and physical well-being decreased for both
lighting conditions in the course of the afternoon, subjects felt
sleepy earlier under electric lighting than daylighting. Physical
well-being became worse in the course of the afternoon under
electric lighting only. More visual comfort, alertness, and
well-being can be one of the indicators of office workers work
satisfaction and all of these factors enhance productivity as a
result [26].
Moreover, in another study, Boubekri and colleagues
examined the impact of daylight exposure on office workers’
productivity by considering subjective health, well-being, d
physical activity and sleep quality, all factors that have
significant influence on the productivity of individuals. Results
of this study indicate that office workers in offices without
windows reported poorer scores with respect to vitality,
physical activity and sleep quality in comparison to the group
with windows [14]. This same study revealed that office
workers with plenty of daylight throughout the day sleep on
average 46 minutes longer than their counterparts with no
daylight and windows. Other studies focused on absenteeism as
a gauge to measure productivity [27].
The fact that daylight seems to influence productivity in the
office setting could be extrapolated to the classroom
environment as well and one m ay hypothesize that daylighting
International Conference on “Health, Biological and Life Science” (HBLS-16) April 18-19, 2016 Istanbul, Turkey
154
influences students’ academic performance.
V. NATURAL LIGHT AND STUDENTS ACADEMIC
PERFORMANCE
The design of schools is to promote learning for children and
adults alike as well as optimize their physical and emotional
health. It should not be ignored that schools are among the most
crowded buildings most of the year and host young people.
Applying adequate daylighting techniques into the architecture
of a school contributes the occupants’ physical and emotional
health [28].
Students and teachers can benefit from integrating and
managing daylight properly. Saving energy, improved student
attendance, health and academic performance, and a less
stressful environment for students are only a few benefits of
adequate daylighting in educational environments [19]. Studies
show that teachers are happier when they have the ability to
control their environment. Healthy and happy teachers save
school money and have better performance in teaching [29]. In
contrast, a school with inadequate lighting design might demote
students’ ability of learning. Poor light spectral quality in
classrooms can create strain on students’ eyes and lead to a
decrease in information processing and learning ability as well
as higher stress levels in students [30].
Kuller and Lindsten studied children’s health and behavior in
classrooms with and without windows for an entire academic
year. They concluded that work in classrooms without windows
affected the basic pattern of the hormone cortisol, which is
related to stress, and could, therefore, have a negative effect on
children’s health and concentration. However, no direct
relationship was found between cortisol levels and student
performance and health [5], [28], [31]. In another study in
Sweden it was proved that observed behavior and circadian
hormone levels of elementary students in classrooms with
natural light stayed closer to expected norms in comparison
with students in classrooms with only fluorescent lighting [32].
Heschong and Mahone studied the impact of natural light
and students and found that the addition of natural light
improves student test score by up to 20% [32]. Taylor states
that students in classrooms with the most daylighting progress
20% and 26% faster in one year in math tests and reading tests
respectively compared to their counterparts in classrooms with
little or no natural light [33]. Another study conducted by Kim
et al. on daylight quality of educational facilities in high-rise
housing complexes in South Korea shows that daylight had an
influence on the quality of the educational environment, and
students’ learning performance [34].
Aggio et al. [35] evaluated the impact of light exposure on
the productivity of 229 students from the perspective of
physical activity and sedentary time (age mean = 8.8 years) in
Camden, UK. To investigate it, daily sedentary time, Moderate
and Vigorous Physical Activity (MVPA) and light exposure
were measured daily by using a tri-axial accelerometer with
ambient light sensor during the summer. The results of this
study illustrate that there are significant associations between
average daily light exposure and time sedentary and in MVPA.
Researchers concluded that average light exposure is positively
associated with time in MVPA and negatively associated with
sedentary time. Therefore, increasing daylight exposure might
be a useful intervention strategy for promoting physical activity
and consequently vitality and performance among young
Students [35].
Just like absenteeism in work environment, attendance is
another factor which could be considered a measure of
students performance. Schools that have integrated full
spectrum fluorescent or natural light show an increase in
student and teacher attendance when compared to traditionally
lit schools with lesser quality light fixtures. A study of the full
spectrum fluorescent Canadian schools reported that students
had an attendance increase of 3.2 to 3.8 more days per year than
students in traditional fluorescent lighting schools [19]. Durant
Road Middle School in Wake County school system in North
Carolina was especially designed to incorporate daylighting in
its classrooms. It reported the best health and attendance in the
entire school system and an attendance rate above 98%. The
school also claimed the lowest number of faculty health
absences in the area [19].
VI. IMPACT OF MORNING BRIGHT LIGHT ON STUDENTS
ALERTNESS AND PERFORMANCE
It should be considered that different spectrums of sunlight
have various impacts on humans’ body and particularly eyes. In
fact, visual and non-visual effects of light on brain functions
and responses are dependent on the specific wavelength of the
light received through the eye. As a result, morning sunlight
with a short wavelength spectrum influences people’s body
differently compared to long wavelength of afternoon sunlight.
It was observed that 6.5 hours exposure to blue light (460-nm
monochromatic light) during the biological night decreases
subjective sleepiness and enhances auditory performance and
alertness compared with exposure to an equal photon density of
green light (555-nm monochromic light) [36]. These findings
show that the alerting impacts of ocular light exposure are
wavelength dependent and there is a greater sensitivity to short
wavelengths in the visible spectrum. It was also observed that
even a few tens of seconds of light exposure brings about
immediate and significant wavelength-dependent changes in
the brain [39]. According to Vandewalle, 50 seconds exposure
to blue light increases activity in the left hippocampus, left
thalamus, and right amygdala, as compared to green light [37].
Morning light plays an essential role in the synchronization
of metabolic rhythms to the 24h rotational cycle of the Earth.
Without regular daylight entrainment, the human circadian
clock would run on average on a 24h and 15-30 minutes cycle,
ultimately leading to a shift of the circadian pacemaker, and a
desynchronisation of our biological clock. The impact of early
morning sunlight on students circadian system has been
investigated by Figueiro and Rea [38, 39] in the outside
laboratory conditions. This study showed that lack of
short-wavelength light in the morning brings about 30 minutes
delay in circadian phase for 8th-grade students. Other studies
showed similar results under controlled laboratory conditions.
The findings of the controlled laboratory results confirm those
found in real settings of school environments. Circadian rhythm
is largely responsible for numerous cognitive processes such as
attention, alertness, sleep quality, mood, as well as memory.
International Conference on “Health, Biological and Life Science” (HBLS-16) April 18-19, 2016 Istanbul, Turkey
155
These are key ingredients in the learning processes. Exposure
to natural light in the classrooms seems to be essential in
improving students learning.
The impact of morning exposure to daylight was also
examined by Keis et al. [40]. The results of this study prove that
the blue-enriched white lighting seems to have an effect on
basic information processing among high-school students. Blue
light appears to improve processing speed and concentration of
students compared to standard lighting. Furthermore, a recent
study showed that one hour of exposure to morning bright
white light advances sleep and wake-up parameters and affects
cognitive performance and alertness [41]. These studies
suggest that a sufficiently applied light intervention could
enhance alertness, and thus performance, at work significantly.
Other recent studies showed the effects of bright light on
healthy-active persons during regular daytime working hours.
A field study by Smolders, De Kort, and Van den Berg [42]
provided support for a direct link between exposure to more
intense light and feelings of vitality during daytime and in
everyday situations. Their results showed that hourly light
exposure was a significant predictor of vitality. People who
were exposed to more light experienced higher feelings of
vitality, over and above the variance explained by person
characteristics, time of day and activity patterns. Another
laboratory study showed that even in the absence of sleep and
light-deprivation, exposure to a higher illuminance at eye level
can induce subjective alertness and vitality, increase
physiological arousal and improve performance on a sustained
attention task [44]. The same results were found by Leichfried
et al. who concluded that that early morning illumination
improves subjective alertness and mood, but had no impact
melatonin level and mental performance of individuals [43].
Short exposure to light has been found to improve thalamic,
frontal, and parietal activities, and thus affects fatigue [38],
[44]. Moreover, as short-wavelength light is significantly
effective for phase-shifting the circadian pacemaker,
suppressing melatonin, and activating the autonomic nervous
system, studies suggest that long duration exposure of bright
light is an influential potential countermeasure for fatigue,
especially during the biological night. Routine tasks such as
driving which need sustain attention are improved by exposure
to bright light [38]. It can also positively affect cognitive as
well as physical performance in healthy individuals [45]-[47].
All these studies demonstrate a direct relationship between
intense early morning daylight and alertness, vitality, and
cognitive performance. All of these are key factors affecting
work and scholastic performance of individuals. Although
these studies have not assessed the impacts of morning daylight
on students’ alertness and productivity directly, they might be
extended to students. Considering the results of these studies, it
appears to be necessary to expose students to short bright light
during the early part of the day to maintain entrainment. These
findings seem to have significant and practical implications on
the design of schools in general and classrooms in particular.
Impacts of blue light in schools could be considered as a
simple, beneficial, non-pharmacological way which enhance
students’ health, alertness, brain activity, and vitality and
perhaps academic performance. Sunlight seems to be the most
appropriate lighting source in schools as it can deliver the
adequate quantity and spectrum as well as the proper timing
and duration of light exposure [38], [39]. These findings should
have direct implications on the layout of schools as well as
façade orientations and fenestration design in schools
VII. CONCLUSIONS
Among many elements in indoor environment, light seems to
have the most impacts on human body. Various studies have
investigated the impacts of light on people from different points
of view for over a century. These studies demonstrated that
light has visual and non-visual influences on people. Among
different source of lighting, it seems that sunlight is the most
effective one, as it comprises adequate quantity and a broad
spectrum of light. In addition, it is the most important source of
vitamin D which is necessary for human bones strength and
overall health. In addition to its role as an agent for vitamin D
production in human blood, natural light can improve
subjective mood, attention, cognitive performance, physical
activity, sleep quality, and alertness in humans. All these
factors could be considered key aspects for optimal academic
and work performance.
REFERENCES
[1] L. Bellia, F. Bisegna, and G. Spada, “Lighting indoor environment: visual
and non-visual light sources with different spectral power distribution,
Building and Environment, vol. 46, pp. 1984-1992, 2011.
[2] J.H. Heerwagen, “Green buildings, organizational success, and occupant
productivity,” Building Research and Information, vol. 28 (5), pp.
353-367, 2000.
[3] G. Vandewalle, P. Maquet, and D.J. Dijk,Light as a modulator of
cognitive brain function,” Trends in Cognitive Sciences, vol. 13, pp.
429438, 2009.
[4] L. Baker, A History of School Design and Its Indoor Environmental
Standards, 1900 to Today. Washington, DC: National Clearinghouse for
Educational Facilities, 2011, pp. 39-45.
[5] R. Kuller, C. Lindsten, “Health and behavior of children in classrooms
with andwithout windows. Journal of Environmental Psychology, vol. 12,
pp. 305-17, 1992.
[6] Heschong Mahone Group. Windows and Classrooms: A Study Of Student
Per-Formance And The Indoor Environment. Sacramento, CA:
California Energy Commission; 2003.
[7] IES RP-5-13. Recommended Practice for Daylighting Buildings.
Illuminating Engineering Society, 2013.
[8] Boubekri, M. Daylighting, Architecture and Health, NY: Architectural
Press, 2008.
[9] F. Sharp, D. Lindsey, J. Dols, J. Coker, “The use and environmental
impact of daylighting,” Journal of Cleaner Production, vol. 85, pp.
462-471, 2014.
[10] V.R. Garcia-Hansen, "Innovative daylighting systems for deep-plan
commercial buildings." PhD. Dissertation, Faculty of Built Environment
and Engineering, Queensland University of Technology, Brisbane, 2006.
[11] S. Altomonte, “Daylight and the Occupant, Visual and
physio-psychological well-being in built environment,” presented at 26th
Conference on Passive and Low Energy Architecture, Quebec City,
Canada, 22-24 June, 2009.
[12] W.J.M. Van [14], “Non-visual biological effect of lighting and the
practical meaning for lighting for work” Applied Ergonomics, vol. 37, pp.
461-466, 2006.
[13] W.J.M. Van Bommel, G.J. Van den Beld, “Lighting for work: a review of
visual and biological effects,” Lighting Research and Technology, vol. 36
(4), pp. 255-269, 2004.
[14] M. Boubekri, L. Cheung, K. Reid, C. Wang, &and P. Zee, Impact of
windows and daylight exposure on overall health and sleep quality of
office workers: A case- control pilot study,Journal of Clinical Sleep
Medicine, vol. 10(6), pp. 603-611, 2014.
[15] D. Aggio, L. Smith, A. Fisher, and M. Hamer,Association of light
exposure on physical activity and sedentary time in young people,
International Conference on “Health, Biological and Life Science” (HBLS-16) April 18-19, 2016 Istanbul, Turkey
156
International Journal of Environmental Research and Public Health, vol.
12, p p. 2941-2949, 2015.
[16] O. Friborg, J. Rosenvinge, R. Wynn, and M. Gradisar, “sleep timing,
phonotype, mood, and behavior at an arctic latitude (69°N). Sleep
Medicine, vol. 15, pp. 798807, 2014.
[17] R.G. Stevens, and M.S. Rea, M. S.,Light in the built environment:
potential role of circadian disruption in endocrine disruption and breast
cancer,Cancer causes and control, vol.12, pp. 279-287, 2011.
[18] D.H. Avery, D.N Eder, M.A. Bolte, C.J. Hellekson, D.L. Dunner, M.V.
Vitiello, and P.N. Prinz, “Dawn simulation and bright light in the
treatment of SAD: a controlled study,” Biological Psychiatry, vol. 50(3),
pp. 20516, 2001.
[19] L. Edwards, P. A. Torcellini, and N. R. E, A literature review of the
effectsof natural light on building occupants,” National Renewable
Energy Laboratory, 2002.
[20] G. Hoffmann, V. Gufler, A. Griesmacher, C. Bartenbach, M. Canazei, S.
Staggl, and M. Schobersberger, “Effects of Variable Lighting Intensities
and Color Temperatures on Sulphatoxymelatonin and Subjective
Moodin an Experimental Office Workplace,” Applied Ergonomics, vol.
39, pp. 719728, 2008doi:10.1016/j.apergo.2007.11.005.
[21] C.L. Robbins, Daylighting: Design and Analysis, New York: Van
Nostrand Reinhold, 1986.
[22] L. Gelfand, E. C. Freed, Sustainable School Architecture: Design for
Elementary and Secondary School, John Wiley and Sons Inc.
[23] P. Boyce, C. Hunter, and O. Howlett, The Benefits of Daylight through
Windows,Lighting Research Center, Rensselaer Polytechnic Institute,
New York, 2003.
[24] H. Jusle, and A. Tenner, “Mechanisms involved in enhancing human
performance by changing the lighting in the industrial workplace,”
International Journal of Industrial Ergonomics, vol. 35, pp. 843855,
2005.
[25] J.J. Romm and W.D. Browning, “Greening the building and the bottom
line - Increasing productivity through energy-efficient design,” Rocky
Mountain Institute, 1994.
[26] A. Borisuit, F. Linhart, J. Scartexxini, and M. Munch, Effects of realistic
office daylighting and electric lighting conditions on visual comfort,
alertness and mood, lighting Res,” Technol., [Online], vol. 0, pp. 1-18.
Available: lrt.sagepub.com.
[27] S. Markussen, and K. Røed,Daylight and absenteeism Evidence from
Norway,” Economics and Human Biology, vol. 16, pp. 7380, 2014.
1-s2.0-S1570677X14000252-main.
[28] A. Demir,Impact of daylight on student and teacher performance,
Journal of Educational and Instrutional Studies in the World, vol. 3 (1),
pp. 1-7, 2013.
[29] Johnson, Raymond, J. Leo, M. Bernabei, “Green Building Design for
Schools: The Next Time Around,Strategic Planning for Energy and the
Environment, vol. 26 (2), pp. 56-77, 2006.
[30] M. Anselm Dass, N. Ibrahim, N. Lukman, “Evaluation of daylighting at
public school classrooms in Ipoh, Perak,” Alam Cipta, vol. 7(1), pp.
27-34, 2014.
[31] National Research Institute (National Research Council), Green Schools:
Attributes for Health and Learning, Washington: The National
Academies Press, 2007.
[32] L. Heschong, L. Roger, S. Wright, “Daylighting impacts on human
performance in school. Journal of Illuminating Engineering Society
Summer, 101-114, 2002.
[33] A. Taylor and K. Engass, Linking Architecture and Education:
Sustainable Design For Learning Environments, China: University of
New Mexico Press, 2009.
[34] T. Kim, W. Hong, H. Kim, “Daylight evaluation for educational facilities
established in high-rise housing complexes in Daegu, South Korea,
Building and Environment, vol. 78, pp. 37-144, 2014,
http://dx.doi.org/10.1016/j.buildenv.2014.04.026
[35] D. Aggio, L. Smith, A. Fisher, and M. Hamer, “Association of Light
Exposure on Physical Activity and Sedentary Time in Young People,”
International Journal of Environmental Research and Public Health, vol.
12, pp. 2941-2949, 2015.
[36] S.W. Lockley et al. “Short-wavelength sensitivity for the direct effects of
light on alertness, vigilance, and the waking electroencephalogram in
humans,” Sleep Physiology, vol. 29, pp. 161168, 2006.
[37] G. Vandewalle, Brain responses to violet, blue, and green
monochromatic light exposures in humans: prominent role of blue light
and the brainstem,” PLoS ONE, vol. 2, pp. 1239-1247, 2007.
[38] M.G. Figueiro and M.S. Rea, Evening daylight may cause adolescents to
sleep less in spring than in winter,” Chronobiology International, vol. 27,
pp. 1242-1258, 2010a.
[39] M.G. Figueiro, M.S. Rea,Lack of short-wavelength light during school
day delays dim light melatonin onset (DLMO) in middle school students,”
Neuroendocrinology Letters, vol. 31, pp. 92-96, 2010 b.
[40] O. Keis, H. Helbig, J. Streb, K. Hille, “Influence of blue-enriched
classroom lighting on students’ cognitive performance, Trends in
Neuroscience and Education, vol. 3, pp. 86-92, 2014.
[41] R.W. Corbett, B. Middleton, J. Arendt, “An hour of bright white light in
the early morning improves performance and advances sleep and
circadian phase during the Antarctic winter,Neurocience Letters, vol.
525(2), pp. 146-151, 2012.
[42] K.C. Smolders, Y.A. De Kort, A.D. Tenner and F.G. Kaiser, “Need for
recovery in offices: Behavior-based assessment,” Journal of
Environmental Psychology, vol. 32, pp. 126-134, 2012.
http://dx.doi.org/10.1016/j.jenvp.2011.12.003.
[43] V. Leichtfred et al. “Intense illumination in the morning hours improved
mood and alertness but not mental performance, Applied Ergonomics,
vol. 46, pp. 54-59, 2015.
[44] G. Vandewall, et al., “Daytime light exposure dynamically enhances
brain responses,” Curr Biol, vol. 16(16), pp.161621, 2006.
[45] T. Kantermann, S. Forstner, M. Halle, L. Schlangen, T. Roenneberg, A.
Schmidt- Trucksass,The stimulating effect of bright light on physical
performance depends on internal time,” PLoS ONE, vol. 7 (7), pp.
406-55, 2012.
[46] A.B. Dollins, H.J. Lynch, R.J. Wurtman, M.H. Deng, K.U. Kischka,, R.E.
Gleason, H.R. Lieberman, “Effect of pharmacological daytime doses of
melatonin on human mood and performance,” Psychopharmacology
(Berl.), vol. 112 (4), pp. 490-496, 1993.
[47] F.A. Fraschini, D. Cesarani, D. Alpini, D. Esposti, B.M. Stankov,
Melatonin influences human balance,” Biol. Signals Recept. Vol. 8 (1-2),
pp. 111-119, 1999.
Studied at University of Illinois at Urbana-Champaign,
Nastaran Shishegar is an architect (M. Arch, MSc
Engineering, BSc) lighting specialist, and sustainability
expert who specializes in sustainable design and energy
efficient buildings. She has both researched and worked
on sustainable architecture and green buildings to
encourage industries and societies to save energy.
Nastaran’s research focuses on the sustainable
architecture, building energy performance, and
specifically, the impacts of daylighting and indoor environmental quality on
occupants’ health, satisfaction, and productivity. Her mission is to present a
greener world which is healthier and happier.
Dr. Mohamed Boubekri is a professor of architecture at
the University of Illinois at Urbana- Champaign. He is
a William Wayne Caudill Research Fellow, and twice a
Fulbright Fellow. Professor Boubekri’s research
focuses on sustainable architecture and the intersection
of the built environment and human health and
well-being. He has published more than 70 journal
articles and conferences papers. His first book,
published in 2008 with the Architectural
Press-Elsevier, explores the impact of daylighting of buildings on people’s
health and overall well-being. His second book published in September 2014
with Birkhäuser-Verlag explores the subject of daylighting and the health and
well-being of building occupants as well as design strategies and best practice
solutions.
... To enhance this productivity level, it was previously confirmed that exposure to nature enhances users' productivity [9]. Unfortunately, the indoor environment plays an indispensable part in individuals' day. ...
... Natural light is the primary source of vitamin D. Thus, those who do not receive enough sunshine may develop a deficiency of this vitamin. Problems with teeth, muscles, and bones can result from low vitamin D levels, which can have a domino impact on other areas of health [9]. Different theories, science fields, and design methods have discussed this effect of natural light. ...
... It was also highlighted that visual and brain fatigue caused by prolonged computer use can severely impair the cognitive functions of users, reducing the worker's productivity level. People who do not get enough natural light in their lives are more likely to notice a decrease in their mood and their productivity levels [9]. Accordingly, a growing amount of research has highlighted the role of some types of artificial lighting that copy the same motion, colors, and temperature as natural light, including the Circadian Light. ...
... Daylighting plays a vital role in modern architecture, offering numerous benefits. It reduces reliance on artificial lighting, lowers carbon emissions (Yu;Su, 2015), enhances productivity (Shishegar;Boubekri, 2016), and improves overall mood (Chen;Du, 2019). Exposure to natural light also supports healthy circadian rhythms, contributing to occupant well-being. ...
... Daylighting plays a vital role in modern architecture, offering numerous benefits. It reduces reliance on artificial lighting, lowers carbon emissions (Yu;Su, 2015), enhances productivity (Shishegar;Boubekri, 2016), and improves overall mood (Chen;Du, 2019). Exposure to natural light also supports healthy circadian rhythms, contributing to occupant well-being. ...
Article
Real-time monitoring and assessment of indoor illuminance are crucial for maintaining environmental quality, visual comfort, and building energy efficiency. Traditional systems struggle with complex layouts, but integrating real-time monitoring with smart building management enhances comfort and sustainability. This study presents an innovative method combining a CMOS camera, data processing, and deep learning algorithms. The camera captures continuous images and extracts texture features affected by lighting. A machine learning model then predicts the illuminance distribution, generating detailed light maps in real-time. This novel sensing system, validated through experiments at the University of Skikda, provides a promising solution to improve light management by optimizing daylight use, reducing energy consumption, and enhancing visual comfort. It offers architects and facility managers a tool to integrate real-time data into building management systems for more sustainable indoor environments.
... It is not only thermal comfort; adequate daylight and proper lighting also affect attentiveness in educational settings. Similarly, natural light can improve students' subjective mood, attention, cognitive performance, physical activity, sleep quality, and alertness (Shishegar N. & Boubekri M., 2016;Amalan et al., 2021). Three potential pathways are suggested for a daylight mechanism that improves human performance, increases visibility, enhances mood, and improves health. ...
Article
Full-text available
This study investigates optimizing classroom design by balancing thermal comfort and daylighting to enhance student attentiveness, a critical factor in educational settings. The research was motivated by the need to address the knowledge gap concerning the combined effects of thermal and visual comfort on student engagement, particularly considering gender differences, which have been underexplored in existing literature. Two identical lecture halls in Tiruchirappalli, India, were selected for the study: one with blackened windows and the other with standard windows. Field measurements of temperature, humidity, wind speed, and light levels were taken using a thermal comfort microclimate data logger and light meter, while student engagement and comfort were assessed through a questionnaire. The findings reveal that the lecture hall with standard windows provided superior visual and thermal comfort, resulting in higher levels of student attentiveness. In contrast, the hall with blackened windows showed reduced attentiveness. Additionally, gender analysis indicated that female students reported greater satisfaction with both thermal and visual comfort compared to their male counterparts. The study’s implications underscore the importance of integrating both thermal and visual comfort in classroom design, highlighting that optimal daylighting is essential for maintaining student attentiveness, even when thermal conditions are consistent. Furthermore, the research emphasizes the need for thoughtful design in educational spaces to create inclusive and effective learning environments that account for gender differences in comfort perception. This study contributes to the field by providing evidence that classroom design significantly influences student engagement and satisfaction, urging designers and educators to prioritize these factors in educational settings.
... Many studies 7 have confirmed that daylight has both visual and nonvisual effects on users, such as its impact on productivity, mood and feelings, alertness, and biological synchronization of the biological clock [5][6][7][8][9]. It also plays an important role in improving human behavior and sleep patterns. ...
Article
Full-text available
To highlight the essential role of lighting in higher education buildings, this field survey was conducted to explore students' subjective assessments of daylight utilization within the drawing halls in the architectural departments of higher educational buildings that located in Cairo, Egypt, and the surrounding areas. With 854 participants, the primary objective was to explore the participants' evaluation of the lighting source impact on students' satisfaction, preferences, moods, wellbeing and behavioral states. Additionally, it sought to measure the significance of daylight as a design factor. The research findings reveal that the importance of the provision of daylight is equal to that of achieving thermal comfort, an imperative consideration in Egypt's hot climatic context. It was found that daylight significantly enhances students' satisfaction within drawing halls. Moreover, it exerts a positive impact on students' moods, and behaviors, notably reducing the occurrence of psychological and physiological symptoms, such as stress and headaches, while promoting greater cooperation and interaction among students. This study highlights the fundamental role of daylight in the design of drawing halls, not only for its aesthetic qualities or energy conversation potential, but also for its profound impact on the well-being and students' satisfaction. It advocates for the strategic integration of daylight in educational facilities to create environments that are conducive to learning and holistic development.
... Daylight in buildings can be affected by various factors, including the surrounding environment and vegetation. Based on the studies mentioned, the impact of vegetation shading on building lighting and energy efficiency is undeniable [19]. ...
Article
Full-text available
An optimal supply of daylight has a positive effect on the physical and psychological health of building users. In the working environment, daylight is a decisive aspect that significantly determines the overall work efficiency of employees. Several factors influence the internal comfort of the environment, but one of the main factors is visual comfort. Nevertheless, excessive sunlight, especially in summer, can cause discomfort. Nowadays, there is a broad spectrum of elimination options for excessive solar gain. This contribution is devoted to a less discussed elimination option, specifically the shading of buildings by surrounding vegetation and its importance in an urbanized environment. The study evaluates the administrative premises of the building for education. The illuminance measurement was performed in two offices with the same orientation. Based on the measured values, the effectiveness of the shading by vegetation element in the current environment and time is detected. The paper aims to investigate the impact of shading by vegetation on the internal visual comfort of employees, based on the concept of daylighting, and recommend appropriate measures to achieve an optimal daylight level.
... Illumination, whether daylighting or electric lighting, has a significant impact on both the quality and speed of work [2,3]. Residents in northern cities are especially affected by seasonal changes in daylight hours, leading to disruptions in circadian rhythms that can impact cognitive performance, productivity, attention, and mood [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. ...
Article
Cities located north of the 60th parallel (Helsinki, Stockholm, Oslo, St. Petersburg etc.) are among those with a low amount of daylighting per year. The study aims to find the relationship between day-lighting and electric lighting in terms of its influence on human performance, attention, and general psychophysiological state. The length of daylight hours is significantly reduced in late fall, winter, and early spring. The short length of daylight hours usually affects the well-being of people living in northern cities. The study is provided by parallel methods: an online survey and an experiment to implement a comprehensive approach. The lack of daylighting had a significant impact on the psychophysiological state of respondents in an online survey. The respondents noted a decrease in work performance, apathy, sleepiness, and lethargy in the winter season. In the spring season, the respondents described their condition as satisfied, happy, good, and highly active. The negative aspects of the lack of daylighting were noticed both by the inhabitants of the cities on the 60th parallel to the northern latitude and by the inhabitants of the more southern cities (48th parallel to the northern latitude). In the experimental part, static lighting with increased horizontal illuminance (4000 К, 700 lx) and dynamic lighting (with scheduled changes) were compared. The analysis of the experimental data showed that under static lighting the participants noticed a high concentration of attention during the day. At the end of the work-day, they felt tired (headaches, tension, sore eyes). In the dynamic mode with the CCT change, the participants noticed that with the warm CCT they felt more relaxed, while with the cold CCT the concentration of attention increased. The participants rated dynamic lighting higher than static one. Dynamic lighting also has a positive effect on mental performance, selectivity of attention, and anxiety.
... It is well known that the aesthetics and psychological aspects of learning environments are heavily influenced by lighting, but its significance extends beyond basic visibility [23]. Of course, adequate lighting facilitates optimal visual comfort [24], but improved indoor lighting quality has also been linked to increased well-being [25,26], health [27][28][29], alertness [30,31], productivity [32,33], and cognitive performance [33-35] among students. Therefore, designing good classroom lighting is a crucial and complex challenge for designers. ...
Article
Full-text available
Humans are spending more time indoors than ever due to urbanisation and industrialisation, leading to higher electricity consumption in lighting systems. Recent research has demonstrated the significance of maintaining a balance between daylight and electric light to create an ideal learning environment that can significantly impact students’ academic performance. The objective of this study is to analyse the changes in students’ emotional response depending on the type of lighting in the classroom—whether it is daylight, electric light, or a combination of both. A field study was conducted with 521 university students to assess their affective response to the lighting environment inside their classroom. The results show that students prefer a Clear-efficient lighting environment for writing–reading tasks and a Soft-calm atmosphere for using electronic devices. For the paying attention tasks, a combination of daylighting and electric lighting is determined to be the best solution, while for the tasks of discussing–teamwork, students prefer daylighting. Daylighting is found to be the only lighting option that students like. Despite this, students still consider electric lighting and the combination of daylight and electric light adequate for a classroom. The findings of this study may help educators and designers create learning spaces that promote a positive and stimulating student environment by understanding the relationship between the lighting environment and students’ affective responses.
... Research shows that adequate ventilation blocks the proliferation of a range of respiratory diseases such as asthma, sick building syndrome, and more recently, COVID-19 (Lanthier-Veilleux et al., 2016;Lu, Lin, Chen, & Chen, 2015;Morawska & Cao, 2020). An abundance of studies associate access to natural light with lower stress levels, better maintenance of circadian rhythm, greater sleep duration and quality, increased alertness, and higher cognitive performance (Elzeyadi, 2011;Boubekri, Cheung, Reid, Wang, & Zee, 2014;Shishegar & Boubekri, 2016;Boubekri et al., 2020). Research on biophilic indoor design and views of green space show benefits to physiological and cognitive performance (Yin, Zhu, MacNaughton, Allen, & Spengler, 2018;Sanchez, Ikaga, & Sanchez, 2018;Gray & Birrell, 2014), recovery from stress (Li & Sullivan, 2015), and overall well-being (Gilchrist et al., 2015). ...
Article
Full-text available
Indoor environmental quality (IEQ) significantly impacts human health, well-being, and productivity. However, a comprehensive and in-depth review of the combined effects of IAQ and other multi-domain factors on human productivity is lacking. There has not been any prior review that encapsulates the impact of multi-domain factors on productivity and physiological responses of occupants. To address this gap, this review paper investigates and highlights the impact of IAQ and multi-domain factors (thermal, visual, and acoustic) on human productivity and occupant well-being in the built environment. The review explores various research methods, including evaluation of human productivity and creativity, data collection, and physiological signal analysis. We also examined the interactions between IAQ and multi-domain factors, as well as strategies for optimizing productivity through integrated building design and smart systems. The key findings from this review reveal that IAQ significantly impacts human productivity and occupant well-being, with interactions between IAQ and other IEQ factors further impacting these effects. Despite advances in the field, there are several limitations and gaps in the current research methods and study designs, including small sample sizes, limited and insufficient experimental design and control, reliance on laboratory or simulated environments, lack of follow-up and long-term data, and lack of robust performance metrics. The review proposes future research directions, including specific applications, and follow-up work to address these limitations and further advance the understanding of IAQ and multi-domain factors in the built environment. The implications of this review for policy and practice include the need for holistic and integrated approaches to IAQ and IEQ management, with a focus on creating healthy and productive indoor environments. This review emphasizes the importance of considering the complex interplay between IAQ and multi-domain factors, as well as the potentials of adopting smart control systems and sustainable design strategies to optimize productivity and occupant well-being in the built environment. By addressing these critical issues, we can enhance the overall quality of life for building occupants and contribute to a more sustainable future.
Technical Report
Full-text available
This is the 'second' school study on daylighting and view, looking at Fresno USD, for the CEC 2003. Much more detailed and nuanced than the first. There is also a detail appendix, which I will also upload.
Article
Full-text available
To investigate whether light exposure was associated with objectively measured physical activity (PA) and sedentary behaviour in young people. Participants (n = 229, 46.7% female) were young people (mean 8.8 years [SD ± 2.2]) from the borough of Camden, UK. Daily sedentary time, moderate and vigorous PA (MVPA) and light exposure were measured using a tri-axial accelerometer with an ambient light sensor during the summer. Multiple linear regression models examined associations between average daily light exposure, sedentary time and time in MVPA. Models were repeated investigating weekdays and weekend days separately. Analyses were adjusted for pre-specified covariables, including age, sex, device wear time, ethnic group, school and body fat. There were significant associations between average daily light exposure and time sedentary (β coefficient = -11.2, 95% CI, -19.0 to -3.4) and in MVPA (β coefficient = 3.5, 95% CI, 1.2 to 5.9). Light exposure was significantly associated with weekend sedentary time (β coefficient = -10.0, 95% CI, -17.6, -2.4), weekend MVPA (β coefficient = 3.7, 95% CI, 1.7, 5.7), weekday sedentary time (β coefficient = -15.0, 95% CI, -22.7 to -7.2), but not weekday MVPA (β coefficient = 2.0, 95% CI, -0.5 to 4.5). Average daily light exposure is positively associated with time in MVPA and negatively associated with sedentary time. Increasing daylight exposure may be a useful intervention strategy for promoting physical activity.
Article
Full-text available
Study objective: This research examined the impact of daylight exposure on the health of office workers from the perspective of subjective well-being and sleep quality as well as actigraphy measures of light exposure, activity, and sleep-wake patterns. Methods: Participants (N = 49) included 27 workers working in windowless environments and 22 comparable workers in workplaces with significantly more daylight. Windowless environment is defined as one without any windows or one where workstations were far away from windows and without any exposure to daylight. Well-being of the office workers was measured by Short Form-36 (SF-36), while sleep quality was measured by Pittsburgh Sleep Quality Index (PSQI). In addition, a subset of participants (N = 21; 10 workers in windowless environments and 11 workers in workplaces with windows) had actigraphy recordings to measure light exposure, activity, and sleep-wake patterns. Results: Workers in windowless environments reported poorer scores than their counterparts on two SF-36 dimensions--role limitation due to physical problems and vitality--as well as poorer overall sleep quality from the global PSQI score and the sleep disturbances component of the PSQI. Compared to the group without windows, workers with windows at the workplace had more light exposure during the workweek, a trend toward more physical activity, and longer sleep duration as measured by actigraphy. Conclusions: We suggest that architectural design of office environments should place more emphasis on sufficient daylight exposure of the workers in order to promote office workers' health and well-being.
Article
The book presents numerous examples of dynamic designs that are the result of interdisciplinary understanding of place. Taylor includes designer perspectives, forums derived from commentary by outside contributors involved in school planning, and a wealth of photographs of thoughtful and effective solutions to create learning environments from comprehensive design criteria. © 2009 by the University of New Mexico Press. All rights reserved.
Article
Lighting conditions in workplaces contribute to a variety of factors related to work satisfaction, productivity and well-being. We tested whether different photometric variables also influence visual perception and the comfort of the lighting, as well as subjective non-visual variables such as mood, alertness and well-being. Twenty-five young subjects spent two afternoons either under electric light or daylighting conditions (without view from the window). Subjects overall preferred the daylighting for visual acceptance and glare. Changes of photometric variables modulated changes in visual light perception, alertness and mood in the course of the afternoon. Finally, we found several associations of visual and non-visual functions, indicating a potential relationship of visual comfort with other circadian and wake-dependent functions in humans, which consequently could impact office lighting scenarios in the future.
Article
Light is a powerful zeitgeber that synchronizes our endogenous circadian pacemaker with the environment and has been previously described as an agent in improving cognitive performance. With that in mind, this study was designed to explore the influence of exposure to blue-enriched white light in the morning on the performance of adolescent students.58 High school students were recruited from four classes in two schools. In each school, one classroom was equipped with blue-enriched white lighting while the classroom next door served as a control setting. The effects of classroom lighting on cognitive performance were assessed using standardized psychological tests. Results show beneficial effects of blue-enriched white light on students׳ performance. In comparison to standard lighting conditions, students showed faster cognitive processing speed and better concentration. The blue-enriched white lighting seems to influence very basic information processing primarily, as no effects on short-term encoding and retrieval of memories were found.
Article
This study conducted a daylight evaluation of schools established in high-rise housing complexes in a Korean city. This was accomplished through a daylight simulation test and a questionnaire survey on students’ perception of and satisfaction with daylight in their classrooms. The simulation test showed that the amount of daylight to which a school was exposed could be affected by the surrounding high-rise housing complex, and that the distance between the complex and the school had an influence on the amount of daylight seen in classrooms. When the total daylight hours numbered less than four, or when the number of continuous daylight hours was less than two, students’ satisfaction with daylight was low. According to survey results, most students felt that daylight had an influence on their educational environment and learning performance. It is therefore deemed necessary to fully consider the surroundings when designing education facilities.
Article
With an expanding population and finite natural resources, it is critical to develop and implement energy-saving solutions that meet the needs of society without impacting future sustainability. LEED (Leadership in Energy and Environmental Design) certification is an effort to promote the selection and use of high-efficiency products. Within LEED, the use of energy-efficient lighting and daylighting (the use of natural sunlight for indoor lighting applications) is a focus. Daylighting is an area of significant research within the lighting industry and one of the largest areas of interest for those pursuing LEED certification. If designed and implemented correctly, daylighting can deliver environmentally neutral lighting to interior spaces. Once a daylighting system is installed, there is no ongoing impact as there is no pollution, no sources to maintain, no energy drawn, and little fixture maintenance required over the life of the product. There are a variety of daylighting designs in the marketplace, but limited information on how or where they are best utilized. If not properly utilized daylighting can result in ineffective lighting and unsatisfied consumers. Ineffective daylighting designs may cause users to revert back to more environmentally taxing lighting solutions. Additionally, ineffective implementation of daylighting can create a negative view of efficient lighting. This paper evaluates the design and implementation of various daylighting systems. It discusses three primary designs: skylights, solar concentrators, and tubular daylighting devices. Each design has unique uses and limitations. This paper is a brief guide to assist in the understanding and selection of daylighting technologies.
Article
This paper reports on a study of the effect of daylighting on human performance. In this project, we established a statistically compelling connection between daylighting and student performance. The methodology used to conduct this research is described and the results are presented and interpreted. For the schools study, data sets of student performance on standardized tests were correlated with information about the demographic characteristics of the students, the operation of the schools, and the physical conditions of classrooms. Each classroom was assigned a series of codes indicating the size and tint of its windows, the presence and type of any skylighting, and the overall amount and uniformity of daylight expected. The analysis included data on over 21,000 students in three distinctly different school districts. The three districts have different curricula and teaching styles, different school building designs and very different climates. A supplemental follow-up study explored the question of teacher bias in classroom selection The findings of this study indicate better student test scores in daylit classrooms, and suggest that there is an important relationship between daylight availability in buildings and human performance. Possible causal mechanisms are discussed, along with limitations of current findings and future research directions. The paper also presents an important methodology that may be applicable to other areas of lighting research.
Article
Objective: Daylight is an important zeitgeber for entraining the circadian rhythm to a 24-hr clock cycle, and especially within the Polar circle, which has long Polar nights several months each year. Phase delays in sleep timing may occur, but the mean shift is normally small. However, the individual variation in phase shifts is large, implicating moderating factors. Here we examined the role of several self-regulatory variables (mood and fatigue, behavioral habits and psychological self-regulation) as moderators of seasonality in sleep timing and chronotype. Patients/Methods: A sample of 162 young adults (76% females; mean age, f=23.4 yrs, m=24.3 yrs) participated in a prospective study across three seasons (Sep, Dec, Mar) in Tromsø/Norway at 69°39’N. Sleep diary and sleep/health-related questionnaire data were collected at each time point. Results: Sleep timing and chronotype were delayed during the dark period (Dec) compared with brighter photoperiods (Sep and Mar). Comparable effects were observed for insomnia, fatigue, mood (depression and anxiety), subjective health complaints, physical activity and school-related stress. Most importantly, depression and fatigue moderated the degree of seasonal shifting in sleep timing, whereas the other self-regulation indicators did not (i.e., eating habits, physical activity and psychological self-regulation). Conclusions: Seasonality in sleep timing and chronotype was confirmed, and depressive symptoms during the dark period seem to exacerbate phase shifting problems for people living in sub-Arctic regions.