scholarly journals VALIDATION OF SPECTRAL SIMULATION TOOLS FOR THE PREDICTION OF INDOOR ELECTRIC LIGHT EXPOSURE

2021 ◽  
Author(s):  
C. Pierson ◽  
M. Gkaintatzi-Masouti ◽  
M.P.J. Aarts ◽  
M. Andersen
Keyword(s):  
Light Exposure ◽  
Spectral Characteristics ◽  
Spectral Irradiance ◽  
Spectral Simulation ◽  
Simulation Tools ◽  
Lighting Conditions ◽  
Spectral Simulations ◽  
Electric Light ◽  
Indoor Lighting

As the interest in design applications related to responses to light beyond vision is growing, two simulation tools, ALFA and Lark, have been developed to incorporate spectral characteristics of light in the evaluation of indoor lighting conditions. The spectral characteristics of light are of particular relevance when studying ipRGC-influenced responses. This paper aims to assess the reliability of these tools in predicting indoor spectral irradiance specifically from electric lighting. Spectral irradiance was measured under three indoor electric lighting scenarios and compared against spectral irradiance simulated in ALFA and Lark. While the outcomes of the study tend to show that ALFA is both more accurate and faster, rather large errors were found for spectral irradiance (-28.6% to 33.4%). In comparison to a prior study focusing on daylighting, these results seem to indicate that spectral simulations of electrically lit scenes are generally less accurate than those of daylit scenes with these tools.

scholarly journals The Calculated Circadian Effects of Light Exposure from Commuting

2021 ◽  
Vol 11 (24) ◽  
pp. 11846
Author(s):  
Yihan Lu ◽  
Wenye Hu ◽  
Wendy Davis
Keyword(s):  
Circadian Rhythms ◽  
Light Exposure ◽  
Weather Conditions ◽  
Health Problems ◽  
Spectral Irradiance ◽  
Metropolitan Region ◽  
Circadian Regulation ◽  
Lighting Conditions ◽  
Indoor Lighting ◽  
Daylight Exposure

Light entrains human circadian rhythms, but increased time spent indoors and decreased daylight exposure may disrupt human circadian regulation and cause health problems. Much research is focused on improving indoor lighting conditions to minimize the adverse circadian impact of electric lights, and few studies investigate the circadian impact of daylight during the incidental time that people spend outdoors. For instance, when people commute from home to work, they are exposed to daylight. The purpose of this study is to investigate daylight’s impact on commuters’ circadian rhythms. Measurements of the illuminance and the spectral irradiance distribution (SID) of daylight were taken for three modes of commuting: driving, riding on trains, and walking; and under different weather conditions, on different days, and at different locations throughout the summer and autumn in the Sydney metropolitan region in Australia. With the SID data, three metrics were calculated to estimate the circadian impacts: α-opic irradiance, circadian stimulus (CS), and equivalent melanopic lux (EML). The results suggest that driving or walking on sunny or cloudy days and riding trains on sunny days are beneficial for the commuters’ circadian synchronization.

scholarly journals Light and chronobiology: implications for health and disease

2012 ◽  
Vol 14 (4) ◽  
pp. 448-453 ◽  
Keyword(s):  
Cognitive Performance ◽  
Light Exposure ◽  
Biological Clock ◽  
Spectral Composition ◽  
Light Therapy ◽  
Lighting Conditions ◽  
Environmental Light ◽  
Health And Disease ◽  
Peripheral Clocks ◽  
Indoor Lighting

Environmental light synchronizes the primary mammalian biological clock in the suprachiasmatic nuclei, as well as many peripheral clocks in tissues and cells, to the solar 24-hour day. Light is the strongest synchronizing agent (zeitgeber) for the circadian system, and therefore keeps most biological and psychological rhythms internally synchronized, which is important for optimum function. Circadian sleep-wake disruptions and chronic circadian misalignment, as often observed in psychiatric and neurodegenerative illness, can be treated with light therapy. The beneficial effect on circadian synchronization, sleep quality, mood, and cognitive performance depends on timing, intensity, and spectral composition of light exposure. Tailoring and optimizing indoor lighting conditions may be an approach to improve wellbeing, alertness, and cognitive performance and, in the long term, producing health benefits.

Influence of the perceived size of a light source on non-visual effects in humans

2020 ◽  
Vol 9 (6) ◽  
pp. 385-393
Author(s):  
Arvid Niemeyer ◽  
Lucia Rottmair ◽  
Cornelius Neumann ◽  
Cornelius Möckel
Keyword(s):  
Working Memory ◽  
Light Exposure ◽  
Error Rates ◽  
Positive Contribution ◽  
Measurement Point ◽  
Visual Effects ◽  
Lighting Conditions ◽  
Light Measurement ◽  
And Performance ◽  
Main Effects

AbstractLight not only enables humans to perceive their surroundings, but also influences their sleep–wake cycle, mood, concentration and performance. Targeted use of these so called nonvisual effects could also have a positive contribution in automobiles by keeping passengers alert, minimizing error rates or bootsting attention in general. Since construction space in vehicle interios is scarce, this study compared the influence of differently-sized light panels and thus solid angles on nonvisual effects. In a counterbalanced order, 32 volunteers were exposed to three lighting conditions in the morning: baseline (12 lx, 2200 K), small (200 lx, 6500 K, 0.05 sr) and large (200 lx, 6500 K, 0.44 sr). During each session of 60 min, alertness, concentration and working memory were assessed before and during light exposure. After data analysis no significant main effects of light, measurement point or interaction between light and measurement point could be seen.

scholarly journals Light, Alertness, and Alerting Effects of White Light: A Literature Overview

2018 ◽  
Vol 33 (6) ◽  
pp. 589-601 ◽  
Author(s):  
Renske Lok ◽  
Karin C. H. J. Smolders ◽  
Domien G. M. Beersma ◽  
Yvonne A. W. de Kort
Keyword(s):  
White Light ◽  
Light Exposure ◽  
Neural Mechanisms ◽  
Dependent Manner ◽  
Experimental Paradigm ◽  
Research Paradigms ◽  
Lighting Conditions ◽  
Literature Overview ◽  
Dose Dependent ◽  
As Effects

Light is known to elicit non–image-forming responses, such as effects on alertness. This has been reported especially during light exposure at night. Nighttime results might not be translatable to the day. This article aims to provide an overview of (1) neural mechanisms regulating alertness, (2) ways of measuring and quantifying alertness, and (3) the current literature specifically regarding effects of different intensities of white light on various measures and correlates of alertness during the daytime. In general, the present literature provides inconclusive results on alerting effects of the intensity of white light during daytime, particularly for objective measures and correlates of alertness. However, the various research paradigms employed in earlier studies differed substantially, and most studies tested only a limited set of lighting conditions. Therefore, the alerting potential of exposure to more intense white light should be investigated in a systematic, dose-dependent manner with multiple correlates of alertness and within one experimental paradigm over the course of day.

scholarly journals The Influence of Light Exposure in Ambiance during Pregnancy in Maternal and Fetal Outcomes: An Experimental Study

2018 ◽  
Vol 41 (01) ◽  
pp. 024-030
Author(s):  
Vitor Sarri ◽  
Beatriz Ferrari ◽  
Larissa Magalhães ◽  
Paula Rodrigues ◽  
Almir Rezende ◽  
...  
Keyword(s):  
Light Exposure ◽  
Good Practice ◽  
Histological Evaluation ◽  
Reproductive Parameters ◽  
Anthropometric Measures ◽  
Dark Light ◽  
Mean Values ◽  
Lighting Conditions ◽  
Significant Difference ◽  
Environmental Lighting

Objective The aim of this study is to evaluate whether exposure to different environmental lighting conditions affects the reproductive parameters of pregnant mice and the development of their offspring. Methods Fifteen pregnant albino mice were divided into three groups: light/dark, light, and dark. The animals were euthanized on day 18 of pregnancy following the Brazilian Good Practice Guide for Euthanasia of Animals. Maternal and fetal specimens were measured and collected for histological evaluation. Analysis of variance (ANOVA) test was used for comparison of the groups considering p ≤ 0.05 to be statistically significant. Results There was no significant difference in the maternal variables between the three groups. Regarding fetal variables, significant differences were observed in the anthropometric measures between the groups exposed to different environmental lighting conditions, with the highest mean values in the light group. The histological evaluation showed the same structural pattern of the placenta in all groups, which was within the normal range. However, evaluation of the uterus revealed a discrete to moderate number of endometrial glands in the light/dark and light groups, which were poorly developed in most animals. In the fetuses, pulmonary analysis revealed morphological features consistent with the transition from the canalicular to the saccular phase in all groups. Conclusion Exposure to different environmental lighting conditions had no influence on the reproductive parameters of female mice, while the offspring of mothers exposed to light for 24 hours exhibited better morphometric features.

scholarly journals A conceptual simulation workflow to guide design decisions regarding the effects of daylight on occupants’ alertness

2021 ◽  
Vol 2042 (1) ◽  
pp. 012116
Author(s):  
Pierson Clotilde ◽  
Soto Magán Victoria Eugenia ◽  
Aarts Mariëlle ◽  
Andersen Marilyne
Keyword(s):  
Light Exposure ◽  
Well Being ◽  
Research Field ◽  
Decision Makers ◽  
Spectral Simulation ◽  
Design Decisions ◽  
Computational Tools ◽  
Recent Developments ◽  
The Impact

Abstract Recent developments in the lighting research field have demonstrated the importance of a proper exposure to light to mediate several of our behavioral and physiological responses. However, we spend nowadays around 90% of our time indoors with an often quite limited access to bright daylight. To be able to anticipate how much the built environment actually influences our light exposure, and how much it may ultimately impact our health, well-being, and productivity, new computational tools are needed. In this paper, we present a first attempt at a simulation workflow that integrates a spectral simulation tool with a light-driven prediction model of alertness. The goal is to optimize the effects of light on building occupants, by informing the decision makers about the impact of different design choices. The workflow is applied to a case study to provide an example of what learnings can be expected from it.

scholarly journals Telling the Seasons Underground: The Circadian Clock and Ambient Temperature Shape Light Exposure and Photoperiodism in a Subterranean Rodent

2021 ◽  
Vol 12 ◽  
Author(s):  
Danilo E. F. L. Flôres ◽  
Milene G. Jannetti ◽  
Giovane C. Improta ◽  
Patricia Tachinardi ◽  
Veronica S. Valentinuzzi ◽  
...  
Keyword(s):  
Circadian Clock ◽  
Laboratory Experiments ◽  
Light Exposure ◽  
Seasonal Patterns ◽  
Subterranean Rodents ◽  
Subterranean Rodent ◽  
Lighting Conditions ◽  
Oscillatory Structure ◽  
Exposure Patterns ◽  
Living Organisms

Living organisms anticipate the seasons by tracking the proportion of light and darkness hours within a day—photoperiod. The limits of photoperiod measurement can be investigated in the subterranean rodents tuco-tucos (Ctenomys aff. knighti), which inhabit dark underground tunnels. Their exposure to light is sporadic and, remarkably, results from their own behavior of surface emergence. Thus, we investigated the endogenous and exogenous regulation of this behavior and its consequences to photoperiod measurement. In the field, animals carrying biologgers displayed seasonal patterns of daily surface emergence, exogenously modulated by temperature. In the laboratory, experiments with constant lighting conditions revealed the endogenous regulation of seasonal activity by the circadian clock, which has a multi-oscillatory structure. Finally, mathematical modeling corroborated that tuco-tuco’s light exposure across the seasons is sufficient for photoperiod encoding. Together, our results elucidate the interrelationship between the circadian clock and temperature in shaping seasonal light exposure patterns that convey photoperiod information in an extreme photic environment.

Sign in / Sign up

Export Citation Format

Share Document