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Light Pollution: Adverse Health Impacts
Published in Tuan Anh Nguyen, Ram K. Gupta, Nanotechnology for Light Pollution Reduction, 2023
Manish Srivastava, Anjali Banger, Anjali Yadav, Anamika Srivastava
The darkness of the night has been used in many ways by plants whether we talk about their metabolic processes, photoperiodic regulation of their growth and development, or their functions. Plants functions according to the brightness in the daytime and the darkness of the nighttime. Their activities and functions vary with the period and duration of the day and the night. Continuous exposure to artificial light could lead to adverse consequences which directly or indirectly affect the growth, metabolism, and development of the plant (Figure 6.4). Accordingly, short-day plants need longer nights for their growth while long-day plants need a shorter night duration. If a short-day plant gets illuminated or irradiated with an artificial source of light during the night even for a short duration, it will react accordingly and construe it as a short night. Its functions, growth will get completely episodic. In normal conditions, these plants usually blossom during the autumn season when the length of the days is shorter. They make use of the longer nights to begin the onset of flowering and with time as the night lengthens, they get into the dormant state [16].
The course of the sun over an observer on the ground
Published in Lucien Wald, Fundamentals of Solar Radiation, 2021
Daytime, or daylength, is defined as the period of time during which the sun is above the horizon during a day of 24 h. Daytime is noted Sday and is given in h by: Sday=(tsunset−tsunrise)=(12/π)(ωsunset−ωsunrise)
Case studies
Published in Sven Ruin, Göran Sidén, Small-Scale Renewable Energy Systems, 2019
The energy storage in reservoirs and hydroelectric power is very important for this solution with solar power. It enables energy to be stored from the daytime, when the solar radiation is intense, until evening and night. There are also other possible options for short-term storage. One prerequisite, of course, is that one can create a stable electricity grid independent of the diesel power plants.
Effects of window status and indoor plants on air quality, air temperature, and relative humidity: a pilot study
Published in Journal of Asian Architecture and Building Engineering, 2023
The window manipulation was randomly decided based on the Excel random number generator by separately measuring the indoor air characteristics when the window was opened and when the window was closed. The window glazing was 1.55 m × 0.62 m in dimension. Further, the manipulation for daylight duration was performed by keeping the light on from 6 a.m. to 6 p.m. (12 h), defined as daytime, and the mean illuminance at the top of the plants was about 559.5 lux. Conversely, the period between 6 p.m. and 6 a.m. of the next day was regarded as nighttime, during which the light was turned off. Given that the experimental room was in the basement, the illumination inside the room was minimally affected by the skylight. The major difference of illuminance between day time and night time was the light in the room.
Association between Perceived Daylit Area and Self-reported Frequency of Electric Lighting Use in Multi-dwelling Buildings
Published in LEUKOS, 2022
Due to the benefits of daylight, a considerable amount of standards, regulations and certification schemes include provisions for indoor daylight availability, e.g. EN17037 (CEN 2018). However, the potential to reduce residential electricity for lighting by means of daylight utilization has been challenged by previous work, stating that the use of artificial lighting seems to be largely independent from the availability of natural light, owing to individual occupant habits and preferences regarding electric lighting (Lobaccaro et al. 2019, 1). On the contrary, another study proposing daylight performance indicators for residential spaces assumed that good levels of daylight illuminances are likely to be associated with lower levels of electric lighting usage (Mardaljevic et al. 2011, 6). In the present study, it was hypothesized that daytime is a period when the sun and sky may provide adequate illumination for some domestic activities (e.g. cooking or cleaning), resulting in occupants switching on lights less frequently if their dwellings are adequately daylit. Behavioral aspects notwithstanding, the present paper aims to demonstrate that daytime electric lighting use in residential spaces is indeed associated with indoor daylight availability. In addition, the study aims to identify (if any) preference among occupants, with respect to which room function is (or is not) prioritized in terms of daylight availability.
Restricting short-wavelength light in the evening to improve sleep in recreational athletes – A pilot study
Published in European Journal of Sport Science, 2019
Melanie Knufinke, Lennart Fittkau-Koch, Els I. S. Møst, Michiel A. J. Kompier, Arne Nieuwenhuys
Sleep and wakefulness are regulated by two distinct process: a homeostatic process (Process S) that depicts increasing sleep pressure following sustained wakefulness, and a circadian process (Process C)(Borbely, 1982), which is regulated by the circadian system and requires periodic light–dark exposure for stable entrainment to the geographical day (Czeisler et al., 1986; Duffy & Wright, 2005). Specifically, information on environmental light is received by photoreceptors in the retina and, via non-image forming intrinsically photoreceptive retinal ganglion cells (ipRGC) (Brainard et al., 2001; Thapan, Arendt, & Skene, 2001), directly transmitted to the suprachiasmatic nucleus (SCN), the site of the circadian ‘master clock’. The SCN, in turn, sends information on circadian time to, for example, the pineal gland where melatonin is secreted in the evening, or suppressed in case of evening-light exposure (Brainard et al., 2001). Hence, the timing of light exposure is crucial: daytime light exposure facilitates the process of waking up and staying alert during the early day, while in the evening, the absence of light facilitates sleepiness.