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Source, Impact, and Perspective of Light Pollution
Published in Tuan Anh Nguyen, Ram K. Gupta, Nanotechnology for Light Pollution Reduction, 2023
Essia Hannachi, Yassine Slimani
At first, it was supposed that light of at minimum 2,500 lux was enough to adjust the excretion of melatonin by the human pineal gland. However, later studies proved that low illumination of blue light can considerably prevent the production of melatonin [7]. Two experiments were conducted in real-life, home settings on 33 youth volunteers. Young volunteers were exposed to 96 hours of 1 lux artificial light or 48 hours of 5 lux artificial light. Two tests in normal conditions have been performed by K. Stebelova et al. [8]. The results showed that subjects were more delicate to dim light in the whole night, as previously anticipated. Artificial light up to 5 lux decreased significantly the biosynthesis of melatonin and varied the quality of sleep as proved by an augmented proportion of 1 minute inactivity and a tendency to increase the index of fragmentation.
Introduction
Published in Agnieszka Wolska, Dariusz Sawicki, Małgorzata Tafil-Klawe, Visual and Non-Visual Effects of Light, 2020
Agnieszka Wolska, Dariusz Sawicki, Małgorzata Tafil-Klawe
Exposure to high intensity blue light can affect many physiological functions, and can even induce retina injuries or damage. This is why the blue light hazard arising from artificial sources must be evaluated and exposure levels at workers’ eye positions must be compared with exposure limit values for blue light hazard established by the International Commission on Non-Ionizing Radiation Protection (ICNIRP) and Directive 2006/25/EC of the European Parliament and of the Council. However, present-day knowledge about blue light can also be used to treat sleep disorders. In modern society, the use of blue light is becoming increasingly prominent. A large world population is exposed to artificial light at unusual times of the day or late at night. Light has a cumulative effect of many different characteristics (wavelength, intensity, duration of exposure, time of day). It is important to consider the spectral output of light sources for the improvement of alertness during night shifts, but also to minimize the danger associated with blue light and artificial light exposure.
Ethical Considerations in Engineering
Published in Diane P. Michelfelder, Neelke Doorn, The Routledge Handbook of the Philosophy of Engineering, 2020
So when the engineers at GM designed a mercury light switch for trunk lids, they introduced a welcome benefit—a light to see what is inside the trunk when the lid is opened. But they also introduced an unnecessary harm: mercury in vapor form is extremely toxic to our central nervous system, among other things. The harm they introduced was unnecessary because there were other ways to design a trunk light switch that did not require a toxic substance. We can also find necessary harms, features of design solutions that are likely to cause harm but are necessary to achieve the proper effects. Computer screens emit blue light. It is not possible to have computer screens without blue light emissions, but too much can cause macular degeneration.
Associations between psychological responses under artificial light environment and sleep activity
Published in Science and Technology for the Built Environment, 2023
Ting Cao, Li Lan, Zhiwei Lian, Jingyun Shen
Light acts as an environmental zeitgeber that synchronizes the day-night rhythm of the human body. However, the emergence of artificial light sources had a negative impact on the lifestyle (Peeters et al. 2021). According to Zhang, Cao, and Zhu (2018) field test into residents’ daily sleep environment, occupants seemed to adapt to the bedroom lights without any interference with their daily sleep activities. From the perspective of non-visual effects, previous studies found that melanotic equivalent daylight illuminance provided a robust predictor on human sleep (Cajochen et al. 2022; Brown et al. 2022) through an intensity-response function and circadian phase-shifts (Wagner 1996) based on different illuminations and wavelengths (Lockley, Brainard, and Czeisler 2003). Thus, a healthy lighting regime was considered crucial to improve sleep from the standpoint of illuminance, timing, duration, and correlated color temperature (Peeters et al. 2021). As for sleep, previous research showed that the composition of blue light might affect the suprachiasmatic nuclei by controlling the melatonin, leading to sleep delay and decline of sleep quality (Gooley et al. 2010; Chellappa et al. 2013). Direct exposure to low CCT light before bedtime resulted in better sleep quality for adolescents, decreased drowsiness the next morning, as well as slightly fatigue (Wen at al., 2021). And good sleep might benefit the recovery of energy and physical strength, and reduce the risk of mental and cardiovascular diseases (Opp 2009). Therefore, a study on use of artificial lights before sleep could be incredibly insightful.
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
Considering these limitations and gaps in the current literature, the present study investigated the effectiveness of blocking short-wavelength light in the evening on sleep under natural conditions in a non-sleep disordered and physically active population. Using a within-subject crossover design, recreational athletes were instructed to wear amber-lens glasses before bedtime in the experimental condition, which were substituted by non-vision adjusting transparent glasses in the control condition. In both conditions, sleep was monitored using wrist-worn actigraphy and daily sleep diaries for a period of nine nights. Considering the recent literature and the effects of short-wavelength light on the melatonin synthesis (Lockley, Brainard, & Czeisler, 2003), it was hypothesized that using blue-light blocking amber-lens glasses in the evening will improve actigraphy- and diary-based sleep onset latency, and potentially secondary measures such as total sleep time, sleep efficiency, and subjectively rated sleep quality.
Assessment of SARS-CoV-2 surrogate inactivation on surfaces and in air using UV and blue light-based intervention technologies
Published in Journal of the Air & Waste Management Association, 2023
Dilpreet Singh, Anand R. Soorneedi, Nachiket Vaze, Ron Domitrovic, Frank Sharp, Douglas Lindsey, Annette Rohr, Matthew D. Moore, Petros Koutrakis, Ed Nardell, Philip Demokritou
As shown in Figure 1, each individual device was held above the virus-inoculated surface (circular stainless-steel coupon, 1.82 cm diameter). The device was turned on and the appropriate UV/light meter was placed directly underneath at the location of the exposure coupons. For all four devices, the measurement of intensity was performed at the peak wavelength of the device. For UV measurement, a X1–5 optometer (Gigahertz-Optik, Amesbury MA) was utilized. For the measurement of blue light, the CSS-45 remote spectral detector (Gigahertz-Optik, Amesbury MA) was used. The UV/blue light irradiance measurement was conducted in triplicate and averaged. The measurement devices utilized were calibrated by the manufacturer against the appropriate standards and verified before operation.