Lighting

Last updated
Acropolis of Athens illuminated at night Acropolis Of Athens Greece 04.jpg
Acropolis of Athens illuminated at night
Illuminated cherry blossoms, light from the shop windows, and Japanese lantern at night in Ise, Mie, Japan Cherry blossoms with Isuzu-Chaya and Akafuku store at Night.jpg
Illuminated cherry blossoms, light from the shop windows, and Japanese lantern at night in Ise, Mie, Japan

Lighting or illumination is the deliberate use of light to achieve practical or aesthetic effects. Lighting includes the use of both artificial light sources like lamps and light fixtures, as well as natural illumination by capturing daylight. Daylighting (using windows, skylights, or light shelves) is sometimes used as the main source of light during daytime in buildings. This can save energy in place of using artificial lighting, which represents a major component of energy consumption in buildings. Proper lighting can enhance task performance, improve the appearance of an area, or have positive psychological effects on occupants.

Contents

Indoor lighting is usually accomplished using light fixtures, and is a key part of interior design. Lighting can also be an intrinsic component of landscape projects.

History

With the discovery of fire, the earliest form of artificial lighting used to illuminate an area were campfires or torches. As early as 400,000 years ago, fire was kindled in the caves of Peking Man. Prehistoric people used primitive oil lamps to illuminate surroundings. These lamps were made from naturally occurring materials such as rocks, shells, horns and stones, were filled with grease, and had a fiber wick. Lamps typically used animal or vegetable fats as fuel. Hundreds of these lamps (hollow worked stones) have been found in the Lascaux caves in modern-day France, dating to about 15,000 years ago. Oily animals (birds and fish) were also used as lamps after being threaded with a wick. Fireflies have been used as lighting sources. [1] Candles and glass and pottery lamps were also invented. [2] Chandeliers were an early form of "light fixture".

A major reduction in the cost of lighting occurred with the discovery of whale oil. [3] The use of whale oil declined after Abraham Gesner, a Canadian geologist, first refined kerosene in the 1840s, allowing brighter light to be produced at substantially lower cost. [4] In the 1850s, the price of whale oil dramatically increased (more than doubling from 1848 to 1856) due to shortages of available whales, hastening whale oil's decline. [4] By 1860, there were 33 kerosene plants in the United States, and Americans spent more on gas and kerosene than on whale oil. [4] The final death knell for whale oil was in 1859, when crude oil was discovered and the petroleum industry arose. [4]

Dim night lighting for the old warehouses along the river in the old town of Porvoo, Finland Finland, Porvoo, Old Town by night, Teemu Eskola.jpg
Dim night lighting for the old warehouses along the river in the old town of Porvoo, Finland

Gas lighting was economical enough to power street lights in major cities starting in the early 1800s, and was also used in some commercial buildings and in the homes of wealthy people. The gas mantle boosted the luminosity of utility lighting and of kerosene lanterns. The next major drop in price came about in the 1880s with the introduction of electric lighting in the form of arc lights for large space and street lighting, followed by incandescent light bulb-based utilities for indoor and outdoor lighting. [3] [5]

Over time, electric lighting became ubiquitous in developed countries. [6] Segmented sleep patterns disappeared, improved nighttime lighting made more activities possible at night, and more street lights reduced urban crime. [7] [8] [9]

Fixtures

Lighting fixtures come in a wide variety of styles for various functions. The most important functions are as a holder for the light source, to provide directed light and to avoid visual glare. [10] Some are very plain and functional, while some are pieces of art in themselves. Nearly any material can be used, so long as it can tolerate the excess heat and is in keeping with safety codes.

An important property of light fixtures is the luminous efficacy or wall-plug efficiency, meaning the amount of usable light emanating from the fixture per used energy, usually measured in lumen per watt. A fixture using replaceable light sources can also have its efficiency quoted as the percentage of light passed from the "bulb" to the surroundings. The more transparent the lighting fixtures are, the higher efficacy. Shading the light will normally decrease efficacy but increase the directionality and the visual comfort probability.

Color temperature for white light sources also affects their use for certain applications. The color temperature of a white light source is the temperature in kelvins of a theoretical black body emitter that most closely matches the spectral characteristics (spectral power distribution) of the lamp. An incandescent bulb has a color temperature around 2800 to 3000 kelvins; daylight is around 6400 kelvins. Lower color temperature lamps have relatively more energy in the yellow and red part of the visible spectrum, while high color temperatures correspond to lamps with more of a blue-white appearance. For critical inspection or color matching tasks, or for retail displays of food and clothing, the color temperature of the lamps will be selected for the best overall lighting effect.[ citation needed ]

Types

A demonstration of the effects of different kinds of lighting SameEyes4.jpg
A demonstration of the effects of different kinds of lighting

Lighting is classified by intended use as general, accent, or task lighting, depending largely on the distribution of the light produced by the fixture.

Methods

Forms of lighting

Indoor lighting

Wall-mounted light with shadows BWLight.jpg
Wall-mounted light with shadows

Forms of lighting include alcove lighting, which like most other uplighting is indirect. This is often done with fluorescent lighting (first available at the 1939 World's Fair) or rope light, occasionally with neon lighting, and recently with LED strip lighting. It is a form of backlighting.

Soffit or close to wall lighting can be general or a decorative wall-wash, sometimes used to bring out texture (like stucco or plaster) on a wall, though this may also show its defects as well. The effect depends heavily on the exact type of lighting source used.

Recessed lighting (often called "pot lights" in Canada, "can lights" or 'high hats" in the US) is popular, with fixtures mounted into the ceiling structure so as to appear flush with it. These downlights can use narrow beam spotlights, or wider-angle floodlights, both of which are bulbs having their own reflectors. There are also downlights with internal reflectors designed to accept common 'A' lamps (light bulbs) which are generally less costly than reflector lamps. Downlights can be incandescent, fluorescent, HID (high intensity discharge) or LED.

Track lighting, invented by Lightolier, [14] was popular at one period of time because it was much easier to install than recessed lighting, and individual fixtures are decorative and can be easily aimed at a wall. It has regained some popularity recently in low-voltage tracks, which often look nothing like their predecessors because they do not have the safety issues that line-voltage systems have, and are therefore less bulky and more ornamental in themselves. A master transformer feeds all of the fixtures on the track or rod with 12 or 24 volts, instead of each light fixture having its own line-to-low voltage transformer. There are traditional spots and floods, as well as other small hanging fixtures. A modified version of this is cable lighting, where lights are hung from or clipped to bare metal cables under tension.

A sconce is a wall-mounted fixture, particularly one that shines up and sometimes down as well. A torchère is an uplight intended for ambient lighting. It is typically a floor lamp but may be wall-mounted like a sconce. Further interior light fixtures include chandeliers, pendant lights, ceiling fans with lights, close-to-ceiling or flush lights, and various types of lamps [15]

The portable or table lamp is probably the most common fixture, found in many homes and offices. The standard lamp and shade that sits on a table is general lighting, while the desk lamp is considered task lighting. Magnifier lamps are also task lighting.

Animated fountain in Moscow's Square of Europe, lit at night Fountain Europe Square Moscow.jpg
Animated fountain in Moscow's Square of Europe, lit at night

The illuminated ceiling was once popular in the 1960s and 1970s but fell out of favor after the 1980s. This uses diffuser panels hung like a suspended ceiling below fluorescent lights, and is considered general lighting. Other forms include neon, which is not usually intended to illuminate anything else, but to actually be an artwork in itself. This would probably fall under accent lighting, though in a dark nightclub it could be considered general lighting.

In a movie theater, steps in the aisles are usually marked with a row of small lights for convenience and safety, when the film has started and the other lights are off. Traditionally made up of small low wattage, low-voltage lamps in a track or translucent tube, these are rapidly being replaced with LED based versions.

Outdoor lighting

High mast lighting along Highway 401 in Ontario, Canada Highway 401 Night Lapse Busy.jpg
High mast lighting along Highway 401 in Ontario, Canada

Street Lights are used to light roadways and walkways at night. Some manufacturers are designing LED and photovoltaic luminaires to provide an energy-efficient alternative to traditional street light fixtures. [16] [17] [18]

Floodlights are used to illuminate outdoor playing fields or work zones during nighttime. Floodlights.jpg
Floodlights are used to illuminate outdoor playing fields or work zones during nighttime.

Floodlights can be used to illuminate work zones [19] or outdoor playing fields during nighttime hours. [20] [21] The most common type of floodlights are metal halide and high pressure sodium lights.

Beacon lights are positioned at the intersection of two roads to aid in navigation.

Sometimes security lighting can be used along roadways in urban areas, or behind homes or commercial facilities. These are extremely bright lights used to deter crime. Security lights may include floodlights and be activated with PIR switches that detect moving heat sources in darkness.

Entry lights can be used outside to illuminate and signal the entrance to a property. [22] These lights are installed for safety, security, and for decoration.

The decks and gangway of tugboat Samuel de Champlain illuminated at night while docked at a shipyard for the purposes of safety and security SDC Lit at Night.jpg
The decks and gangway of tugboat Samuel de Champlain illuminated at night while docked at a shipyard for the purposes of safety and security

Underwater accent lighting is also used for koi ponds, fountains, swimming pools and the like.

Neon signs are most often used to attract attention rather than to illuminate.

Vehicle use

Vehicles typically include headlamps and tail lights. Headlamps are white or selective yellow lights placed in the front of the vehicle, designed to illuminate the upcoming road and to make the vehicle more visible. Many manufactures are turning to LED headlights as an energy-efficient alternative to traditional headlamps. [23] Tail and brake lights are red and emit light to the rear so as to reveal the vehicle's direction of travel to following drivers. White rear-facing reversing lamps indicate that the vehicle's transmission has been placed in the reverse gear, warning anyone behind the vehicle that it is moving backwards, or about to do so. Flashing turn signals on the front, side, and rear of the vehicle indicate an intended change of position or direction. In the late 1950s, some automakers began to use electroluminescent technology to backlight their cars' speedometers and other gauges or to draw attention to logos or other decorative elements.

Lamps

Commonly called 'light bulbs', lamps are the removable and replaceable part of a light fixture, which converts electrical energy into electromagnetic radiation. While lamps have traditionally been rated and marketed primarily in terms of their power consumption, expressed in watts, proliferation of lighting technology beyond the incandescent light bulb has eliminated the correspondence of wattage to the amount of light produced. For example, a 60 W incandescent light bulb produces about the same amount of light as a 13 W compact fluorescent lamp. Each of these technologies has a different efficacy in converting electrical energy to visible light. Visible light output is typically measured in lumens. This unit only quantifies the visible radiation, and excludes invisible infrared and ultraviolet light. A wax candle produces on the close order of 13 lumens, a 60 watt incandescent lamp makes around 700 lumens, and a 15-watt compact fluorescent lamp produces about 800 lumens, but actual output varies by specific design. [24] Rating and marketing emphasis is shifting away from wattage and towards lumen output, to give the purchaser a directly applicable basis upon which to select a lamp.


Lamp types include:

Design and architecture

Architectural lighting design

Lighting without windows: The Pantheon in the 18th century, painted by Giovanni Paolo Panini. Giovanni Paolo Panini - Interior of the Pantheon, Rome - Google Art Project.jpg
Lighting without windows: The Pantheon in the 18th century, painted by Giovanni Paolo Panini.

Lighting design as it applies to the built environment is known as 'architectural lighting design'. Lighting of structures considers aesthetic elements as well as practical considerations of quantity of light required, occupants of the structure, energy efficiency, and cost. Artificial lighting takes into account the amount of daylight received in a space by using daylight factor calculations. For simple installations, hand calculations based on tabular data are used to provide an acceptable lighting design. More critical or complex designs now routinely use computer software such as Radiance [29] for mathematical modeling, which can allow an architect to quickly and accurately evaluate the benefit of a proposed design.

In some instances, the materials used on walls and furniture play a key role in the lighting effect. For example, dark paint tends to absorb light, making the room appear smaller and more dim than it is, whereas light paint does the opposite. Other reflective surfaces also have an effect on lighting design. [13] [30]

On stage and set

Lighting and shadows Female in red pullover and blue jeans -coloured lights-2Nov2003.jpg
Lighting and shadows
Moving heads in a photo studio set Ivan-rogue-hybrid.jpg
Moving heads in a photo studio set
Illuminating a subject from beneath can create a heightened dramatic effect. ScaryVampire.JPG
Illuminating a subject from beneath can create a heightened dramatic effect.

Lighting illuminates the performers and artists in a live theatre, dance, or musical performance, and is selected and arranged to create dramatic effects. Stage lighting uses general illumination technology in devices configured for easy adjustment of their output characteristics.[ citation needed ] The setup of stage lighting is tailored for each scene of each production. Dimmers, colored filters, reflectors, lenses, motorized or manually aimed lamps, and different kinds of flood and spot lights are among the tools used by a stage lighting designer to produce the desired effects. A set of lighting cues are prepared so that the lighting operator can control the lights in step with the performance; complex theatre lighting systems use computer control of lighting instruments.

Motion picture and television production use many of the same tools and methods of stage lighting. Especially in the early days of these industries, very high light levels were required and heat produced by lighting equipment presented substantial challenges. Modern cameras require less light, and modern light sources emit less heat.

Measurement

Measurement of light or photometry is generally concerned with the amount of useful light falling on a surface and the amount of light emerging from a lamp or other source, along with the colors that can be rendered by this light. The human eye responds differently to light from different parts of the visible spectrum, therefore photometric measurements must take the luminosity function into account when measuring the amount of useful light. The basic SI unit of measurement is the candela (cd), which describes the luminous intensity, all other photometric units are derived from the candela. Luminance for instance is a measure of the density of luminous intensity in a given direction. It describes the amount of light that passes through or is emitted from a particular area, and falls within a given solid angle. The SI unit for luminance is candela per square metre (cd/m2). The CGS unit of luminance is the stilb, which is equal to one candela per square centimetre or 10 kcd/m2. The amount of useful light emitted from a source or the luminous flux is measured in lumen (lm).

The SI unit of illuminance and luminous emittance, being the luminous power per area, is measured in Lux. It is used in photometry as a measure of the intensity, as perceived by the human eye, of light that hits or passes through a surface. It is analogous to the radiometric unit watts per square metre, but with the power at each wavelength weighted according to the luminosity function, a standardized model of human visual brightness perception. In English, "lux" is used in both singular and plural. [31]

Visual comfort often entails the measurement of subjective evaluations. [32] Several measurement methods have been developed to control glare resulting from indoor lighting design. The Unified Glare Rating (UGR), the Visual Comfort Probability, and the Daylight Glare Index are some of the most well-known methods of measurement. In addition to these new methods, four main factors influence the degree of discomfort glare; the luminance of the glare source, the solid angle of the glare source, the background luminance, and the position of the glare source in the field of view must all be taken into account. [12] [33]

Color properties

The Leppavaaran Torni building in Leppavaara, Espoo, Finland, illuminated with colorful lights in 2017 Leppavaaran Torni illuminated 1.jpg
The Leppävaaran Torni building in Leppävaara, Espoo, Finland, illuminated with colorful lights in 2017

To define light source color properties, the lighting industry predominantly relies on two metrics, correlated color temperature (CCT), commonly used as an indication of the apparent "warmth" or "coolness" of the light emitted by a source, and color rendering index (CRI), an indication of the light source's ability to make objects appear natural.

However, these two metrics, developed in the last century, are facing increased challenges and criticisms as new types of light sources, particularly light-emitting diodes (LEDs), become more prevalent in the market.

For example, in order to meet the expectations for good color rendering in retail applications, research [34] suggests using the well-established CRI along with another metric called gamut area index (GAI). GAI represents the relative separation of object colors illuminated by a light source; the greater the GAI, the greater the apparent saturation or vividness of the object colors. As a result, light sources which balance both CRI and GAI are generally preferred over ones that have only high CRI or only high GAI. [35]

Light exposure

Typical measurements of light have used a Dosimeter. Dosimeters measure an individual's or an object's exposure to something in the environment, such as light dosimeters and ultraviolet dosimeters.

In order to specifically measure the amount of light entering the eye, personal circadian light meter called the Daysimeter has been developed. [36] This is the first device created to accurately measure and characterize light (intensity, spectrum, timing, and duration) entering the eye that affects the human body's clock.

The small, head-mounted device measures an individual's daily rest and activity patterns, as well as exposure to short-wavelength light that stimulates the circadian system. The device measures activity and light together at regular time intervals and electronically stores and logs its operating temperature. The Daysimeter can gather data for up to 30 days for analysis. [37]

Energy consumption

Several strategies are available to minimize energy requirements for lighting a building:

Specification of illumination requirements is the basic concept of deciding how much illumination is required for a given task. Clearly, much less light is required to illuminate a hallway compared to that needed for a word processing work station. Generally speaking, the energy expended is proportional to the design illumination level. For example, a lighting level of 400 lux might be chosen for a work environment involving meeting rooms and conferences, whereas a level of 80 lux could be selected for building hallways. [39] [40] [41] [42] [43] If the hallway standard simply emulates the conference room needs, then much more energy will be consumed than is needed.

Lighting control systems

Lighting control systems reduce energy usage and cost by helping to provide light only when and where it is needed. Lighting control systems typically incorporate the use of time schedules, occupancy control, and photocell control (i.e. daylight harvesting). Some systems also support demand response and will automatically dim or turn off lights to take advantage of utility incentives. Lighting control systems are sometimes incorporated into larger building automation systems.

Many newer control systems are using wireless mesh open standards (such as Zigbee), [44] which provides benefits including easier installation (no need to run control wires) and interoperability with other standards-based building control systems (e.g. security). [45]

In response to daylighting technology, daylight harvesting systems have been developed to further reduce energy consumption. These technologies are helpful, but they do have their downfalls. Many times, rapid and frequent switching of the lights on and off can occur, particularly during unstable weather conditions or when daylight levels are changing around the switching illuminance. Not only does this disturb occupants, it can also reduce lamp life. A variation of this technology is the 'differential switching or dead-band' photoelectric control which has multiple illuminances it switches from so as not to disturb occupants as much. [11] [46]

Occupancy sensors to allow operation for whenever someone is within the area being scanned can control lighting. When motion can no longer be detected, the lights shut off. Passive infrared sensors react to changes in heat, such as the pattern created by a moving person. The control must have an unobstructed view of the building area being scanned. Doors, partitions, stairways, etc. will block motion detection and reduce its effectiveness. The best applications for passive infrared occupancy sensors are open spaces with a clear view of the area being scanned. Ultrasonic sensors transmit sound above the range of human hearing and monitor the time it takes for the sound waves to return. A break in the pattern caused by any motion in the area triggers the control. Ultrasonic sensors can see around obstructions and are best for areas with cabinets and shelving, restrooms, and open areas requiring 360-degree coverage. Some occupancy sensors utilize both passive infrared and ultrasonic technology, but are usually more expensive. They can be used to control one lamp, one fixture or many fixtures. [47] [48]

Daylighting

Daylight used at the train station Gare de l'Est Paris Gare de l'Est Paris 2007 033.jpg
Daylight used at the train station Gare de l'Est Paris

Daylighting is the oldest method of interior lighting. Daylighting is simply designing a space to use as much natural light as possible. This decreases energy consumption and costs, and requires less heating and cooling from the building. Daylighting has also been proven to have positive effects on patients in hospitals as well as work and school performance. Due to a lack of information that indicate the likely energy savings, daylighting schemes are not yet popular among most buildings. [11] [49] Unlike electric lighting, the distribution of daylight varies considerably throughout the entire year inside a building. [50]

Solid-state lighting

In recent years light-emitting diodes (LEDs) are becoming increasingly efficient leading to an extraordinary increase in the use of solid state lighting. In many situations, controlling the light emission of LEDs may be done most effectively by using the principles of nonimaging optics. [51]

Health effects

It is valuable to provide the correct light intensity and color spectrum for each task or environment. Otherwise, energy not only could be wasted but over-illumination can lead to adverse health and psychological effects.

Beyond the energy factors being considered, it is important not to over-design illumination, lest adverse health effects such as headache frequency, stress, and increased blood pressure be induced by the higher lighting levels. In addition, glare or excess light can decrease worker efficiency. [52]

Analysis of lighting quality particularly emphasizes use of natural lighting, but also considers spectral content if artificial light is to be used. Not only will greater reliance on natural light reduce energy consumption, but will favorably impact human health and performance. New studies have shown that the performance of students is influenced by the time and duration of daylight in their regular schedules. Designing school facilities to incorporate the right types of light at the right time of day for the right duration may improve student performance and well-being. Similarly, designing lighting systems that maximize the right amount of light at the appropriate time of day for the elderly may help relieve symptoms of Alzheimer's disease. The human circadian system is entrained to a 24-hour light-dark pattern that mimics the earth's natural light/dark pattern. When those patterns are disrupted, they disrupt the natural circadian cycle. Circadian disruption may lead to numerous health problems including breast cancer, seasonal affective disorder, delayed sleep phase syndrome, and other ailments. [53] [54]

A study conducted in 1972 and 1981, documented by Robert Ulrich, surveyed 23 surgical patients assigned to rooms looking out on a natural scene. The study concluded that patients assigned to rooms with windows allowing much natural light had shorter postoperative hospital stays, received fewer negative evaluative comments in nurses' notes, and took fewer potent analgesics than 23 matched patients in similar rooms with windows facing a brick wall. This study suggests that due to the nature of the scenery and daylight exposure was indeed healthier for patients as opposed to those exposed to little light from the brick wall. In addition to increased work performance, proper usage of windows and daylighting crosses the boundaries between pure aesthetics and overall health. [49] [55]

Alison Jing Xu, assistant professor of management at the University of Toronto Scarborough and Aparna Labroo of Northwestern University conducted a series of studies analyzing the correlation between lighting and human emotion. The researchers asked participants to rate a number of things such as: the spiciness of chicken-wing sauce, the aggressiveness of a fictional character, how attractive someone was, their feelings about specific words, and the taste of two juices–all under different lighting conditions. In their study, they found that both positive and negative human emotions are felt more intensely in bright light. Professor Xu stated, "we found that on sunny days depression-prone people actually become more depressed." They also found that dim light makes people make more rational decisions and settle negotiations easier. In the dark, emotions are slightly suppressed. However, emotions are intensified in the bright light. [56] [57] [58]

Environmental issues

Compact fluorescent lamps

Compact fluorescent lamps (CFLs) use less power than an incandescent lamp to supply the same amount of light, however they contain mercury which is a disposal hazard. Due to the ability to reduce electricity consumption, many organizations encouraged the adoption of CFLs. Some electric utilities and local governments subsidized CFLs or provided them free to customers as a means of reducing electricity demand. For a given light output, CFLs use between one fifth and one quarter the power of an equivalent incandescent lamp. Unlike incandescent lamps CFLs need a little time to warm up and reach full brightness. Not all CFLs are suitable for dimming. CFL's have largely been replaced with LED technologies.

LED lamps

LED lamps provide significant energy savings over incandescent and fluorescent lamps. [59] According to the Energy Saving Trust, LED lamps use only 10% power compared to a standard incandescent bulb, where compact fluorescent lamps use 20% and energy saving halogen lamps 70%. The lifetime is also much longer — up to 50,000 hours. The downside when they were first popularized was the initial cost. By 2018, production costs dropped, performance increased, and energy consumption was reduced. While the initially cost of LEDs is still higher than incandescent lamps, the savings are so dramatic that there are very few instances that LEDs are not the most economical choice.

Scattered light from outdoor illumination may have effects on the environment and human health. [60] For instance, one study conducted by the American Medical Association [61] warned on the use of high blue content white LEDs in street lighting, due to their higher impact on human health and environment, compared to low blue content light sources (e.g. High Pressure Sodium, phosphor-coated or PC amber LEDs, and low CCT LEDs).

Light pollution

Light pollution is a growing problem in reaction to excess light being given off by numerous signs, houses, and buildings. Polluting light is often wasted light involving unnecessary energy costs and carbon dioxide emissions. Light pollution is described as artificial light that is excessive or intrudes where it is not wanted. Well-designed lighting sends light only where it is needed without scattering it elsewhere. Poorly designed lighting can also compromise safety. For example, glare creates safety issues around buildings by causing very sharp shadows, temporarily blinding passersby making them vulnerable to would-be assailants. [62] [63] The negative ecological effects of artificial light have been increasingly well documented. [64] [65] The World Health Organization in 2007 [66] issued a report that noted the effects of bright light on flora and fauna, sea turtle hatchlings, frogs during mating season and the migratory patterns of birds. The American Medical Association in 2012 [67] issued a warning that extended exposure to light at night increases the risk of some cancers. [60] Two studies in Israel from 2008 have yielded some additional findings about a possible correlation between artificial light at night and certain cancers. [68]

Effects on animals

Moths circling an electric lightbulb Moth near lamp (cropped).jpg
Moths circling an electric lightbulb

Artificial light at night refers to any light source other than a natural light source. Sources of artificial light include LEDS and fluorescents. This particular light source has effect on the reproduction, immune function, metabolism, thermoregulation and body temperature of organisms that need light for their daily activity.

Firstly, most organisms metabolism largely depends on light. In some instances the presence of intense light starts up or increases enzyme activity inside the body of an animal. For diurnal organisms, high rate of metabolism takes place during the day and reduces or comes to a stop during the night thus, artificial light at night has a negative impact of the metabolism of diurnal organisms. Moreover, the body temperature of diurnal animals fall during the night but the presence of artificial light at night, then causes an increase in body temperature which affects the melatonin levels of the animal.

Furthermore, for organisms such as birds, their sex organs are activated in relation to light intensity in certain periods during the summer at day time to aid reproduction. These sex organs are deactivated during the night but the presence of artificial light during the night sometimes disrupts their reproduction process.

Professional organizations

International

The International Commission on Illumination (CIE) is an international authority and standard defining organization on color and lighting. Publishing widely used standard metrics such as various CIE color spaces and the color rendering index.

The Illuminating Engineering Society (IES), in conjunction with organizations like ANSI and ASHRAE, publishes guidelines, standards, and handbooks that allow categorization of the illumination needs of different built environments. Manufacturers of lighting equipment publish photometric data for their products, which defines the distribution of light released by a specific luminaire. This data is typically expressed in standardized form defined by the IESNA.

The International Association of Lighting Designers (IALD) is an organization which focuses on the advancement of lighting design education and the recognition of independent professional lighting designers. Those fully independent designers who meet the requirements for professional membership in the association typically append the abbreviation IALD to their name.

The Professional Lighting Designers Association (PLDA), formerly known as ELDA is an organisation focusing on the promotion of the profession of Architectural Lighting Design. They publish a monthly newsletter and organise different events throughout the world.

The National Council on Qualifications for the Lighting Professions (NCQLP) offers the Lighting Certification Examination which tests rudimentary lighting design principles. Individuals who pass this exam become "Lighting Certified" and may append the abbreviation LC to their name. This certification process is one of three national (U.S.) examinations (the others are CLEP and CLMC) in the lighting industry and is open not only to designers, but to lighting equipment manufacturers, electric utility employees, etc.

The Professional Lighting And Sound Association (PLASA) is a UK-based trade organisation representing the 500+ individual and corporate members drawn from the technical services sector. Its members include manufacturers and distributors of stage and entertainment lighting, sound, rigging and similar products and services, and affiliated professionals in the area. They lobby for and represent the interests of the industry at various levels, interacting with government and regulating bodies and presenting the case for the entertainment industry. Example subjects of this representation include the ongoing review of radio frequencies (which may or may not affect the radio bands in which wireless microphones and other devices use) and engaging with the issues surrounding the introduction of the RoHS (Restriction of Hazardous Substances Directive) regulations.

National

See also

Inventors

Lists

Related Research Articles

<span class="mw-page-title-main">Color temperature</span> Property of light sources related to black-body radiation

Color temperature is a parameter describing the color of a visible light source by comparing it to the color of light emitted by an idealized opaque, non-reflective body. The temperature of the ideal emitter that matches the color most closely is defined as the color temperature of the original visible light source. The color temperature scale describes only the color of light emitted by a light source, which may actually be at a different temperature.

<span class="mw-page-title-main">Electric light</span> Device for producing light from electricity

An electric light, lamp, or light bulb is an electrical component that produces light. It is the most common form of artificial lighting. Lamps usually have a base made of ceramic, metal, glass, or plastic which secures the lamp in the socket of a light fixture, which is often called a "lamp" as well. The electrical connection to the socket may be made with a screw-thread base, two metal pins, two metal caps or a bayonet mount.

<span class="mw-page-title-main">Daylighting (architecture)</span> Practice of placing openings and reflective surfaces so that sunlight can provide internal lighting

Daylighting is the practice of placing windows, skylights, other openings, and reflective surfaces so that direct or indirect sunlight can provide effective internal lighting. Particular attention is given to daylighting while designing a building when the aim is to maximize visual comfort or to reduce energy use. Energy savings can be achieved from the reduced use of artificial (electric) lighting or from passive solar heating. Artificial lighting energy use can be reduced by simply installing fewer electric lights where daylight is present or by automatically dimming or switching off electric lights in response to the presence of daylight – a process known as daylight harvesting.

<span class="mw-page-title-main">Fluorescent lamp</span> Lamp using fluorescence to produce light

A fluorescent lamp, or fluorescent tube, is a low-pressure mercury-vapor gas-discharge lamp that uses fluorescence to produce visible light. An electric current in the gas excites mercury vapor, to produce ultraviolet and make a phosphor coating in the lamp glow. Fluorescent lamps convert electrical energy into useful light much more efficiently than incandescent lamps, but are less efficient than most LED lamps. The typical luminous efficacy of fluorescent lamps is 50–100 lumens per watt, several times the efficacy of incandescent bulbs with comparable light output.

<span class="mw-page-title-main">Blacklight</span> Light fixture that emits long-wave ultraviolet light and very little visible light

A blacklight, also called a UV-A light, Wood's lamp, or ultraviolet light, is a lamp that emits long-wave (UV-A) ultraviolet light and very little visible light. One type of lamp has a violet filter material, either on the bulb or in a separate glass filter in the lamp housing, which blocks most visible light and allows through UV, so the lamp has a dim violet glow when operating. Blacklight lamps which have this filter have a lighting industry designation that includes the letters "BLB". This stands for "blacklight blue". A second type of lamp produces ultraviolet but does not have the filter material, so it produces more visible light and has a blue color when operating. These tubes are made for use in "bug zapper" insect traps, and are identified by the industry designation "BL". This stands for "blacklight".

<span class="mw-page-title-main">Compact fluorescent lamp</span> Fluorescent lamps with folded tubes, often with built-in ballast

A compact fluorescent lamp (CFL), also called compact fluorescent light, energy-saving light and compact fluorescent tube, is a fluorescent lamp designed to replace an incandescent light bulb; some types fit into light fixtures designed for incandescent bulbs. The lamps use a tube that is curved or folded to fit into the space of an incandescent bulb, and a compact electronic ballast in the base of the lamp.

<span class="mw-page-title-main">Emergency light</span> Backup light source used in power outages

An emergency light is a battery-backed lighting device that switches on automatically when a building experiences a power outage.

<span class="mw-page-title-main">Architectural lighting design</span> Field within architecture, interior design and electrical engineering

Architectural lighting design is a field of work or study that is concerned with the design of lighting systems within the built environment, both interior and exterior. It can include manipulation and design of both daylight and electric light or both, to serve human needs.

<span class="mw-page-title-main">Sulfur lamp</span> Lighting system

The sulfur lamp is a highly efficient full-spectrum electrodeless lighting system whose light is generated by sulfur plasma that has been excited by microwave radiation. They are a particular type of plasma lamp, and one of the most modern. The technology was developed in the early 1990s and appeared promising, but was not a commercial success by the late 1990s. Since 2005, lamps are again being manufactured for commercial use.

<span class="mw-page-title-main">Full-spectrum light</span> Light with frequencies ranging from infrared to near-ultraviolet

Full-spectrum light is light that covers the electromagnetic spectrum from infrared to near-ultraviolet, or all wavelengths that are useful to plant or animal life; in particular, sunlight is considered full spectrum, even though the solar spectral distribution reaching Earth changes with time of day, latitude, and atmospheric conditions.

<span class="mw-page-title-main">Light fixture</span> Electrical device with an electric lamp

A light fixture, light fitting, or luminaire is an electrical lighting device containing one or more light sources, such as lamps, and all the accessory components required for its operation to provide illumination to the environment. All light fixtures have a fixture body and one or more lamps. The lamps may be in sockets for easy replacement—or, in the case of some LED fixtures, hard-wired in place.

<span class="mw-page-title-main">Solid-state lighting</span> Lighting technology

Solid-state lighting (SSL) is a type of lighting that uses semiconductor light-emitting diodes (LEDs), organic light-emitting diodes (OLED), or polymer light-emitting diodes (PLED) as sources of illumination rather than electrical filaments, plasma, or gas.

<span class="mw-page-title-main">Lighting control system</span> Intelligent network based lighting control

A lighting control system is intelligent network-based lighting control that incorporates communication between various system inputs and outputs related to lighting control with the use of one or more central computing devices. Lighting control systems are widely used on both indoor and outdoor lighting of commercial, industrial, and residential spaces. Lighting control systems are sometimes referred to under the term smart lighting. Lighting control systems serve to provide the right amount of light where and when it is needed.

<span class="mw-page-title-main">Stage lighting instrument</span> Device that emits light to illuminate performers

Stage lighting instruments are used in stage lighting to illuminate theatrical productions, concerts, and other performances taking place in live performance venues. They are also used to light television studios and sound stages.

<span class="mw-page-title-main">Grow light</span> Lighting to aid plant growth

A grow light is an electric light that can help plants grow. Grow lights either attempt to provide a light spectrum similar to that of the sun, or to provide a spectrum that is more tailored to the needs of the plants being cultivated. Outdoor conditions are mimicked with varying colour temperatures and spectral outputs from the grow light, as well as varying the intensity of the lamps. Depending on the type of plant being cultivated, the stage of cultivation, and the photoperiod required by the plants, specific ranges of spectrum, luminous efficacy and color temperature are desirable for use with specific plants and time periods.

<span class="mw-page-title-main">LED lamp</span> Electric light that produces light using LEDs

An LED lamp or LED light is an electric light that produces light using light-emitting diodes (LEDs). LED lamps are significantly more energy-efficient than equivalent incandescent lamps and fluorescent lamps. The most efficient commercially available LED lamps have efficiencies exceeding 200 lumens per watt (lm/W) and convert more than half the input power into light. Commercial LED lamps have a lifespan several times longer than both incandescent and fluorescent lamps.

Aquarium lighting describes any type of artificial lighting that is used to illuminate an aquarium. Some types of aquaria such as reef aquariums and planted aquariums require specialized high intensity lighting to support photosynthetic life within the tank.

<span class="mw-page-title-main">LED street light</span> Type of lighting fixture

An LED street light or road light is an integrated light-emitting diode (LED) light fixture that is used for street lighting.

Electron-stimulated luminescence (ESL) is production of light by cathodoluminescence, i.e. by a beam of electrons made to hit a fluorescent phosphor surface. This is also the method used to produce light in a cathode ray tube (CRT). Experimental light bulbs that were made using this technology do not include magnetic or electrostatic means to deflect the electron beam.

United States Lighting Energy Policy is moving towards increased efficiency in order to lower greenhouse gas emissions and energy use. Lighting efficiency improvements in the United States can be seen through different standards and acts. The Energy Independence and Security Act of 2007 laid out changes in lighting legislation for the United States. This set up performance standards and the phase-out of incandescent light bulbs in order to require the use of more efficient fluorescent lighting. EISA 2007 is an effort to increase lighting efficiency by 25-30%. Opposition to EISA 2007 is demonstrated by the Better Use of Light Bulbs Act and the Light Bulb Freedom of Choice Act. The efforts to increase lighting efficiency are also demonstrated by the Energy Star program and the increase efficiency goals by 2011 and 2013. A ban on the manufacture and sale of most general purpose incandescent bulbs in the U.S. took effect on August 1, 2023.

References

  1. ↑ "Oil-Lamps and Candles". Notes and Queries. 1940-01-06. doi:10.1093/notesj/178.1.13-b. ISSN   1471-6941.
  2. ↑ Williams, Ben (1999). "A History of Light and Lighting". Archived from the original on 25 January 2013. Retrieved 23 November 2012.
  3. 1 2 "The History of Light". Planet Money. Episode 534. NPR. April 25, 2014. Retrieved June 20, 2016.
  4. 1 2 3 4 Eric Jay Dolin (2007). Leviathan: The History of Whaling in America. W.W. Norton & Co. pp. 339–40.
  5. ↑ The First Form of Electric Light History of the Carbon Arc Lamp (1800 - 1980s)'.Edison Tech Center, edisontechcenter.org
  6. ↑ James L. Kirtley (5 July 2011). Electric Power Principles: Sources, Conversion, Distribution and Use. John Wiley & Sons. pp. 11–. ISBN   978-1-119-95744-7.
  7. ↑ Vito, Gennaro F.; Maahs, Jeffrey R. (2011). Criminology: Theory, Research, and Policy (revised ed.). Jones & Bartlett. p.  70. ISBN   9780763766658.
  8. ↑ Felson, Marcus; Boba, Rachel L. (2009). Crime and Everyday Life. SAGE. p. 186. ISBN   9781483342658.
  9. ↑ Street lighting, energy conservation and crime. United States Law Enforcement Assistance Administration, Emergency Energy Committee, U.S. Dept. of Justice. 1974. The public [has] a general feeling that street lights have a deterrent effect on street crimes. This effect is somewhat substantiated by research conducted by LEAA and by the fact that various communities which have installed improved street lighting in certain areas have reported reductions in the rate of street crime.
  10. ↑ Kent, Michael; Fotios, Steve; Altomonte, Sergio (2019). "An Experimental Study on the Effect of Visual Tasks on Discomfort Due to Peripheral Glare". LEUKOS. 15 (1): 17–28. doi: 10.1080/15502724.2018.1489282 .
  11. 1 2 3 Li, D; Cheung, K; Wong, S; Lam, T (2010). "An analysis of energy-efficient light fittings and lighting controls". Applied Energy. 87 (2): 558–567. Bibcode:2010ApEn...87..558L. doi:10.1016/j.apenergy.2009.07.002.
  12. 1 2 Kim, W; Han, H; Kim, J (2009). "The position index of a glare source at the borderline between comfort and discomfort (BCD) in the whole visual field". Building & Environment. 44 (5): 1017–1023. Bibcode:2009BuEnv..44.1017K. doi:10.1016/j.buildenv.2008.07.007.
  13. 1 2 Velds, M. (2002). "User acceptance studies to evaluate discomfort glare in daylit room". Solar Energy. 73 (2): 95–103. Bibcode:2002SoEn...73...95V. doi:10.1016/s0038-092x(02)00037-3.
  14. ↑ Bernstein (2006). The New York Times Practical Guide to Practically Everything: The Essential Companion for Everyday Life . St. Martin's Press. pp.  424. ISBN   978-0312353889.
  15. ↑ West, Paul (June 1, 2018). "Living Room Lighting: 20 Powerful Ideas to Improve your Lighting". Lamps USA. Archived from the original on Feb 3, 2019. Retrieved 6 June 2018.
  16. ↑ "Post-Top Photovoltaic Pathway Luminaire" (PDF). Field Test DELTA. Iss. 4. Lighting Research Center. October 2009. Archived from the original (PDF) on 2010-12-04. Retrieved 2010-10-16.
  17. ↑ "LED Street Lighting" (PDF). Field Test DELTA Snapshot. Iss. 4. Lighting Research Center. March 2010. Archived from the original (PDF) on May 9, 2010. Retrieved 13 April 2010.
  18. ↑ "Photovoltaic Lighting - Introduction". NLPIP Lighting Answers. 9 (3). Lighting Research Center. July 2006. Archived from the original on Jun 11, 2010. Retrieved 13 April 2010.
  19. ↑ Transportation, Department of; Administration, Federal Highway (November 2003). Manual on Uniform Traffic Control Devices: Inserts Only. Claitor's Law Books and Publishing. ISBN   9781579809294.
  20. ↑ Draft Revised Environmental Impact Report for Scotts Valley High School--Glenwood Site. Denise Duffy & Associates. 1997.
  21. ↑ Felber, Bill; Fimoff, Mark; Levin, Len; Mancuso, Peter (April 2013). Inventing Baseball: The 100 Greatest Games that Shaped the 19th Century. SABR. ISBN   9781933599427.
  22. ↑ DELTA Snapshot: Outdoor Entry Lighting. Issue 11. Lighting Research Center. Found online at: http://www.lrc.rpi.edu/programs/delta/pdf/OutdoorEntry.pdf [last accessed 13 April 2010]
  23. ↑ Van Derlofske, J, JD Bullough, J Watkinson. 2005. Spectral Effects of LED Forward Lighting. TLA 2005-02. Lighting Research Center. Found online at: http://www.lrc.rpi.edu/programs/transportation/TLA/pdf/TLA-2005-02.pdf [last accessed 13 April 2010]
  24. ↑ Roger Fouquet, Heat, power and light: revolutions in energy services, Edward Elgar Publishing, 2008 ISBN   1-84542-660-6, page 411
  25. ↑ "Leading luminaries". Cabinet Maker. 5419: 21–22. 2004.
  26. ↑ Khan N, Abas N. Comparative study of energy saving light sources. Renewable & Sustainable Energy Reviews [serial online].
  27. ↑ "How to power an ENERGY-EFFICIENT LIGHT". Machine Design. 80 (12): 51–53. 2008.
  28. ↑ Another view of the interior by Panini (1735), Liechtenstein Museum, Vienna Archived 2011-09-28 at the Wayback Machine
  29. ↑ "Radiance". Energy.gov. Retrieved 2024-08-27.
  30. ↑ Israel, C; Bleeker, N (2008). "Sustainable Lighting Strategies". Electrical Wholesaling. 89 (9): 38–41.
  31. ↑ NIST Guide to SI Units - 9 Rules and Style Conventions for Spelling Unit Names, National Institute of Standards and Technology
  32. ↑ Fotios, Steve; Kent, Michael (2021). "Measuring Discomfort from Glare: Recommendations for Good Practice". LEUKOS. 17 (4): 338–358. doi:10.1080/15502724.2020.1803082. S2CID   225293753 . Retrieved 2021-11-01.
  33. ↑ W. Kim and Y. Koga, "Effect of local background luminance on discomfort glare, Building Environ 2004; 38, pp.
  34. ↑ ASSIST recommends: Guide to Light and Color in Retail Merchandising. 2010. Volume 8, Issue 1. Available online at: "ASSIST recommends: Light Source Color for Retail Merchandising | ASSIST Program | Solid State Lighting | Programs | LRC". Archived from the original on 2011-07-18. Retrieved 2011-05-13.
  35. ↑ ASSIST recommends: Recommendations for Specifying Color Properties of Light Sources for Retail Merchandising. 2010. Volume 8, Issue 2. Available online at: "ASSIST recommends: Light Source Color for Retail Merchandising | ASSIST Program | Solid State Lighting | Programs | LRC". Archived from the original on 2011-07-18. Retrieved 2011-05-13.
  36. ↑ Rea, MS; Bierman, A; Figueiro, MG; Bullough, JD (2008). "A new approach to understanding the impact of circadian disruption on human health". J Circadian Rhythms. 6: 7. doi: 10.1186/1740-3391-6-7 . PMC   2430544 . PMID   18510756.
  37. ↑ Lighting Research Center Website: New approach sheds light on ways circadian disruption affects human health. Found online at: "Light and Health | Research Programs | LRC". Archived from the original on 2010-06-09. Retrieved 2016-02-07. [last accessed 13 April 2010]
  38. ↑ The Guardian newspaper: Alfredo Moser: Bottle light inventor proud to be poor, 13 August 2013
  39. ↑ Australian Greenhouse Office (May 2005). "Chapter 5: Assessing lighting savings". Working Energy Resource and Training Kit: Lighting. Archived from the original on 2007-04-15. Retrieved 2007-03-17.
  40. ↑ "Low-Light Performance Calculator". Archived from the original on 2013-06-15. Retrieved 2015-05-19.
  41. ↑ "Lux Meter" (PDF). ResourceSmart.Vic.gov.au. Sustainability Victoria. April 2010. Archived from the original (PDF) on 7 July 2011. Retrieved 2021-02-08.
  42. ↑ "Illumination. - 1926.56". Regulations (Standards - 29 CFR). Occupational Safety and Health Administration, US Dept. of Labor. Archived from the original on 8 May 2009.
  43. ↑ European law UNI EN 12464
  44. ↑ Bellido-Outeirino, Francisco J. (February 2012). "Building lighting automation through the integration of DALI with wireless sensor networks". IEEE Transactions on Consumer Electronics. 58 (1): 47–52. doi:10.1109/TCE.2012.6170054. S2CID   695261.
  45. ↑ "Lighting control saves money and makes sense" (PDF). Daintree Networks.
  46. ↑ Hung-Liang, C; Yung-Hsin, H (2010). "Design and Implementation of Dimmable Electronic Ballast for Fluorescent Lamps Based on Power-Dependent Lamp Model". IEEE Transactions on Plasma Science. 38 (7): 1644–1650. Bibcode:2010ITPS...38.1644C. doi:10.1109/tps.2010.2048928. S2CID   6094389.
  47. ↑ Hanselaer P, Lootens C, Ryckaert W, Deconinck G, Rombauts P. Power density targets for efficient lighting of interior task areas. Lighting Research & Technology [serial online]. June 2007;39(2):171-182. Available from: Academic Search Premier, Ipswich, MA.
  48. ↑ Ryckaert W, Lootens C, Geldof J, Hanselaer P. Criteria for energy efficient lighting in buildings. Energy & Buildings [serial online]. March 2010;42(3):341-347. Available from: Academic Search Premier, Ipswich, MA.
  49. 1 2 Ulrich R S. View through a Windows May Influence Recovery from Surgery. Science (Washington D C) [serial online]. 1984;224(4647):420-421.
  50. ↑ Kent, Michael; Schiavon, Stefano; Jakubiec, Alstan (2020). "A dimensionality reduction method to select the most representative daylight illuminance distributions". Journal of Building Performance Simulation. 13 (1): 122–135. doi:10.1080/19401493.2019.1711456. S2CID   211093664.
  51. ↑ Chaves, Julio (2015). Introduction to Nonimaging Optics, Second Edition. CRC Press. ISBN   978-1482206739.
  52. ↑ DiLouie, Craig (2006). Advanced Lighting Controls: Energy Savings, Productivity, Technology and Applications. The Fairmont Press, Inc. ISBN   978-0-88173-510-9.
  53. ↑ Figueiro, MG; Rea, MS (2010). "Lack of short-wavelength light during the school day delays dim light melatonin onset (DLMO) in middle school students". Neuro Endocrinology Letters. 31 (1): 92–6. PMC   3349218 . PMID   20150866.
  54. ↑ Figueiro, MG; Rea, MS; Bullough, JD (2006). "Does architectural lighting contribute to breast cancer?"". Journal of Carcinogenesis. 5 (1): 20. doi: 10.1186/1477-3163-5-20 . PMC   1557490 . PMID   16901343.
  55. ↑ Newsham G, Brand J, Donnelly C, Veitch J, Aries M, Charles K. Linking indoor environment conditions to job satisfaction: a field study. Building Research & Information [serial online]. March 2009;37(2):129-147.
  56. ↑ Mientka, Matthew (25 February 2014). "Ambient Lighting Affects Decision Making, Emotional Intensity". Medical Daily. Retrieved 25 February 2014.
  57. ↑ Ellis, Marie (25 February 2014). "Room lighting affects decision making, study suggests". Medical News Today. Retrieved 25 February 2014.
  58. ↑ Wood, Janice (25 February 2014). "Got an Important Decision to Make? Dim the Lights". Psych Central News. Retrieved 25 February 2014.
  59. ↑ Gumbel, Peter (December 4, 2008). "Lighting: Bright Idea". Time. Archived from the original on 14 December 2008.
  60. 1 2 Billings, Lee (June 10, 2016). "New Map Shows the Dark Side of Artificial Light at Night". Scientific American. Retrieved June 20, 2016.
  61. ↑ "AMA Adopts Community Guidance to Reduce the Harmful Human and Environmental Effects of High Intensity Street Lighting". ama-assn.org. Retrieved 2016-06-20.
  62. ↑ Claudio L. Switch On the Night. Environmental Health Perspectives [serial online]. January 2009;117(1):A28-A31. Available from: Academic Search Premier, Ipswich, MA.
  63. ↑ Lynn A. See the Light. Parks & Recreation [serial online]. October 2010;45(10):81-82. Available from: Academic Search Premier, Ipswich, MA.
  64. ↑ Longcore, Travis; Rich, Catherine (2004). "Ecological light pollution". Frontiers in Ecology and the Environment. 2 (4): 191–198. doi:10.1890/1540-9295(2004)002[0191:ELP]2.0.CO;2. ISSN   1540-9309.
  65. ↑ Sanders, Dirk; Frago, Enric; Kehoe, Rachel; Patterson, Christophe; Gaston, Kevin J. (January 2021). "A meta-analysis of biological impacts of artificial light at night". Nature Ecology & Evolution. 5 (1): 74–81. doi:10.1038/s41559-020-01322-x. hdl: 10871/123068 . ISSN   2397-334X. PMID   33139919. S2CID   226243935.
  66. ↑ Chepesiuk, Ron (2009). "Missing the Dark: Health Effects of Light Pollution". Environ. Health Perspect. 117 (1): A20–A27. doi:10.1289/ehp.117-a20. PMC   2627884 . PMID   19165374.
  67. ↑ Carlisle, Camille M. (July 16, 2012). "AMA Addresses Light Pollution". Sky & Telescope. Retrieved June 20, 2016.
  68. ↑ Kloog, Itai; Haim, Abraham; Stevens, Richard G.; Barchana, Micha; Portnov, Boris A. (2008). "Light at night co-distributes with incident breast but not lung cancer in the female population of Israel". Chronobiology International: The Journal of Biological and Medical Rhythm Research. 25 (1): 65–81. doi:10.1080/07420520801921572. PMID   18293150. S2CID   17334188.
  69. ↑ "Society of Light and Lighting". cibse.org. Chartered Institution of Building Services Engineers.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.