Ultraviolet

Portable ultraviolet lamp

UV radiation is also produced byelectric arcs.Arc weldersmust weareye protectionand cover their skin to preventphotokeratitisand serioussunburn.

Ultraviolet(UV) light iselectromagnetic radiationofwavelengthsof 10–400 nanometers, shorter than that ofvisible light,but longer thanX-rays.UV radiation is present insunlight,and constitutes about 10% of the total electromagnetic radiation output from the Sun. It is also produced byelectric arcs,Cherenkov radiation,and specialized lights, such asmercury-vapor lamps,tanning lamps,andblack lights.

Thephotonsof ultraviolet have greater energy than those of visible light, from about 3.1 to 12electron volts,around the minimum energy required toionize atoms.Although long-wavelength ultraviolet is not considered anionizing radiationbecause itsphotonslack sufficient energy, it can inducechemical reactionsand cause many substances to glow orfluoresce.Many practical applications, including chemical and biological effects, are derived from the way that UV radiation can interact with organic molecules. These interactions can involveabsorptionor adjusting energy states in molecules, but do not necessarily involve heating.^{[citation needed]}Short-wave ultraviolet light isionizing radiation.Consequently, short-wave UV damagesDNAand sterilizes surfaces with which it comes into contact.

For humans,suntanandsunburnare familiar effects of exposure of the skin to UV light, along with an increased risk ofskin cancer.The amount of UV light produced by the Sun means that the Earth would not be able to sustain life on dry land if most of that light were not filtered out by theatmosphere.^[1]More energetic, shorter-wavelength "extreme" UV below 121 nm ionizes air so strongly that it is absorbed before it reaches the ground.^[2]However, ultraviolet light (specifically, UVB) is also responsible for the formation ofvitamin Din most landvertebrates,including humans.^[3]The UV spectrum, thus, has effects both beneficial and detrimental to life.

The lower wavelength limit of thevisible spectrumis conventionally taken as 400 nm, so ultraviolet rays are notvisible to humans,although people can sometimes perceive light at shorter wavelengths than this.^[4]Insects, birds, and some mammals can see near-UV (NUV), i.e., slightly shorter wavelengths than what humans can see.^[5]

Visibility

Ultraviolet rays are usually invisible to most humans. Thelens of the human eyeblocks most radiation in the wavelength range of 300–400 nm; shorter wavelengths are blocked by thecornea.^[6]Humans also lackcolor receptoradaptations for ultraviolet rays. Nevertheless, thephotoreceptorsof theretinaare sensitive to near-UV, and people lacking a lens (a condition known asaphakia) perceive near-UV as whitish-blue or whitish-violet.^[4]Under some conditions, children and young adults can see ultraviolet down to wavelengths around 310 nm.^[7]^[8]Near-UV radiation is visible to insects, some mammals, and somebirds.Birds have a fourth color receptor for ultraviolet rays; this, coupled with eye structures that transmit more UV gives smaller birds "true" UV vision.^[9]^[10]

History and discovery

"Ultraviolet" means "beyond violet" (fromLatinultra,"beyond" ), violet being the color of the highest frequencies ofvisible light.Ultraviolet has a higher frequency (thus a shorter wavelength) than violet light.^{[citation needed]}

UV radiation was discovered in 1801 when the German physicistJohann Wilhelm Ritterobserved that invisible rays just beyond the violet end of the visible spectrum darkenedsilver chloride-soaked paper more quickly than violet light itself. He called them "(de-)oxidizing rays" (German:de-oxidierende Strahlen) to emphasizechemical reactivityand to distinguish them from "heat rays",discovered the previous year at the other end of the visible spectrum. The simpler term" chemical rays "was adopted soon afterwards, and remained popular throughout the 19th century, although some said that this radiation was entirely different from light (notablyJohn William Draper,who named them "tithonic rays"^[11]^[12]). The terms "chemical rays" and "heat rays" were eventually dropped in favor of ultraviolet andinfrared radiation,respectively.^[13]^[14]In 1878, the sterilizing effect of short-wavelength light by killing bacteria was discovered. By 1903, the most effective wavelengths were known to be around 250 nm. In 1960, the effect of ultraviolet radiation on DNA was established.^[15]

The discovery of the ultraviolet radiation with wavelengths below 200 nm, named "vacuum ultraviolet" because it is strongly absorbed by the oxygen in air, was made in 1893 by German physicistVictor Schumann.^[16]

Subtypes

Theelectromagnetic spectrumof ultraviolet radiation (UVR), defined most broadly as 10–400 nanometers, can be subdivided into a number of ranges recommended by theISO standardISO 21348:^[17]

Name	Abbreviation	Wavelength (nm)	Photon energy (eV, aJ)	Notes/alternative names

Ultraviolet A	UV‑A	315–400	3.10–3.94, 0.497–0.631	Long-wave UV,blacklight,not absorbed by theozone layer:soft UV.
Ultraviolet B	UV‑B	280–315	3.94–4.43, 0.631–0.710	Medium-wave UV, mostly absorbed by the ozone layer: intermediate UV;Dornoradiation.
Ultraviolet C	UV‑C	100–280	4.43–12.4, 0.710–1.987	Short-wave UV,germicidalUV,ionizing radiationat shorter wavelengths, completely absorbed by the ozone layer and atmosphere: hard UV.

Near ultraviolet	N‑UV	300–400	3.10–4.13, 0.497–0.662	Visible to birds, insects, and fish.
Middle ultraviolet	M‑UV	200–300	4.13–6.20, 0.662–0.993
Far ultraviolet	F‑UV	122–200	6.20–10.16, 0.993–1.628	Ionizing radiationat shorter wavelengths.
Hydrogen Lyman-alpha	H Lyman‑α	121–122	10.16–10.25, 1.628–1.642	Spectral line at 121.6 nm, 10.20 eV.
Extreme ultraviolet	E‑UV	10–121	10.25–124, 1.642–19.867	Entirelyionizing radiationby some definitions; completely absorbed by the atmosphere.

Vacuum ultraviolet	V-UV	10–200	6.20–124, 0.993–19.867	Strongly absorbed by atmospheric oxygen, though 150–200 nm wavelengths can propagate through nitrogen.

Several solid-state and vacuum devices have been explored for use in different parts of the UV spectrum. Many approaches seek to adapt visible light-sensing devices, but these can suffer from unwanted response to visible light and various instabilities. Ultraviolet can be detected by suitablephotodiodesandphotocathodes,which can be tailored to be sensitive to different parts of the UV spectrum. Sensitive UVphotomultipliersare available.Spectrometersandradiometersare made for measurement of UV radiation. Silicon detectors are used across the spectrum.^[18]

Vacuum UV, or VUV, wavelengths (shorter than 200 nm) are strongly absorbed by molecularoxygenin the air, though the longer wavelengths around 150–200 nm can propagate throughnitrogen.Scientific instruments can, therefore, use this spectral range by operating in an oxygen-free atmosphere (commonly pure nitrogen), without the need for costly vacuum chambers. Significant examples include 193-nmphotolithographyequipment (forsemiconductor manufacturing) andcircular dichroismspectrometers.^{[citation needed]}

Technology for VUV instrumentation was largely driven by solar astronomy for many decades. While optics can be used to remove unwanted visible light that contaminates the VUV, in general; detectors can be limited by their response to non-VUV radiation, and the development ofsolar-blind deviceshas been an important area of research. Wide-gap solid-state devices or vacuum devices with high-cutoff photocathodes can be attractive compared to silicon diodes.^{[citation needed]}

Extreme UV (EUV or sometimes XUV) is characterized by a transition in the physics of interaction with matter. Wavelengths longer than about 30 nm interact mainly with the outervalence electronsof atoms, while wavelengths shorter than that interact mainly with inner-shell electrons and nuclei. The long end of the EUV spectrum is set by a prominent He⁺spectral line at 30.4 nm. EUV is strongly absorbed by most known materials, but synthesizingmultilayer opticsthat reflect up to about 50% of EUV radiation atnormal incidenceis possible. This technology was pioneered by theNIXTandMSSTAsounding rockets in the 1990s, and it has been used to make telescopes for solar imaging. See also theExtreme Ultraviolet Explorer satellite.^{[citation needed]}

Some sources use the distinction of "hard UV" and "soft UV". For instance, in the case ofastrophysics,the boundary may be at theLyman limit(wavelength 91.2 nm), with "hard UV" being more energetic;^[19]the same terms may also be used in other fields, such ascosmetology,optoelectronic,etc. The numerical values of the boundary between hard/soft, even within similar scientific fields, do not necessarily coincide; for example, one applied-physics publication used a boundary of 190 nm between hard and soft UV regions.^[20]

Solar ultraviolet

Very hot objects emit UV radiation (seeblack-body radiation). TheSunemits ultraviolet radiation at all wavelengths, including the extreme ultraviolet where it crosses into X-rays at 10 nm. Extremely hotstars(such as O- and B-type) emit proportionally more UV radiation than the Sun.Sunlightin space at the top of Earth's atmosphere (seesolar constant) is composed of about 50% infrared light, 40% visible light, and 10% ultraviolet light, for a total intensity of about 1400 W/m²in vacuum.^[21]

The atmosphere blocks about 77% of the Sun's UV, when the Sun is highest in the sky (at zenith), with absorption increasing at shorter UV wavelengths. At ground level with the sun at zenith, sunlight is 44% visible light, 3% ultraviolet, and the remainder infrared.^[22]^[23]Of the ultraviolet radiation that reaches the Earth's surface, more than 95% is the longer wavelengths of UVA, with the small remainder UVB. Almost no UVC reaches the Earth's surface.^[24]The fraction of UVA and UVB which remains in UV radiation after passing through the atmosphere is heavily dependent on cloud cover and atmospheric conditions. On "partly cloudy" days, patches of blue sky showing between clouds are also sources of (scattered) UVA and UVB, which are produced byRayleigh scatteringin the same way as the visible blue light from those parts of the sky. UVB also plays a major role in plant development, as it affects most of the plant hormones.^[25]During total overcast, the amount of absorption due to clouds is heavily dependent on the thickness of the clouds and latitude, with no clear measurements correlating specific thickness and absorption of UVA and UVB.^[26]

The shorter bands of UVC, as well as even more-energetic UV radiation produced by the Sun, are absorbed by oxygen and generate the ozone in theozone layerwhen single oxygen atoms produced by UVphotolysisof dioxygen react with more dioxygen. The ozone layer is especially important in blocking most UVB and the remaining part of UVC not already blocked by ordinary oxygen in air.

Blockers, absorbers, and windows

Ultraviolet absorbers are molecules used in organic materials (polymers,paints,etc.) to absorb UV radiation to reduce theUV degradation(photo-oxidation) of a material. The absorbers can themselves degrade over time, so monitoring of absorber levels in weathered materials is necessary.^{[citation needed]}

Insunscreen,ingredients that absorb UVA/UVB rays, such asavobenzone,oxybenzone^[27]andoctyl methoxycinnamate,areorganic chemical absorbersor "blockers". They are contrasted with inorganic absorbers/ "blockers" of UV radiation such ascarbon black,titanium dioxide,andzinc oxide.^{[citation needed]}

For clothing, theultraviolet protection factor(UPF) represents the ratio ofsunburn-causing UV without and with the protection of the fabric, similar tosun protection factor(SPF) ratings forsunscreen.^{[citation needed]}Standard summer fabrics have UPFs around 6, which means that about 20% of UV will pass through.^{[citation needed]}

Suspendednanoparticlesin stained-glass prevent UV rays from causing chemical reactions that change image colors.^{[citation needed]}A set of stained-glass color-reference chips is planned to be used to calibrate the color cameras for the 2019ESAMars rover mission, since they will remain unfaded by the high level of UV present at the surface of Mars.^{[citation needed]}

Commonsoda–lime glass,such as window glass, is partiallytransparentto UVA, but isopaqueto shorter wavelengths, passing about 90% of the light above 350 nm, but blocking over 90% of the light below 300 nm.^[28]^[29]^[30]A study found that car windows allow 3–4% of ambient UV to pass through, especially if the UV was greater than 380 nm.^[31]Other types of car windows can reduce transmission of UV that is greater than 335 nm.^[31]Fused quartz,depending on quality, can be transparent even tovacuum UVwavelengths. Crystallinequartzand some crystals such as CaF₂and MgF₂transmit well down to 150 nm or 160 nm wavelengths.^[32]

Wood's glassis a deep violet-blue barium-sodium silicate glass with about 9%nickel oxidedeveloped duringWorld War Ito block visible light for covert communications. It allows both infrared daylight and ultraviolet night-time communications by being transparent between 320 nm and 400 nm and also the longer infrared and just-barely-visible red wavelengths. Its maximum UV transmission is at 365 nm, one of the wavelengths ofmercury lamps.^{[citation needed]}

Artificial sources

"Black lights"

Two black light fluorescent tubes, showing use. The longer tube is a F15T8/BLB 18 inch, 15 watt tube, shown in the bottom image in a standard plug-in fluorescent fixture. The shorter is an F8T5/BLB 12 inch, 8 watt tube, used in a portable battery-powered black light sold as a pet urine detector.

Ablack lightlamp emits long-wave UV‑A radiation and little visible light. Fluorescent black light lamps work similarly to otherfluorescent lamps,but use aphosphoron the inner tube surface which emits UV‑A radiation instead of visible light. Some lamps use a deep-bluish-purpleWood's glassoptical filter that blocks almost all visible light with wavelengths longer than 400 nanometers.^[33]The purple glow given off by these tubes is not the ultraviolet itself, but visible purple light from mercury's 404 nm spectral line which escapes being filtered out by the coating. Other black lights use plain glass instead of the more expensive Wood's glass, so they appear light-blue to the eye when operating.^{[citation needed]}

Incandescent black lights are also produced, using a filter coating on the envelope of an incandescent bulb that absorbs visible light (see section below). These are cheaper but very inefficient, emitting only a small fraction of a percent of their power as UV.Mercury-vaporblack lights in ratings up to 1 kW with UV-emitting phosphor and an envelope ofWood's glassare used for theatrical and concert displays.^{[citation needed]}

Black lights are used in applications in which extraneous visible light must be minimized; mainly to observefluorescence,the colored glow that many substances give off when exposed to UV light. UV‑A /UV‑B emitting bulbsare also sold for other special purposes, such astanning lampsand reptile-husbandry.^{[citation needed]}

Short-wave ultraviolet lamps

9 watt germicidal UV bulb, in compact fluorescent (CF) form factor

Commercial germicidal lamp in butcher shop

Shortwave UV lamps are made using afluorescent lamptube with no phosphor coating, composed offused quartzorvycor,since ordinary glass absorbs UV‑C. These lamps emit ultraviolet light with two peaks in the UV‑C band at 253.7 nm and 185 nm due to themercurywithin the lamp, as well as some visible light. From 85% to 90% of the UV produced by these lamps is at 253.7 nm, whereas only 5–10% is at 185 nm.^[34]The fused quartz tube passes the 253.7 nm radiation but blocks the 185 nm wavelength. Such tubes have two or three times the UV‑C power of a regular fluorescent lamp tube. These low-pressure lamps have a typical efficiency of approximately 30–40%, meaning that for every 100 watts of electricity consumed by the lamp, they will produce approximately 30–40 watts of total UV output. They also emit bluish-white visible light, due to mercury's other spectral lines. These "germicidal" lamps are used extensively for disinfection of surfaces in laboratories and food-processing industries, and for disinfecting water supplies.^{[citation needed]}

Incandescent lamps

'Black light'incandescent lampsare also made from an incandescent light bulb with a filter coating which absorbs most visible light.Halogen lampswithfused quartzenvelopes are used as inexpensive UV light sources in the near UV range, from 400 to 300 nm, in some scientific instruments. Due to itsblack-body spectruma filament light bulb is a very inefficient ultraviolet source, emitting only a fraction of a percent of its energy as UV.^{[citation needed]}

Gas-discharge lamps

Specialized UVgas-discharge lampscontaining different gases produce UV radiation at particular spectral lines for scientific purposes.Argonanddeuterium arc lampsare often used as stable sources, either windowless or with various windows such asmagnesium fluoride.^[35]These are often the emitting sources in UV spectroscopy equipment for chemical analysis.^{[citation needed]}

Other UV sources with more continuous emission spectra includexenon arc lamps(commonly used as sunlight simulators),deuterium arc lamps,mercury-xenon arc lamps,andmetal-halide arc lamps.^{[citation needed]}

Theexcimer lamp,a UV source developed in the early 2000s, is seeing increasing use in scientific fields. It has the advantages of high-intensity, high efficiency, and operation at a variety of wavelength bands into the vacuum ultraviolet.^{[citation needed]}

Ultraviolet LEDs

Light-emitting diodes(LEDs) can be manufactured to emit radiation in the ultraviolet range. In 2019, following significant advances over the preceding five years, UV‑A LEDs of 365 nm and longer wavelength were available, with efficiencies of 50% at 1.0 W output. Currently, the most common types of UV LEDs are in 395 nm and 365 nm wavelengths, both of which are in the UV‑A spectrum. The rated wavelength is the peak wavelength that the LEDs put out, but light at both higher and lower wavelengths are present.^{[citation needed]}

The cheaper and more common 395 nm UV LEDs are much closer to the visible spectrum, and give off a purple color. Other UV LEDs deeper into the spectrum do not emit as much visible light^[36]LEDs are used for applications such asUV curingapplications, charging glow-in-the-dark objects such as paintings or toys, and lights for detecting counterfeit money and bodily fluids. UV LEDs are also used in digital print applications and inert UV curing environments. Power densities approaching 3 W/cm²(30 kW/m²) are now possible, and this, coupled with recent developments by photo-initiator and resin formulators, makes the expansion of LED cured UV materials likely.^{[citation needed]}

UV‑C LEDs are developing rapidly, but may require testing to verify effective disinfection. Citations for large-area disinfection are for non-LED UV sources^[37]known asgermicidal lamps.^[38]Also, they are used as line sources to replacedeuterium lampsinliquid chromatographyinstruments.^[39]

Ultraviolet lasers

Gas lasers,laser diodes,andsolid-state laserscan be manufactured to emit ultraviolet rays, and lasers are available that cover the entire UV range. Thenitrogen gas laseruses electronic excitation of nitrogen molecules to emit a beam that is mostly UV. The strongest ultraviolet lines are at 337.1 nm and 357.6 nm in wavelength. Another type of high-power gas lasers areexcimer lasers.They are widely used lasers emitting in ultraviolet and vacuum ultraviolet wavelength ranges. Presently, UVargon-fluorideexcimer lasers operating at 193 nm are routinely used inintegrated circuitproduction byphotolithography.The current^[timeframe?]wavelength limit of production of coherent UV is about 126 nm, characteristic of the Ar₂* excimer laser.^{[citation needed]}

Direct UV-emitting laser diodes are available at 375 nm.^[40]UV diode-pumped solid state lasers have been demonstrated usingcerium-dopedlithium strontium aluminum fluoride crystals (Ce:LiSAF), a process developed in the 1990s atLawrence Livermore National Laboratory.^[41]Wavelengths shorter than 325 nm are commercially generated indiode-pumped solid-state lasers.Ultraviolet lasers can also be made by applyingfrequency conversionto lower-frequency lasers.^{[citation needed]}

Ultraviolet lasers have applications in industry (laser engraving), medicine (dermatology,andkeratectomy), chemistry (MALDI),free-air secure communications,computing (optical storage), and manufacture of integrated circuits.^{[citation needed]}

Tunable vacuum ultraviolet (VUV)

The vacuum ultraviolet (V‑UV) band (100–200 nm) can be generated bynon-linear 4 wave mixingin gases by sum or difference frequency mixing of 2 or more longer wavelength lasers. The generation is generally done in gasses (e.g. krypton, hydrogen which are two-photon resonant near 193 nm)^[42]or metal vapors (e.g. magnesium). By making one of the lasers tunable, the V‑UV can be tuned. If one of the lasers is resonant with a transition in the gas or vapor then the V‑UV production is intensified. However, resonances also generate wavelength dispersion, and thus the phase matching can limit the tunable range of the 4 wave mixing. Difference frequency mixing (i.e., $f$ ₁+ $f$ ₂− $f$ ₃) has an advantage over sum frequency mixing because the phase matching can provide greater tuning.^[42]

In particular, difference frequency mixing two photons of anAr F(193 nm) excimer laser with a tunable visible or near IR laser in hydrogen or krypton provides resonantly enhanced tunable V‑UV covering from 100 nm to 200 nm.^[42]Practically, the lack of suitable gas / vapor cell window materials above thelithium fluoridecut-off wavelength limit the tuning range to longer than about 110 nm. Tunable V‑UV wavelengths down to 75 nm was achieved using window-free configurations.^[43]

Plasma and synchrotron sources of extreme UV

Lasers have been used to indirectly generate non-coherent extreme UV (E‑UV) radiation at 13.5 nm forextreme ultraviolet lithography.The E‑UV is not emitted by the laser, but rather by electron transitions in an extremely hot tin or xenon plasma, which is excited by an excimer laser.^[44]This technique does not require a synchrotron, yet can produce UV at the edge of the X‑ray spectrum.Synchrotron light sourcescan also produce all wavelengths of UV, including those at the boundary of the UV and X‑ray spectra at 10 nm.^{[citation needed]}

Human health-related effects

The impact of ultraviolet radiation onhuman healthhas implications for the risks and benefits of sun exposure and is also implicated in issues such asfluorescent lamps and health.Getting too much sun exposure can be harmful, but in moderation, sun exposure is beneficial.^[45]

Beneficial effects

UV light (specifically, UV‑B) causes the body to producevitamin D,^[46]which is essential for life. Humans need some UV radiation to maintain adequate vitamin D levels. According to the World Health Organization:^[47]

There is no doubt that a little sunlight is good for you! But 5–15 minutes of casual sun exposure of hands, face and arms two to three times a week during the summer months is sufficient to keep your vitamin D levels high.

Vitamin D can also be obtained from food and supplementation.^[48]Excess sun exposure produces harmful effects, however.^[47]

Vitamin D promotes the creation ofserotonin.The production of serotonin is in direct proportion to the degree of bright sunlight the body receives.^[49]Serotonin is thought to provide sensations of happiness, well-being and serenity to human beings.^[50]

Skin conditions

UV rays also treat certain skin conditions. Modern phototherapy has been used to successfully treatpsoriasis,eczema,jaundice,vitiligo,atopic dermatitis,and localizedscleroderma.^[51]^[52]In addition, UV light, in particular UV‑B radiation, has been shown to inducecell cyclearrest inkeratinocytes,the most common type of skin cell.^[53]As such, sunlight therapy can be a candidate for treatment of conditions such as psoriasis andexfoliative cheilitis,conditions in which skin cells divide more rapidly than usual or necessary.^[54]

Harmful effects

In humans, excessive exposure to UV radiation can result in acute and chronic harmful effects on the eye's dioptric system andretina.The risk is elevated at highaltitudesand people living in highlatitudeareas where snow covers the ground right into early summer and sun positions even atzenithare low, are particularly at risk.^[55]Skin, thecircadiansystem, and theimmune systemcan also be affected.^[56]

The differential effects of various wavelengths of light on the human cornea and skin are sometimes called the "erythemal action spectrum".^[57]The action spectrum shows that UVA does not cause immediate reaction, but rather UV begins to causephotokeratitisand skin redness (with lighter skinned individuals being more sensitive) at wavelengths starting near the beginning of the UVB band at 315 nm, and rapidly increasing to 300 nm. The skin and eyes are most sensitive to damage by UV at 265–275 nm, which is in the lower UV‑C band. At still shorter wavelengths of UV, damage continues to happen, but the overt effects are not as great with so little penetrating the atmosphere. TheWHO-standardultraviolet indexis a widely publicized measurement of total strength of UV wavelengths that cause sunburn on human skin, by weighting UV exposure for action spectrum effects at a given time and location. This standard shows that most sunburn happens due to UV at wavelengths near the boundary of the UV‑A and UV‑B bands.^{[citation needed]}

Skin damage

Overexposure to UV‑B radiation not only can causesunburnbut also some forms ofskin cancer.However, the degree of redness and eye irritation (which are largely not caused by UV‑A) do not predict the long-term effects of UV, although they do mirror the direct damage of DNA by ultraviolet.^[58]

All bands of UV radiation damagecollagenfibers and accelerate aging of the skin. Both UV‑A and UV‑B destroy vitamin A in skin, which may cause further damage.^[59]

UVB radiation can cause direct DNA damage.^[60]This cancer connection is one reason for concern aboutozone depletionand the ozone hole.

The most deadly form ofskin cancer,malignantmelanoma,is mostly caused by DNA damage independent from UV‑A radiation. This can be seen from the absence of a direct UV signature mutation in 92% of all melanoma.^[61]Occasional overexposure and sunburn are probably greater risk factors for melanoma than long-term moderate exposure.^[62]UV‑C is the highest-energy, most-dangerous type of ultraviolet radiation, and causes adverse effects that can variously be mutagenic or carcinogenic.^[63]

In the past, UV‑A was considered not harmful or less harmful than UV‑B, but today it is known to contribute to skin cancer viaindirect DNA damage(free radicals such as reactive oxygen species).^{[citation needed]}UV‑A can generate highly reactive chemical intermediates, such as hydroxyl and oxygen radicals, which in turn can damage DNA. The DNA damage caused indirectly to skin by UV‑A consists mostly of single-strand breaks in DNA, while the damage caused by UV‑B includes direct formation ofthymine dimersorcytosine dimersand double-strand DNA breakage.^[64]UV‑A is immunosuppressive for the entire body (accounting for a large part of the immunosuppressive effects of sunlight exposure), and is mutagenic for basal cell keratinocytes in skin.^[65]

UVB photons can cause direct DNA damage. UV‑B radiationexcitesDNA molecules in skin cells, causing aberrantcovalent bondsto form between adjacentpyrimidinebases, producing adimer.Most UV-induced pyrimidine dimers in DNA are removed by the process known asnucleotide excision repairthat employs about 30 different proteins.^[60]Those pyrimidine dimers that escape this repair process can induce a form of programmed cell death (apoptosis) or can cause DNA replication errors leading tomutation.^{[citation needed]}

As a defense against UV radiation, the amount of the brown pigmentmelaninin the skin increases when exposed to moderate (depending onskin type) levels of radiation; this is commonly known as asun tan.The purpose of melanin is to absorb UV radiation and dissipate the energy as harmless heat, protecting the skin against bothdirectandindirect DNA damagefrom the UV. UV‑A gives a quick tan that lasts for days by oxidizing melanin that was already present and triggers the release of themelaninfrommelanocytes.UV‑B yields a tan that takes roughly 2 days to develop because it stimulates the body to produce more melanin.^{[citation needed]}

Sunscreen safety debate

Medical organizations recommend that patients protect themselves from UV radiation by usingsunscreen.Five sunscreen ingredients have been shown to protect mice against skin tumors. However,some sunscreen chemicalsproduce potentially harmful substances if they are illuminated while in contact with living cells.^[66]^[67]The amount of sunscreen that penetrates into the lower layers of the skin may be large enough to cause damage.^[68]

Sunscreen reduces the direct DNA damage that causes sunburn, by blocking UV‑B, and the usualSPF ratingindicates how effectively this radiation is blocked. SPF is, therefore, also called UVB-PF, for "UV‑B protection factor".^[69]This rating, however, offers no data about important protection against UVA,^[70]which does not primarily cause sunburn but is still harmful, since it causes indirect DNA damage and is also considered carcinogenic. Several studies suggest that the absence of UV‑A filters may be the cause of the higher incidence of melanoma found in sunscreen users compared to non-users.^[71]^[72]^[73]^[74]^[75]Some sunscreen lotions containtitanium dioxide,zinc oxide,andavobenzone,which help protect against UV‑A rays.

The photochemical properties of melanin make it an excellentphotoprotectant.However, sunscreen chemicals cannot dissipate the energy of the excited state as efficiently as melanin and therefore, if sunscreen ingredients penetrate into the lower layers of the skin, the amount ofreactive oxygen speciesmay be increased.^[76]^[66]^[67]^[77]The amount of sunscreen that penetrates through thestratum corneummay or may not be large enough to cause damage.

In an experiment by Hansonet al.that was published in 2006, the amount of harmfulreactive oxygen species(ROS) was measured in untreated and in sunscreen treated skin. In the first 20 minutes, the film of sunscreen had a protective effect and the number of ROS species was smaller. After 60 minutes, however, the amount of absorbed sunscreen was so high that the amount of ROS was higher in the sunscreen-treated skin than in the untreated skin.^[76]The study indicates that sunscreen must be reapplied within 2 hours in order to prevent UV light from penetrating to sunscreen-infused live skin cells.^[76]

Aggravation of certain skin conditions

Ultraviolet radiation can aggravate several skin conditions and diseases, including^[78]systemic lupus erythematosus,Sjögren's syndrome,Sinear Usher syndrome,rosacea,dermatomyositis,Darier's disease,Kindler–Weary syndromeandPorokeratosis.^[79]

Eye damage

The eye is most sensitive to damage by UV in the lower UV‑C band at 265–275 nm. Radiation of this wavelength is almost absent from sunlight at the surface of the Earth but is emitted by artificial sources such as theelectrical arcsemployed inarc welding.Unprotected exposure to these sources can cause "welder's flash" or "arc eye" (photokeratitis) and can lead tocataracts,pterygiumandpingueculaformation. To a lesser extent, UV‑B in sunlight from 310 to 280 nm also causes photokeratitis ( "snow blindness" ), and thecornea,thelens,and theretinacan be damaged.^[80]

Protective eyewearis beneficial to those exposed to ultraviolet radiation. Since light can reach the eyes from the sides, full-coverage eye protection is usually warranted if there is an increased risk of exposure, as in high-altitude mountaineering. Mountaineers are exposed to higher-than-ordinary levels of UV radiation, both because there is less atmospheric filtering and because of reflection from snow and ice.^[81]^[82] Ordinary, untreatedeyeglassesgive some protection. Most plastic lenses give more protection than glass lenses, because, as noted above, glass is transparent to UV‑A and the common acrylic plastic used for lenses is less so. Some plastic lens materials, such aspolycarbonate,inherently block most UV.^[83]

Degradation of polymers, pigments and dyes

UV damagedpolypropylenerope (left) and new rope (right)

UV degradationis one form ofpolymer degradationthat affects plastics exposed tosunlight.The problem appears as discoloration or fading, cracking, loss of strength or disintegration. The effects of attack increase with exposure time and sunlight intensity. The addition of UV absorbers inhibits the effect.

IR spectrum showingcarbonylabsorption due to UV degradation ofpolyethylene

Sensitive polymers includethermoplasticsand speciality fibers likearamids.UV absorption leads to chain degradation and loss of strength at sensitive points in the chain structure. Aramid rope must be shielded with a sheath of thermoplastic if it is to retain its strength.^{[citation needed]}

Manypigmentsanddyesabsorb UV and change colour, sopaintingsand textiles may need extra protection both from sunlight and fluorescent lamps, two common sources of UV radiation. Window glass absorbs some harmful UV, but valuable artifacts need extra shielding. Many museums place black curtains overwatercolour paintingsand ancient textiles, for example. Since watercolours can have very low pigment levels, they need extra protection from UV. Various forms ofpicture framing glass,including acrylics (plexiglass), laminates, and coatings, offer different degrees of UV (and visible light) protection.^{[citation needed]}

Applications

Because of its ability to cause chemical reactions and excitefluorescencein materials, ultraviolet radiation has a number of applications. The following table^[84]gives some uses of specific wavelength bands in the UV spectrum.

13.5 nm:Extreme ultraviolet lithography
30–200 nm:Photoionization,ultraviolet photoelectron spectroscopy,standardintegrated circuitmanufacture byphotolithography
230–365 nm:UV-ID, label tracking,barcodes
230–400 nm:Opticalsensors,various instrumentation
240–280 nm:Disinfection,decontamination of surfaces and water (DNAabsorption has a peak at 260 nm),germicidal lamps^[38]
200–400 nm:Forensic analysis,drug detection
270–360 nm:Proteinanalysis,DNA sequencing,drug discovery
280–400 nm:Medical imagingofcells
300–320 nm:Light therapyin medicine
300–365 nm:Curingofpolymersandprinter inks
350–370 nm:Bug zappers(flies are most attracted to light at 365 nm)^[85]

Photography

Photographic film responds to ultraviolet radiation but the glass lenses of cameras usually block radiation shorter than 350 nm. Slightly yellow UV-blocking filters are often used for outdoor photography to prevent unwanted bluing and overexposure by UV rays. For photography in the near UV, special filters may be used. Photography with wavelengths shorter than 350 nm requires special quartz lenses which do not absorb the radiation. Digital cameras sensorsmay have internal filters that block UV to improve color rendition accuracy. Sometimes these internal filters can be removed, or they may be absent, and an external visible-light filter prepares the camera for near-UV photography. A few cameras are designed for use in the UV.^{[citation needed]}

Photography by reflected ultraviolet radiation is useful for medical, scientific, and forensic investigations, in applications as widespread as detecting bruising of skin, alterations of documents, or restoration work on paintings. Photography of the fluorescence produced by ultraviolet illumination uses visible wavelengths of light.^{[citation needed]}

Aurora atJupiter's north pole as seen in ultraviolet light by theHubble Space Telescope

Inultraviolet astronomy,measurements are used to discern the chemical composition of the interstellar medium, and the temperature and composition of stars. Because the ozone layer blocks many UV frequencies from reaching telescopes on the surface of the Earth, most UV observations are made from space.^{[citation needed]}

Electrical and electronics industry

Corona dischargeon electrical apparatus can be detected by its ultraviolet emissions. Corona causes degradation of electrical insulation and emission ofozoneandnitrogen oxide.^[86]

EPROMs(Erasable Programmable Read-Only Memory) are erased by exposure to UV radiation. These modules have a transparent (quartz) window on the top of the chip that allows the UV radiation in.

Fluorescent dye uses

Colorlessfluorescent dyesthat emit blue light under UV are added asoptical brightenersto paper and fabrics. The blue light emitted by these agents counteracts yellow tints that may be present and causes the colors and whites to appear whiter or more brightly colored.

UV fluorescent dyes that glow in the primary colors are used in paints, papers, and textiles either to enhance color under daylight illumination or to provide special effects when lit with UV lamps.Blacklight paintsthat contain dyes that glow under UV are used in a number of art and aesthetic applications.^{[citation needed]}

Amusement parks often use UV lighting to fluoresce ride artwork and backdrops. This often has the side effect of causing rider's white clothing to glow light-purple.^{[citation needed]}

To help preventcounterfeitingof currency, or forgery of important documents such as driver's licenses andpassports,the paper may include a UVwatermarkor fluorescent multicolor fibers that are visible under ultraviolet light. Postage stamps aretaggedwith a phosphor that glows under UV rays to permit automatic detection of the stamp and facing of the letter.

UV fluorescentdyesare used in many applications (for example,biochemistryandforensics). Some brands ofpepper spraywill leave an invisible chemical (UV dye) that is not easily washed off on a pepper-sprayed attacker, which would help police identify the attacker later.

In some types ofnondestructive testingUV stimulates fluorescent dyes to highlight defects in a broad range of materials. These dyes may be carried into surface-breaking defects by capillary action (liquid penetrant inspection) or they may be bound to ferrite particles caught in magnetic leakage fields in ferrous materials (magnetic particle inspection).

Analytic uses

Forensics

UV is an investigative tool at the crime scene helpful in locating and identifying bodily fluids such as semen, blood, and saliva.^[87]For example, ejaculated fluids or saliva can be detected by high-power UV sources, irrespective of the structure or colour of the surface the fluid is deposited upon.^[88]UV–vis microspectroscopyis also used to analyze trace evidence, such as textile fibers and paint chips, as well as questioned documents.

Other applications include the authentication of various collectibles and art, and detecting counterfeit currency. Even materials not specially marked with UV sensitive dyes may have distinctive fluorescence under UV exposure or may fluoresce differently under short-wave versus long-wave ultraviolet.

Enhancing contrast of ink

Using multi-spectral imaging it is possible to read illegiblepapyrus,such as the burned papyri of theVilla of the Papyrior ofOxyrhynchus,or theArchimedes palimpsest.The technique involves taking pictures of the illegible document using different filters in the infrared or ultraviolet range, finely tuned to capture certain wavelengths of light. Thus, the optimum spectral portion can be found for distinguishing ink from paper on the papyrus surface.

Simple NUV sources can be used to highlight faded iron-basedinkonvellum.^[89]

Sanitary compliance

Ultraviolet helps detect organic material deposits that remain on surfaces where periodic cleaning and sanitizing may have failed. It is used in the hotel industry, manufacturing, and other industries where levels of cleanliness or contamination areinspected.^[90]^[91]^[92]^[93]

Perennial news features for many television news organizations involve an investigative reporter using a similar device to reveal unsanitary conditions in hotels, public toilets, hand rails, and such.^[94]^[95]

Chemistry

UV/Vis spectroscopyis widely used as a technique inchemistryto analyzechemical structure,the most notable one beingconjugated systems.UV radiation is often used to excite a given sample where the fluorescent emission is measured with aspectrofluorometer.In biological research, UV radiation is used forquantification of nucleic acidsorproteins.In environmental chemistry, UV radiation could also be used to detectContaminants of emerging concernin water samples.^[96]

In pollution control applications, ultraviolet analyzers are used to detect emissions of nitrogen oxides, sulfur compounds, mercury, and ammonia, for example in the flue gas of fossil-fired power plants.^[97]Ultraviolet radiation can detect thin sheens ofspilled oilon water, either by the high reflectivity of oil films at UV wavelengths, fluorescence of compounds in oil, or by absorbing of UV created byRaman scatteringin water.^[98]UV absorbance can also be uesd to quantify contaminants in wastewater. Most commonly used 254 nm UV absorbance is genrally used as a surrogate parameters to quantify NOM.^[96]Another form of light-based detection method uses a wide spectrum of excitation emission matrix (EEM) to detect and identify contaminants based on their flourense properties.^[96]^[99]EEM could be used to discriminate different groups of NOM based on the difference in light emission and excitation of fluorophores. NOMs with certain molecular structures are reported to have fluorescent properties in a wide range of excitation/emission wavelengths.^[100]^[96]

Ultraviolet lamps are also used as part of the analysis of somemineralsandgems.

Material science uses

Fire detection

In general, ultraviolet detectors use either a solid-state device, such as one based onsilicon carbideoraluminium nitride,or a gas-filled tube as the sensing element. UV detectors that are sensitive to UV in any part of the spectrum respond to irradiation bysunlightandartificial light.A burning hydrogen flame, for instance, radiates strongly in the 185- to 260-nanometer range and only very weakly in theIRregion, whereas a coal fire emits very weakly in the UV band yet very strongly at IR wavelengths; thus, a fire detector that operates using both UV and IR detectors is more reliable than one with a UV detector alone. Virtually all fires emit someradiationin the UVC band, whereas theSun's radiation at this band is absorbed by theEarth's atmosphere.The result is that the UV detector is "solar blind", meaning it will not cause an alarm in response to radiation from the Sun, so it can easily be used both indoors and outdoors.

UV detectors are sensitive to most fires, includinghydrocarbons,metals,sulfur,hydrogen,hydrazine,andammonia.Arc welding,electrical arcs,lightning,X-raysused in nondestructive metal testing equipment (though this is highly unlikely), and radioactive materials can produce levels that will activate a UV detection system. The presence of UV-absorbing gases and vapors will attenuate the UV radiation from a fire, adversely affecting the ability of the detector to detect flames. Likewise, the presence of an oil mist in the air or an oil film on the detector window will have the same effect.

Photolithography

Ultraviolet radiation is used for very fine resolutionphotolithography,a procedure wherein a chemical called a photoresist is exposed to UV radiation that has passed through a mask. The exposure causes chemical reactions to occur in the photoresist. After removal of unwanted photoresist, a pattern determined by the mask remains on the sample. Steps may then be taken to "etch" away, deposit on or otherwise modify areas of the sample where no photoresist remains.

Photolithography is used in the manufacture ofsemiconductors,integrated circuitcomponents,^[101]andprinted circuit boards.Photolithography processes used to fabricate electronic integrated circuits presently use 193 nm UV and are experimentally using 13.5 nm UV forextreme ultraviolet lithography.

Polymers

Electronic components that require clear transparency for light to exit or enter (photovoltaic panels and sensors) can be potted using acrylic resins that are cured using UV energy. The advantages are low VOC emissions and rapid curing.

Certain inks, coatings, andadhesivesare formulated with photoinitiators and resins. When exposed to UV light,polymerizationoccurs, and so the adhesives harden or cure, usually within a few seconds. Applications include glass and plastic bonding,optical fibercoatings, the coating of flooring,UV coatingand paper finishes in offsetprinting,dental fillings, and decorative fingernail "gels".

UV sources for UV curing applications includeUV lamps,UVLEDs,andexcimerflash lamps. Fast processes such as flexo or offset printing require high-intensity light focused via reflectors onto a moving substrate and medium so high-pressureHg(mercury) orFe(iron, doped)-based bulbs are used, energized with electric arcs or microwaves. Lower-power fluorescent lamps and LEDs can be used for static applications. Small high-pressure lamps can have light focused and transmitted to the work area via liquid-filled or fiber-optic light guides.

The impact of UV on polymers is used for modification of the (roughnessandhydrophobicity) of polymer surfaces. For example, apoly(methyl methacrylate)surface can be smoothed by vacuum ultraviolet.^[102]

UV radiation is useful in preparing low-surface-energypolymersfor adhesives. Polymers exposed to UV will oxidize, thus raising thesurface energyof the polymer. Once the surface energy of the polymer has been raised, the bond between the adhesive and the polymer is stronger.

Biology-related uses

Air purification

Using acatalytic chemical reactionfromtitanium dioxideand UVC exposure,oxidationof organic matter convertspathogens,pollens,andmold sporesinto harmless inert byproducts. However, the reaction of titanium dioxide and UVC is not a straight path. Several hundreds of reactions occur prior to the inert byproducts stage and can hinder the resulting reaction creating formaldehyde, aldehyde, and other VOC's en route to a final stage. Thus, the use of titanium dioxide and UVC requires very specific parameters for a successful outcome. The cleansing mechanism of UV is a photochemical process. Contaminants in the indoor environment are almost entirely organic carbon-based compounds, which break down when exposed to high-intensity UV at 240 to 280 nm. Short-wave ultraviolet radiation can destroy DNA in living microorganisms.^[103]UVC's effectiveness is directly related to intensity and exposure time.

UV has also been shown to reduce gaseous contaminants such ascarbon monoxideandVOCs.^[104]^[105]^[106]UV lamps radiating at 184 and 254 nm can remove low concentrations ofhydrocarbonsandcarbon monoxideif the air is recycled between the room and the lamp chamber. This arrangement prevents the introduction of ozone into the treated air. Likewise, air may be treated by passing by a single UV source operating at 184 nm and passed over iron pentaoxide to remove the ozone produced by the UV lamp.

Sterilization and disinfection

Ultraviolet lampsare used tosterilizeworkspaces and tools used in biology laboratories and medical facilities. Commercially available low-pressuremercury-vapor lampsemit about 86% of their radiation at 254 nanometers (nm), with 265 nm being the peak germicidal effectiveness curve. UV at these germicidal wavelengths damage a microorganism's DNA/RNA so that it cannot reproduce, making it harmless, (even though the organism may not be killed).^[107]Since microorganisms can be shielded from ultraviolet rays in small cracks and other shaded areas, these lamps are used only as a supplement to other sterilization techniques.

UV-C LEDs are relatively new to the commercial market and are gaining in popularity.^{[failed verification]}^[108]Due to their monochromatic nature (±5 nm)^{[failed verification]}these LEDs can target a specific wavelength needed for disinfection. This is especially important knowing that pathogens vary in their sensitivity to specific UV wavelengths. LEDs are mercury free, instant on/off, and have unlimited cycling throughout the day.^[109]

Disinfectionusing UV radiation is commonly used inwastewatertreatment applications and is finding an increased usage in municipal drinkingwater treatment.Many bottlers of spring water use UV disinfection equipment to sterilize their water.Solar water disinfection^[110]has been researched for cheaply treating contaminated water using naturalsunlight.The UV-A irradiation and increased water temperature kill organisms in the water.

Ultraviolet radiation is used in several food processes to kill unwantedmicroorganisms.UV can be used topasteurizefruit juices by flowing the juice over a high-intensity ultraviolet source. The effectiveness of such a process depends on the UVabsorbanceof the juice.

Pulsed light(PL) is a technique of killing microorganisms on surfaces using pulses of an intense broad spectrum, rich in UV-C between 200 and 280nm.Pulsed light works withxenon flash lampsthat can produce flashes several times per second.Disinfection robotsuse pulsed UV.^[111]

The antimicrobial effectiveness of filtered far-UVC (222 nm) light on a range of pathogens, including bacteria and fungi showed inhibition of pathogen growth, and since it has lesser harmful effects, it provides essential insights for reliable disinfection in healthcare settings, such as hospitals and long-term care homes.^[112]UVC has also been shown to be effective at degrading SARS-CoV-2 virus.^[113]

Biological

Some animals, including birds, reptiles, and insects such as bees, can see near-ultraviolet wavelengths. Many fruits, flowers, and seeds stand out more strongly from the background in ultraviolet wavelengths as compared to human color vision. Scorpions glow or take on a yellow to green color under UV illumination, thus assisting in the control of these arachnids. Many birds have patterns in their plumage that are invisible at usual wavelengths but observable in ultraviolet, and the urine and other secretions of some animals, including dogs, cats, and human beings, are much easier to spot with ultraviolet. Urine trails of rodents can be detected by pest control technicians for proper treatment of infested dwellings.

Butterflies use ultraviolet as acommunication systemfor sex recognition and mating behavior. For example, in theColias eurythemebutterfly, males rely on visual cues to locate and identify females. Instead of using chemical stimuli to find mates, males are attracted to the ultraviolet-reflecting color of female hind wings.^[114]InPieris napibutterflies it was shown that females in northern Finland with less UV-radiation present in the environment possessed stronger UV signals to attract their males than those occurring further south. This suggested that it was evolutionarily more difficult to increase the UV-sensitivity of the eyes of the males than to increase the UV-signals emitted by the females.^[115]

Many insects use the ultraviolet wavelength emissions from celestial objects as references for flight navigation. A local ultraviolet emitter will normally disrupt the navigation process and will eventually attract the flying insect.

Thegreen fluorescent protein(GFP) is often used ingeneticsas a marker. Many substances, such as proteins, have significant light absorption bands in the ultraviolet that are of interest in biochemistry and related fields. UV-capable spectrophotometers are common in such laboratories.

Ultraviolet traps calledbug zappersare used to eliminate various small flying insects. They are attracted to the UV and are killed using an electric shock, or trapped once they come into contact with the device. Different designs of ultraviolet radiation traps are also used byentomologistsforcollecting nocturnalinsects duringfaunisticsurvey studies.

Therapy

Ultraviolet radiation is helpful in the treatment ofskin conditionssuch aspsoriasisandvitiligo.Exposure to UVA, while the skin is hyper-photosensitive, by takingpsoralensis an effective treatment forpsoriasis.Due to the potential ofpsoralensto cause damage to theliver,PUVA therapymay be used only a limited number of times over a patient's lifetime.

UVB phototherapy does not require additional medications or topical preparations for the therapeutic benefit; only the exposure is needed. However, phototherapy can be effective when used in conjunction with certain topical treatments such as anthralin, coal tar, andvitamin Aand D derivatives, or systemic treatments such asmethotrexateandSoriatane.^[116]

Herpetology

Reptilesneed UVB for biosynthesis of vitamin D, and other metabolic processes.^[117]Specificallycholecalciferol(vitamin D3), which is needed for basic cellular / neural functioning as well as the utilization of calcium for bone and egg production.^{[citation needed]}The UVA wavelength is also visible to many reptiles and might play a significant role in their ability survive in the wild as well as in visual communication between individuals.^{[citation needed]}Therefore, in a typical reptile enclosure, a fluorescent UV a/b source (at the proper strength / spectrum for the species), must be available for many^[which?]captive species to survive. Simple supplementation withcholecalciferol(Vitamin D3) will not be enough as there's a complete biosynthetic pathway^[which?]that is "leapfrogged" (risks of possible overdoses), the intermediate molecules and metabolites^[which?]also play important functions in the animals health.^{[citation needed]}Natural sunlight in the right levels is always going to be superior to artificial sources, but this might not be possible for keepers in different parts of the world.^{[citation needed]}

It is a known problem that high levels of output of the UVa part of the spectrum can both cause cellular and DNA damage to sensitive parts of their bodies – especially the eyes where blindness is the result of an improper UVa/b source use and placementphotokeratitis.^{[citation needed]}For many keepers there must also be a provision for an adequate heat source this has resulted in the marketing of heat and light "combination" products.^{[citation needed]}Keepers should be careful of these "combination" light/ heat and UVa/b generators, they typically emit high levels of UVa with lower levels of UVb that are set and difficult to control so that animals can have their needs met.^{[citation needed]}A better strategy is to use individual sources of these elements and so they can be placed and controlled by the keepers for the max benefit of the animals.^[118]

Evolutionary significance

The evolution of early reproductiveproteinsandenzymesis attributed in modern models ofevolutionary theoryto ultraviolet radiation. UVB causesthyminebase pairs next to each other in genetic sequences to bond together intothymine dimers,a disruption in the strand that reproductive enzymes cannot copy. This leads toframeshiftingduring genetic replication andprotein synthesis,usually killing the cell. Before formation of the UV-blocking ozone layer, when earlyprokaryotesapproached the surface of the ocean, they almost invariably died out. The few that survived had developed enzymes that monitored the genetic material and removedthymine dimersbynucleotide excision repairenzymes. Many enzymes and proteins involved in modernmitosisandmeiosisare similar to repair enzymes, and are believed to be evolved modifications of the enzymes originally used to overcome DNA damages caused by UV.^[119]

Photobiology

Photobiology is the scientific study of the beneficial and harmful interactions of non-ionizing radiation in living organisms, conventionally demarcated around 10 eV, the first ionization energy of oxygen. UV ranges roughly from 3 to 30 eV in energy. Hence photobiology entertains some, but not all, of the UV spectrum.

References

^"Reference Solar Spectral Irradiance: Air Mass 1.5".Archived fromthe originalon 27 January 2011.Retrieved12 November2009.
^Haigh, Joanna D. (2007)."The Sun and the Earth's Climate: Absorption of solar spectral radiation by the atmosphere".Living Reviews in Solar Physics.4(2): 2.Bibcode:2007LRSP....4....2H.doi:10.12942/lrsp-2007-2.
^Wacker, Matthias; Holick, Michael F. (1 January 2013)."Sunlight and Vitamin D".Dermato-endocrinology.5(1): 51–108.doi:10.4161/derm.24494.ISSN 1938-1972.PMC3897598.PMID 24494042.
^^a ^bDavid Hambling (29 May 2002)."Let the light shine in".The Guardian.Archivedfrom the original on 23 November 2014.Retrieved2 January2015.
^Cronin, Thomas W.; Bok, Michael J. (15 September 2016)."Photoreception and vision in the ultraviolet".Journal of Experimental Biology.219(18): 2790–2801.doi:10.1242/jeb.128769.hdl:11603/13303.ISSN 1477-9145.PMID 27655820.S2CID 22365933.Archivedfrom the original on 24 June 2022.Retrieved23 June2022.
^M A Mainster (2006)."Violet and blue light blocking intraocular lenses: photoprotection versus photoreception".British Journal of Ophthalmology.90(6): 784–792.doi:10.1136/bjo.2005.086553.PMC1860240.PMID 16714268.
^Lynch, David K.; Livingston, William Charles (2001).Color and Light in Nature(2nd ed.). Cambridge:Cambridge University Press.p. 231.ISBN 978-0-521-77504-5.Archivedfrom the original on 31 December 2013.Retrieved12 October2013.Limits of the eye's overall range of sensitivity extends from about 310 to 1050 nanometers
^Dash, Madhab Chandra; Dash, Satya Prakash (2009).Fundamentals of Ecology 3E.Tata McGraw-Hill Education. p. 213.ISBN 978-1-259-08109-5.Archivedfrom the original on 31 December 2013.Retrieved18 October2013.Normally the human eye responds to light rays from 390 to 760 nm. This can be extended to a range of 310 to 1,050 nm under artificial conditions.
^Bennington-Castro, Joseph (22 November 2013)."Want ultraviolet vision? You're going to need smaller eyes".Gizmodo.Archivedfrom the original on 7 May 2016.
^Hunt, D. M.; Carvalho, L. S.; Cowing, J. A.; Davies, W. L. (2009)."Evolution and spectral tuning of visual pigments in birds and mammals".Philosophical Transactions of the Royal Society B: Biological Sciences.364(1531): 2941–2955.doi:10.1098/rstb.2009.0044.ISSN 0962-8436.PMC2781856.PMID 19720655.
^"On a new Imponderable Substance and on a Class of Chemical Rays analogous to the rays of Dark Heat", J.W. Draper, The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science, 1842, LXXX, pp.453–461
^"Description of the Tithonometer", J.W. Draper, The Practical Mechanic and Engineer's Magazine, January 1844, pp.122–127
^Beeson, Steven; Mayer, James W (23 October 2007). "12.2.2 Discoveries beyond the visible".Patterns of light: chasing the spectrum from Aristotle to LEDs.New York: Springer. p. 149.ISBN 978-0-387-75107-8.
^ Hockberger, Philip E. (2002). "A history of ultraviolet photobiology for humans, animals and microorganisms".Photochem. Photobiol.76(6): 561–79.doi:10.1562/0031-8655(2002)0760561AHOUPF2.0.CO2.PMID 12511035.S2CID 222100404.
^James Bolton, Christine Colton,The Ultraviolet Disinfection Handbook,American Water Works Association, 2008ISBN 978 1 58321 584 5,pp. 3–4
^Theozone layeralso protects living beings from this. Lyman, T. (1914)."Victor Schumann".The Astrophysical Journal.38:1–4.Bibcode:1914ApJ....39....1L.doi:10.1086/142050.
^ "ISO 21348 Definitions of Solar Irradiance Spectral Categories"(PDF).Space Weather (spacewx.com).Archived fromthe original(PDF)on 29 October 2013.Retrieved25 August2013.
^ Gullikson, E.M.; Korde, R.; Canfield, L.R.; Vest, R.E. (1996)."Stable silicon photodiodes for absolute intensity measurements in the VUV and soft X-ray regions"(PDF).Journal of Electron Spectroscopy and Related Phenomena.80:313–316.Bibcode:1996JESRP..80..313G.doi:10.1016/0368-2048(96)02983-0.Archived fromthe original(PDF)on 9 January 2009.Retrieved8 November2011.
^ Bally, John; Reipurth, Bo (2006).The Birth of Stars and Planets.Cambridge University Press. p. 177.
^ Bark, Yu B.; Barkhudarov, E.M.; Kozlov, Yu N.; Kossyi, I.A.; Silakov, V.P.; Taktakishvili, M.I.; Temchin, S.M. (2000). "Slipping surface discharge as a source of hard UV radiation".Journal of Physics D: Applied Physics.33(7): 859.Bibcode:2000JPhD...33..859B.doi:10.1088/0022-3727/33/7/317.S2CID 250819933.
^"Solar radiation"(PDF).Archived(PDF)from the original on 1 November 2012.
^"Introduction to Solar Radiation".newport.com.Archivedfrom the original on 29 October 2013.
^"Reference Solar Spectral Irradiance: Air Mass 1.5".Archivedfrom the original on 28 September 2013.Retrieved12 November2009.
^Understanding UVA and UVB,archivedfrom the original on 1 May 2012,retrieved30 April2012
^Hormone-controlled UV-B responses in plants,archived fromthe originalon 8 July 2016
^Calbó, Josep; Pagès, David; González, Josep-Abel (2005). "Empirical studies of cloud effects on UV radiation: A review".Reviews of Geophysics.43(2). RG2002.Bibcode:2005RvGeo..43.2002C.doi:10.1029/2004RG000155.hdl:10256/8464.ISSN 1944-9208.S2CID 26285358.
^Burnett, M. E.; Wang, S. Q. (2011)."Current sunscreen controversies: a critical review".Photodermatology, Photoimmunology & Photomedicine.27(2): 58–67.doi:10.1111/j.1600-0781.2011.00557.x.PMID 21392107.S2CID 29173997.
^"Soda Lime Glass Transmission Curve".Archived fromthe originalon 27 March 2012.Retrieved20 January2012.
^"B270-Superwite Glass Transmission Curve".Präzisions Glas & Optik.Archivedfrom the original on 9 July 2017.Retrieved13 January2017.
^"Selected Float Glass Transmission Curve".Präzisions Glas & Optik.Archivedfrom the original on 19 October 2015.Retrieved13 January2017.
^^a ^bMoehrle, Matthias; Soballa, Martin; Korn, Manfred (2003). "UV exposure in cars".Photodermatology, Photoimmunology & Photomedicine.19(4): 175–181.doi:10.1034/j.1600-0781.2003.00031.x.ISSN 1600-0781.PMID 12925188.S2CID 37208948.
^"Optical Materials".Newport Corporation.Archivedfrom the original on 11 June 2020.Retrieved14 June2020.
^ "Insect-O-Cutor"(PDF).Archived(PDF)from the original on 4 June 2013.
^Rodrigues, Sueli; Fernandes, Fabiano Andre Narciso (18 May 2012).Advances in Fruit Processing Technologies.CRC Press. p. 5.ISBN 978-1-4398-5153-1.Archivedfrom the original on 5 March 2023.Retrieved22 October2022.
^ Klose, Jules Z.; Bridges, J. Mervin; Ott, William R. (June 1987).Radiometric standards in the V‑UV(PDF).NBS Measurement Services (Report). NBS Special Publication. U.S.National Institute of Standards and Technology.250–3.Archived(PDF)from the original on 11 June 2016.
^"What is the difference between 365 nm and 395 nm UV LED lights?".waveformlighting.com.Archivedfrom the original on 22 May 2021.Retrieved27 October2020.
^ Boyce, J.M. (2016)."Modern technologies for improving cleaning and disinfection of environmental surfaces in hospitals".Antimicrobial Resistance and Infection Control.5:10.doi:10.1186/s13756-016-0111-x.PMC4827199.PMID 27069623.
^^a ^b "Ultraviolet germicidal irradiation"(PDF).University of Liverpool.p. 3. Archived fromthe original(PDF)on 6 August 2016.
^ "UV‑C LEDs Enhance Chromatography Applications".GEN Eng News.Archivedfrom the original on 4 November 2016.
^"UV laser diode: 375 nm center wavelength".Thorlabs.Product Catalog. United States / Germany.Archivedfrom the original on 15 December 2014.Retrieved14 December2014.
^ Marshall, Chris (1996).A simple, reliable ultraviolet laser: The Ce:LiSAF(Report).Lawrence Livermore National Laboratory.Archived fromthe originalon 20 September 2008.Retrieved11 January2008.
^^a ^b ^cStrauss, C.E.M.; Funk, D.J. (1991)."Broadly tunable difference-frequency generation of VUV using two-photon resonances in H₂and Kr ".Optics Letters.16(15): 1192–4.Bibcode:1991OptL...16.1192S.doi:10.1364/ol.16.001192.PMID 19776917.Archivedfrom the original on 29 May 2024.Retrieved11 April2021.
^ Xiong, Bo; Chang, Yih-Chung; Ng, Cheuk-Yiu (2017)."Quantum-state-selected integral cross sections for the charge transfer collision of $O + 2 (a 4 Π u 5/2,3/2,1/2,-1/2 :$ $v + =1-2; J +)$ $[ O + 2 (X 2 Π g 3/2,1/2 :$ $v + =22-23; J +) ] + Ar$ at center-of-mass collision energies of 0.05–10.00 eV ".Phys. Chem. Chem. Phys.19(43): 29057–29067.Bibcode:2017PCCP...1929057X.doi:10.1039/C7CP04886F.PMID 28920600.Archivedfrom the original on 15 November 2017.
^ "E‑UV nudges toward 10 nm".EE Times.Archived fromthe originalon 15 October 2014.Retrieved26 September2014.
^Sivamani, R.K.; Crane, L.A.; Dellavalle, R.P. (April 2009)."The benefits and risks of ultraviolet tanning and its alternatives: The role of prudent sun exposure".Dermatologic Clinics.27(2): 149–154.doi:10.1016/j.det.2008.11.008.PMC2692214.PMID 19254658.
^Wacker, Matthias; Holick, Michael F. (1 January 2013)."Sunlight and Vitamin D".Dermato-endocrinology.5(1): 51–108.doi:10.4161/derm.24494.ISSN 1938-1972.PMC3897598.PMID 24494042.
^^a ^bThe known health effects of UV: Ultraviolet radiation and the INTERSUN Programme(Report). World Health Organization. Archived fromthe originalon 16 October 2016.
^Lamberg-Allardt, Christel (1 September 2006)."Vitamin D in foods and as supplements".Progress in Biophysics and Molecular Biology.92(1): 33–38.doi:10.1016/j.pbiomolbio.2006.02.017.ISSN 0079-6107.PMID 16618499.
^Korb, Alex (17 November 2011)."Boosting your serotonin activity".Psychology Today.Archived fromthe originalon 1 August 2017.
^Young, S.N. (2007)."How to increase serotonin in the human brain without drugs".Journal of Psychiatry and Neuroscience.32(6): 394–399.PMC2077351.PMID 18043762.
^Juzeniene, Asta; Moan, Johan (27 October 2014)."Beneficial effects of UV radiation other than via vitamin D production".Dermato-Endocrinology.4(2): 109–117.doi:10.4161/derm.20013.PMC3427189.PMID 22928066.
^"Health effects of ultraviolet radiation"Archived8 October 2016 at theWayback Machine.Government of Canada.
^Herzinger, T.; Funk, J.O.; Hillmer, K.; Eick, D.; Wolf, D.A.; Kind, P. (1995). "Ultraviolet B irradiation-induced G2 cell cycle arrest in human keratinocytes by inhibitory phosphorylation of the cdc2 cell cycle kinase".Oncogene.11(10): 2151–2156.PMID 7478536.
^Bhatia, Bhavnit K.; Bahr, Brooks A.; Murase, Jenny E. (2015)."Excimer laser therapy and narrowband ultraviolet B therapy for exfoliative cheilitis".International Journal of Women's Dermatology.1(2): 95–98.doi:10.1016/j.ijwd.2015.01.006.PMC5418752.PMID 28491966.
^Meyer-Rochow, Victor Benno (2000). "Risks, especially for the eye, emanating from the rise of solar UV-radiation in the Arctic and Antarctic regions".International Journal of Circumpolar Health.59(1): 38–51.PMID 10850006.
^"Health effects of UV radiation".World Health Organization. Archived fromthe originalon 17 March 2015.
^Ultraviolet Radiation Guide(PDF).Environmental Health Center (Report). Norfolk, Virginia: U.S.Navy. April 1992. Archived fromthe original(PDF)on 21 December 2019.Retrieved21 December2019.
^"What is ultraviolet (UV) radiation?".cancer.org.Archivedfrom the original on 3 April 2017.Retrieved11 June2017.
^ Torma, H.; Berne, B.; Vahlquist, A. (1988). "UV irradiation and topical vitamin A modulate retinol esterification in hairless mouse epidermis".Acta Derm. Venereol.68(4): 291–299.PMID 2459873.
^^a ^bBernstein C, Bernstein H, Payne CM, Garewal H (June 2002). "DNA repair / pro-apoptotic dual-role proteins in five major DNA repair pathways: Fail-safe protection against carcinogenesis".Mutat. Res.511(2): 145–78.Bibcode:2002MRRMR.511..145B.doi:10.1016/S1383-5742(02)00009-1.PMID 12052432.
^Davies, H.; Bignell, G.R.; Cox, C. (June 2002)."Mutations of theBRAFgene in human cancer "(PDF).Nature.417(6892): 949–954.Bibcode:2002Natur.417..949D.doi:10.1038/nature00766.PMID 12068308.S2CID3071547.Archived(PDF)from the original on 5 August 2020.Retrieved30 November2019.
^Weller, Richard (10 June 2015)."Shunning the sun may be killing you in more ways than you think".New Scientist.Archivedfrom the original on 9 June 2017.
^Hogan, C. Michael (25 May 2012) [November 12, 2010]."Sunlight".In Saundry, P.; Cleveland, C. (eds.).Encyclopedia of Earth.Archived fromthe originalon 19 October 2013.
^Svobodová AR, Galandáková A, Sianská J, et al. (January 2012). "DNA damage after acute exposure of mice skin to physiological doses of UVB and UVA light".Arch. Dermatol. Res.304(5): 407–412.doi:10.1007/s00403-012-1212-x.PMID 22271212.S2CID 20554266.
^Halliday GM, Byrne SN, Damian DL (December 2011). "Ultraviolet A radiation: Its role in immunosuppression and carcinogenesis".Semin. Cutan. Med. Surg.30(4): 214–21.doi:10.1016/j.sder.2011.08.002.PMID 22123419.
^^a ^bXu, C.; Green, Adele; Parisi, Alfio; Parsons, Peter G (2001). "Photosensitization of the sunscreen octyl p‑dimethylaminobenzoate b UV‑A in human melanocytes but not in keratinocytes".Photochemistry and Photobiology.73(6): 600–604.doi:10.1562/0031-8655(2001)073<0600:POTSOP>2.0.CO;2.PMID 11421064.S2CID 38706861.
^^a ^bKnowland, John; McKenzie, Edward A.; McHugh, Peter J.; Cridland, Nigel A. (1993). "Sunlight-induced mutagenicity of a common sunscreen ingredient".FEBS Letters.324(3): 309–313.Bibcode:1993FEBSL.324..309K.doi:10.1016/0014-5793(93)80141-G.PMID 8405372.S2CID 23853321.
^Chatelaine, E.; Gabard, B.; Surber, C. (2003)."Skin penetration and sun protection factor of five UV filters: Effect of the vehicle".Skin Pharmacol. Appl. Skin Physiol.16(1): 28–35.doi:10.1159/000068291(inactive 27 June 2024).PMID 12566826.S2CID 13458955.Archivedfrom the original on 27 December 2013.Retrieved26 December2013.{{cite journal}}:CS1 maint: DOI inactive as of June 2024 (link)
^Stephens TJ, Herndon JH, Colón LE, Gottschalk RW (February 2011). "The impact of natural sunlight exposure on the UV‑B – sun protection factor (UVB-SPF) and UVA protection factor (UVA-PF) of a UV‑A / UV‑B SPF 50 sunscreen".J. Drugs Dermatol.10(2): 150–155.PMID 21283919.
^Couteau C, Couteau O, Alami-El Boury S, Coiffard LJ (August 2011). "Sunscreen products: what do they protect us from?".Int. J. Pharm.415(1–2): 181–184.doi:10.1016/j.ijpharm.2011.05.071.PMID 21669263.
^Garland C, Garland F, Gorham E (1992)."Could sunscreens increase melanoma risk?".Am. J. Public Health.82(4): 614–615.doi:10.2105/AJPH.82.4.614.PMC1694089.PMID 1546792.
^Westerdahl J, Ingvar C, Masback A, Olsson H (2000)."Sunscreen use and malignant melanoma".International Journal of Cancer.87(1): 145–150.doi:10.1002/1097-0215(20000701)87:1<145::AID-IJC22>3.0.CO;2-3.PMID 10861466.
^Autier P, Dore JF, Schifflers E, et al. (1995). "Melanoma and use of sunscreens: An EORTC case control study in Germany, Belgium and France".Int. J. Cancer.61(6): 749–755.doi:10.1002/ijc.2910610602.PMID 7790106.S2CID 34941555.
^Weinstock, M. A. (1999)."Do sunscreens increase or decrease melanoma risk: An epidemiologic evaluation".Journal of Investigative Dermatology Symposium Proceedings.4(1): 97–100.PMID 10537017.Archivedfrom the original on 5 December 2022.Retrieved5 December2022.
^Vainio, H.; Bianchini, F. (2000)."Commentary: Cancer-preventive effects of sunscreens are uncertain".Scandinavian Journal of Work, Environment & Health.26(6): 529–531.doi:10.5271/sjweh.578.
^^a ^b ^cHanson, Kerry M.; Gratton, Enrico; Bardeen, Christopher J. (2006)."Sunscreen enhancement of UV-induced reactive oxygen species in the skin".Free Radical Biology and Medicine.41(8): 1205–1212.doi:10.1016/j.freeradbiomed.2006.06.011.PMID 17015167.S2CID 13999532.Archivedfrom the original on 6 August 2020.Retrieved6 September2018.
^Damiani, E.; Greci, L.; Parsons, R.; Knowland, J. (1999). "Nitroxide radicals protect DNA from damage when illuminated in vitro in the presence of dibenzoylmethane and a common sunscreen ingredient".Free Radic. Biol. Med.26(7–8): 809–816.doi:10.1016/S0891-5849(98)00292-5.PMID 10232823.
^§2 Photoaggravated disorders(PDF).European Dermatology Forum(Report). European guidelines for photodermatoses.Retrieved1 January2016.^{[permanent dead link]}
^Medscape: Porokeratosis Archived24 June 2021 at theWayback Machine.
^The known health effects of UV(Report). World Health Organization.Archivedfrom the original on 24 October 2016.
^"UV radiation".World Health Organization.Archivedfrom the original on 25 October 2016.
^What is UV radiation and how much does it increase with altitude?(Report). U.S.National Oceanographic and Atmospheric Administration.Archivedfrom the original on 3 January 2017.
^"Optical properties of lens materials".Optician Online.6 June 2005.Archivedfrom the original on 26 October 2016.
^"Classification of UV".SETi.Archivedfrom the original on 1 December 2019.Retrieved1 December2019.
"Applications".SETi.Archived from the original on 20 August 2008.Retrieved26 September2009.{{cite web}}:CS1 maint: unfit URL (link)
^"Ultraviolet Light, UV Rays, What is Ultraviolet, UV Light Bulbs, Fly Trap".Pestproducts.com.Archivedfrom the original on 8 October 2011.Retrieved8 November2011.
^ "The daytime UV inspection magazine".Corona.Archivedfrom the original on 1 August 2004.
^ Springer, E.; Almog, J.; Frank, A.; Ziv, Z.; Bergman, P.; Gui Quang, W. (1994). "Detection of dry bodily fluids by inherent short wavelength UV luminescence: Preliminary results".Forensic Sci. Int.66(2): 89–94.doi:10.1016/0379-0738(94)90332-8.PMID 8063277.
^ Fiedler, Anja; Benecke, Mark; et al."Detection of semen (human and boar) and saliva on fabrics by a very high-powered UV- / VIS-light source"(PDF).Bentham Science.Archived fromthe original(PDF)on 30 November 2012.Retrieved10 December2009.
^ "Digital photography of documents".wells-genealogy.org.uk. Archived fromthe originalon 19 September 2012.
^ "Defining" What is clean? "".Integrated cleaning and measurement. Healthy Facilities Institute. Archived fromthe originalon 21 September 2017.Retrieved24 June2017.
^"Non-destructive inspection: Seeing through the B‑52".afgsc.af.mil.U.S. Air Force.Archivedfrom the original on 16 November 2017.Retrieved24 June2017.
^ Escobar, David (20 April 2015)."Oxygen cleaning: A validated process is critical for safety".Valve Magazine.Archivedfrom the original on 15 November 2017.
^ Raj, Baldev; Jayakumar, T.; Thavasimuthu, M. (2002).Practical Non-destructive Testing.Woodhead Publishing. p. 10.ISBN 9781855736009.
^ "New investigation finds some hotels don't wash sheets between guests".House Beautiful.15 September 2016.Archivedfrom the original on 3 July 2017.
^ "What's hiding in your hotel room?".ABC News.17 November 2010.Archivedfrom the original on 22 July 2016.
^^a ^b ^c ^dLee, Brandon Chuan Yee; Lim, Fang Yee; Loh, Wei Hao; Ong, Say Leong; Hu, Jiangyong (January 2021)."Emerging Contaminants: An Overview of Recent Trends for Their Treatment and Management Using Light-Driven Processes".Water.13(17): 2340.doi:10.3390/w13172340.ISSN 2073-4441.
^ Battikha, N.E., ed. (2007).The Condensed Handbook of Measurement and Control(3rd ed.). ISA. pp. 65–66.ISBN 978-1-55617-995-2.
^ Fingas, Mervin, ed. (2011).Oil Spill Science and Technology.Elsevier. pp. 123–124.ISBN 978-1-85617-943-0.
^"What is an Excitation Emission Matrix (EEM)?".horiba.com.Archivedfrom the original on 10 July 2023.Retrieved10 July2023.
^Sierra, M.M.D.; Giovanela, M.; Parlanti, E.; Soriano-Sierra, E.J. (February 2005)."Fluorescence fingerprint of fulvic and humic acids from varied origins as viewed by single-scan and excitation/emission matrix techniques".Chemosphere.58(6): 715–733.Bibcode:2005Chmsp..58..715S.doi:10.1016/j.chemosphere.2004.09.038.ISSN 0045-6535.PMID 15621185.Archivedfrom the original on 29 May 2024.Retrieved10 July2023.
^"Deep UV Photoresists".Archived fromthe originalon 12 March 2006.
^R. V. Lapshin; A. P. Alekhin; A. G. Kirilenko; S. L. Odintsov; V. A. Krotkov (2010)."Vacuum ultraviolet smoothing of nanometer-scale asperities of poly(methyl methacrylate) surface".Journal of Surface Investigation. X-ray, Synchrotron and Neutron Techniques.4(1): 1–11.doi:10.1134/S1027451010010015.ISSN 1027-4510.S2CID 97385151.Archivedfrom the original on 9 September 2013.
^"The Importance of UV Light for Plants Cultivated Indoors".Best LED Grow Lights Info.11 June 2017.Archivedfrom the original on 30 July 2018.Retrieved24 June2017.
^Scott, K.J.; Wills, R.R.H.; Patterson, B.D. (1971). "Removal by ultra-violet lamp of ethylene and other hydrocarbons produced by bananas".Journal of the Science of Food and Agriculture.22(9): 496–7.Bibcode:1971JSFA...22..496S.doi:10.1002/jsfa.2740220916.
^Scott, KJ; Wills, RBH (1973). "Atmospheric pollutants destroyed in an ultra violet scrubber".Laboratory Practice.22(2): 103–6.PMID 4688707.
^Shorter, AJ; Scott, KJ (1986). "Removal of ethylene from air and low oxygen atmospheres with ultra violet radiation".Lebensm-Wiss U Technology.19:176–9.
^Chang, Kenneth (7 May 2020)."Scientists Consider Indoor Ultraviolet Light to Zap Coronavirus in the Air".The New York Times.Archivedfrom the original on 7 May 2020.Retrieved9 May2020.
^Welch, David; et al. (January 2018)."Far-UVC light: A new tool to control the spread of airborne-mediated microbial diseases".Scientific Reports.8(1): 2752.Bibcode:2018NatSR...8.2752W.doi:10.1038/s41598-018-21058-w.ISSN 2045-2322.PMC5807439.PMID 29426899.
^"Coming of Age UV-C LED Technology Update".wateronline.com.Archivedfrom the original on 20 April 2017.
^"Solar Water Disinfection".Sodis.ch. 2 April 2011. Archived fromthe originalon 31 August 2012.Retrieved8 November2011.
^"Video Demos".Archived fromthe originalon 19 December 2014.Retrieved27 November2014.
^Lorenzo-Leal, Ana C.; Tam, Wenxi; Kheyrandish, Ata; Mohseni, Madjid; Bach, Horacio (31 October 2023). Barbosa, Joana (ed.)."Antimicrobial Activity of Filtered Far-UVC Light (222 nm) against Different Pathogens".BioMed Research International.2023:1–8.doi:10.1155/2023/2085140.ISSN 2314-6141.PMC10630020.PMID 37942030.
^Devitt, George; Johnson, Peter B.; Hanrahan, Niall; Lane, Simon I. R.; Vidale, Magdalena C.; Sheth, Bhavwanti; Allen, Joel D.; Humbert, Maria V.; Spalluto, Cosma M.; Hervé, Rodolphe C.; Staples, Karl; West, Jonathan J.; Forster, Robert; Divecha, Nullin; McCormick, Christopher J.; Crispin, Max; Hempler, Nils; Malcolm, Graeme P. A.; Mahajan, Sumeet (2023)."Mechanisms of SARS-CoV-2 Inactivation Using UVC Laser Radiation".ACS Photonics.11(1): 42–52.doi:10.1021/acsphotonics.3c00828.PMC10797618.PMID 38249683.
^Silberglied, Robert E.; Taylor, Orley R. (1978). "Ultraviolet Reflection and Its Behavioral Role in the Courtship of the Sulfur Butterflies Colias eurytheme and C. philodice (Lepidoptera, Pieridae)".Behavioral Ecology and Sociobiology.3(3): 203–43.doi:10.1007/bf00296311.S2CID 38043008.
^Meyer-Rochow, V.B.; Järvilehto, M. (1997). "Ultraviolet colours in Pieris napi from northern and southern Finland: Arctic females are the brightest!".Naturwissenschaften.84(4): 165–168.Bibcode:1997NW.....84..165M.doi:10.1007/s001140050373.S2CID 46142866.
^ "UVB Phototherapy".National Psoriasis Foundation, USA. Archived fromthe original(php)on 22 June 2007.Retrieved23 September2007.
^Diehl, J. J. E.; Baines, F. M.; Heijboer, A. C.; van Leeuwen, J. P.; Kik, M.; Hendriks, W. H.; Oonincx, D. G. A. B. (February 2018)."A comparison of UVb compact lamps in enabling cutaneous vitamin D synthesis in growing bearded dragons".Journal of Animal Physiology and Animal Nutrition.102(1): 308–316.doi:10.1111/jpn.12728.PMID 28452197.S2CID 30124686.
^"Vitamin D and Ultraviolet Light – a remarkable process".UV Guide UK.Archivedfrom the original on 31 May 2016.Retrieved13 January2017.
^Margulis, Lynn&Sagan, Dorion(1986).Origins of Sex: Three Billion Years of Genetic Recombination(book).1. Yale University Press.ISBN 978-0-300-04619-9.Archivedfrom the original on 29 May 2024.Retrieved22 November2020.

External links

Media related toUltraviolet lightat Wikimedia Commons
The dictionary definition ofultravioletat Wiktionary

[1] "Reference Solar Spectral Irradiance: Air Mass 1.5".Archived fromthe originalon 27 January 2011.Retrieved12 November2009.

[2] Haigh, Joanna D. (2007)."The Sun and the Earth's Climate: Absorption of solar spectral radiation by the atmosphere".Living Reviews in Solar Physics.4(2): 2.Bibcode:2007LRSP....4....2H.doi:10.12942/lrsp-2007-2.

[3] Wacker, Matthias; Holick, Michael F. (1 January 2013)."Sunlight and Vitamin D".Dermato-endocrinology.5(1): 51–108.doi:10.4161/derm.24494.ISSN 1938-1972.PMC3897598.PMID 24494042.

[hambling-4] David Hambling (29 May 2002)."Let the light shine in".The Guardian.Archivedfrom the original on 23 November 2014.Retrieved2 January2015.

[5] Cronin, Thomas W.; Bok, Michael J. (15 September 2016)."Photoreception and vision in the ultraviolet".Journal of Experimental Biology.219(18): 2790–2801.doi:10.1242/jeb.128769.hdl:11603/13303.ISSN 1477-9145.PMID 27655820.S2CID 22365933.Archivedfrom the original on 24 June 2022.Retrieved23 June2022.

[6] M A Mainster (2006)."Violet and blue light blocking intraocular lenses: photoprotection versus photoreception".British Journal of Ophthalmology.90(6): 784–792.doi:10.1136/bjo.2005.086553.PMC1860240.PMID 16714268.

[LynchLivingston2001-7] Lynch, David K.; Livingston, William Charles (2001).Color and Light in Nature(2nd ed.). Cambridge:Cambridge University Press.p. 231.ISBN 978-0-521-77504-5.Archivedfrom the original on 31 December 2013.Retrieved12 October2013.Limits of the eye's overall range of sensitivity extends from about 310 to 1050 nanometers

[Dash2009-8] Dash, Madhab Chandra; Dash, Satya Prakash (2009).Fundamentals of Ecology 3E.Tata McGraw-Hill Education. p. 213.ISBN 978-1-259-08109-5.Archivedfrom the original on 31 December 2013.Retrieved18 October2013.Normally the human eye responds to light rays from 390 to 760 nm. This can be extended to a range of 310 to 1,050 nm under artificial conditions.

[9] Bennington-Castro, Joseph (22 November 2013)."Want ultraviolet vision? You're going to need smaller eyes".Gizmodo.Archivedfrom the original on 7 May 2016.

[HuntCarvalho2009-10] Hunt, D. M.; Carvalho, L. S.; Cowing, J. A.; Davies, W. L. (2009)."Evolution and spectral tuning of visual pigments in birds and mammals".Philosophical Transactions of the Royal Society B: Biological Sciences.364(1531): 2941–2955.doi:10.1098/rstb.2009.0044.ISSN 0962-8436.PMC2781856.PMID 19720655.

[11] "On a new Imponderable Substance and on a Class of Chemical Rays analogous to the rays of Dark Heat", J.W. Draper, The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science, 1842, LXXX, pp.453–461

[12] "Description of the Tithonometer", J.W. Draper, The Practical Mechanic and Engineer's Magazine, January 1844, pp.122–127

[13] Beeson, Steven; Mayer, James W (23 October 2007). "12.2.2 Discoveries beyond the visible".Patterns of light: chasing the spectrum from Aristotle to LEDs.New York: Springer. p. 149.ISBN 978-0-387-75107-8.

[hockberger-14] Hockberger, Philip E. (2002). "A history of ultraviolet photobiology for humans, animals and microorganisms".Photochem. Photobiol.76(6): 561–79.doi:10.1562/0031-8655(2002)0760561AHOUPF2.0.CO2.PMID 12511035.S2CID 222100404.

[15] James Bolton, Christine Colton,The Ultraviolet Disinfection Handbook,American Water Works Association, 2008ISBN 978 1 58321 584 5,pp. 3–4

[Lyman-16] Theozone layeralso protects living beings from this. Lyman, T. (1914)."Victor Schumann".The Astrophysical Journal.38:1–4.Bibcode:1914ApJ....39....1L.doi:10.1086/142050.

[17] "ISO 21348 Definitions of Solar Irradiance Spectral Categories"(PDF).Space Weather (spacewx.com).Archived fromthe original(PDF)on 29 October 2013.Retrieved25 August2013.

[18] Gullikson, E.M.; Korde, R.; Canfield, L.R.; Vest, R.E. (1996)."Stable silicon photodiodes for absolute intensity measurements in the VUV and soft X-ray regions"(PDF).Journal of Electron Spectroscopy and Related Phenomena.80:313–316.Bibcode:1996JESRP..80..313G.doi:10.1016/0368-2048(96)02983-0.Archived fromthe original(PDF)on 9 January 2009.Retrieved8 November2011.

[19] Bally, John; Reipurth, Bo (2006).The Birth of Stars and Planets.Cambridge University Press. p. 177.

[20] Bark, Yu B.; Barkhudarov, E.M.; Kozlov, Yu N.; Kossyi, I.A.; Silakov, V.P.; Taktakishvili, M.I.; Temchin, S.M. (2000). "Slipping surface discharge as a source of hard UV radiation".Journal of Physics D: Applied Physics.33(7): 859.Bibcode:2000JPhD...33..859B.doi:10.1088/0022-3727/33/7/317.S2CID 250819933.

[21] "Solar radiation"(PDF).Archived(PDF)from the original on 1 November 2012.

[22] "Introduction to Solar Radiation".newport.com.Archivedfrom the original on 29 October 2013.

[23] "Reference Solar Spectral Irradiance: Air Mass 1.5".Archivedfrom the original on 28 September 2013.Retrieved12 November2009.

[Skin_Cancer_Foundation-24] Understanding UVA and UVB,archivedfrom the original on 1 May 2012,retrieved30 April2012

[Vanhaelewyn_et_al._2016-25] Hormone-controlled UV-B responses in plants,archived fromthe originalon 8 July 2016

[26] Calbó, Josep; Pagès, David; González, Josep-Abel (2005). "Empirical studies of cloud effects on UV radiation: A review".Reviews of Geophysics.43(2). RG2002.Bibcode:2005RvGeo..43.2002C.doi:10.1029/2004RG000155.hdl:10256/8464.ISSN 1944-9208.S2CID 26285358.

[27] Burnett, M. E.; Wang, S. Q. (2011)."Current sunscreen controversies: a critical review".Photodermatology, Photoimmunology & Photomedicine.27(2): 58–67.doi:10.1111/j.1600-0781.2011.00557.x.PMID 21392107.S2CID 29173997.

[28] "Soda Lime Glass Transmission Curve".Archived fromthe originalon 27 March 2012.Retrieved20 January2012.

[29] "B270-Superwite Glass Transmission Curve".Präzisions Glas & Optik.Archivedfrom the original on 9 July 2017.Retrieved13 January2017.

[30] "Selected Float Glass Transmission Curve".Präzisions Glas & Optik.Archivedfrom the original on 19 October 2015.Retrieved13 January2017.

[UV_exposure_in_cars-31] Moehrle, Matthias; Soballa, Martin; Korn, Manfred (2003). "UV exposure in cars".Photodermatology, Photoimmunology & Photomedicine.19(4): 175–181.doi:10.1034/j.1600-0781.2003.00031.x.ISSN 1600-0781.PMID 12925188.S2CID 37208948.

[32] "Optical Materials".Newport Corporation.Archivedfrom the original on 11 June 2020.Retrieved14 June2020.

[33] "Insect-O-Cutor"(PDF).Archived(PDF)from the original on 4 June 2013.

[34] Rodrigues, Sueli; Fernandes, Fabiano Andre Narciso (18 May 2012).Advances in Fruit Processing Technologies.CRC Press. p. 5.ISBN 978-1-4398-5153-1.Archivedfrom the original on 5 March 2023.Retrieved22 October2022.

[35] Klose, Jules Z.; Bridges, J. Mervin; Ott, William R. (June 1987).Radiometric standards in the V‑UV(PDF).NBS Measurement Services (Report). NBS Special Publication. U.S.National Institute of Standards and Technology.250–3.Archived(PDF)from the original on 11 June 2016.

[36] "What is the difference between 365 nm and 395 nm UV LED lights?".waveformlighting.com.Archivedfrom the original on 22 May 2021.Retrieved27 October2020.

[37] Boyce, J.M. (2016)."Modern technologies for improving cleaning and disinfection of environmental surfaces in hospitals".Antimicrobial Resistance and Infection Control.5:10.doi:10.1186/s13756-016-0111-x.PMC4827199.PMID 27069623.

[Liverpool,_UVGI-38] "Ultraviolet germicidal irradiation"(PDF).University of Liverpool.p. 3. Archived fromthe original(PDF)on 6 August 2016.

[39] "UV‑C LEDs Enhance Chromatography Applications".GEN Eng News.Archivedfrom the original on 4 November 2016.

[40] "UV laser diode: 375 nm center wavelength".Thorlabs.Product Catalog. United States / Germany.Archivedfrom the original on 15 December 2014.Retrieved14 December2014.

[Marshall1996-41] Marshall, Chris (1996).A simple, reliable ultraviolet laser: The Ce:LiSAF(Report).Lawrence Livermore National Laboratory.Archived fromthe originalon 20 September 2008.Retrieved11 January2008.

[straussfunk-42] Strauss, C.E.M.; Funk, D.J. (1991)."Broadly tunable difference-frequency generation of VUV using two-photon resonances in H₂and Kr ".Optics Letters.16(15): 1192–4.Bibcode:1991OptL...16.1192S.doi:10.1364/ol.16.001192.PMID 19776917.Archivedfrom the original on 29 May 2024.Retrieved11 April2021.

[O2Ar-43] Xiong, Bo; Chang, Yih-Chung; Ng, Cheuk-Yiu (2017)."Quantum-state-selected integral cross sections for the charge transfer collision of $O + 2 (a 4 Π u 5/2,3/2,1/2,-1/2 :$ $v + =1-2; J +)$ $[ O + 2 (X 2 Π g 3/2,1/2 :$ $v + =22-23; J +) ] + Ar$ at center-of-mass collision energies of 0.05–10.00 eV ".Phys. Chem. Chem. Phys.19(43): 29057–29067.Bibcode:2017PCCP...1929057X.doi:10.1039/C7CP04886F.PMID 28920600.Archivedfrom the original on 15 November 2017.

[44] "E‑UV nudges toward 10 nm".EE Times.Archived fromthe originalon 15 October 2014.Retrieved26 September2014.

[sivamani-45] Sivamani, R.K.; Crane, L.A.; Dellavalle, R.P. (April 2009)."The benefits and risks of ultraviolet tanning and its alternatives: The role of prudent sun exposure".Dermatologic Clinics.27(2): 149–154.doi:10.1016/j.det.2008.11.008.PMC2692214.PMID 19254658.

[46] Wacker, Matthias; Holick, Michael F. (1 January 2013)."Sunlight and Vitamin D".Dermato-endocrinology.5(1): 51–108.doi:10.4161/derm.24494.ISSN 1938-1972.PMC3897598.PMID 24494042.

[who.int-47] The known health effects of UV: Ultraviolet radiation and the INTERSUN Programme(Report). World Health Organization. Archived fromthe originalon 16 October 2016.

[48] Lamberg-Allardt, Christel (1 September 2006)."Vitamin D in foods and as supplements".Progress in Biophysics and Molecular Biology.92(1): 33–38.doi:10.1016/j.pbiomolbio.2006.02.017.ISSN 0079-6107.PMID 16618499.

[49] Korb, Alex (17 November 2011)."Boosting your serotonin activity".Psychology Today.Archived fromthe originalon 1 August 2017.

[50] Young, S.N. (2007)."How to increase serotonin in the human brain without drugs".Journal of Psychiatry and Neuroscience.32(6): 394–399.PMC2077351.PMID 18043762.

[51] Juzeniene, Asta; Moan, Johan (27 October 2014)."Beneficial effects of UV radiation other than via vitamin D production".Dermato-Endocrinology.4(2): 109–117.doi:10.4161/derm.20013.PMC3427189.PMID 22928066.

[52] "Health effects of ultraviolet radiation"Archived8 October 2016 at theWayback Machine.Government of Canada.

[53] Herzinger, T.; Funk, J.O.; Hillmer, K.; Eick, D.; Wolf, D.A.; Kind, P. (1995). "Ultraviolet B irradiation-induced G2 cell cycle arrest in human keratinocytes by inhibitory phosphorylation of the cdc2 cell cycle kinase".Oncogene.11(10): 2151–2156.PMID 7478536.

[54] Bhatia, Bhavnit K.; Bahr, Brooks A.; Murase, Jenny E. (2015)."Excimer laser therapy and narrowband ultraviolet B therapy for exfoliative cheilitis".International Journal of Women's Dermatology.1(2): 95–98.doi:10.1016/j.ijwd.2015.01.006.PMC5418752.PMID 28491966.

[Meyer-Rochow_2000-55] Meyer-Rochow, Victor Benno (2000). "Risks, especially for the eye, emanating from the rise of solar UV-radiation in the Arctic and Antarctic regions".International Journal of Circumpolar Health.59(1): 38–51.PMID 10850006.

[56] "Health effects of UV radiation".World Health Organization. Archived fromthe originalon 17 March 2015.

[57] Ultraviolet Radiation Guide(PDF).Environmental Health Center (Report). Norfolk, Virginia: U.S.Navy. April 1992. Archived fromthe original(PDF)on 21 December 2019.Retrieved21 December2019.

[58] "What is ultraviolet (UV) radiation?".cancer.org.Archivedfrom the original on 3 April 2017.Retrieved11 June2017.

[59] Torma, H.; Berne, B.; Vahlquist, A. (1988). "UV irradiation and topical vitamin A modulate retinol esterification in hairless mouse epidermis".Acta Derm. Venereol.68(4): 291–299.PMID 2459873.

[autogenerated145-60] Bernstein C, Bernstein H, Payne CM, Garewal H (June 2002). "DNA repair / pro-apoptotic dual-role proteins in five major DNA repair pathways: Fail-safe protection against carcinogenesis".Mutat. Res.511(2): 145–78.Bibcode:2002MRRMR.511..145B.doi:10.1016/S1383-5742(02)00009-1.PMID 12052432.

[Davies-61] Davies, H.; Bignell, G.R.; Cox, C. (June 2002)."Mutations of theBRAFgene in human cancer "(PDF).Nature.417(6892): 949–954.Bibcode:2002Natur.417..949D.doi:10.1038/nature00766.PMID 12068308.S2CID3071547.Archived(PDF)from the original on 5 August 2020.Retrieved30 November2019.

[NS-62] Weller, Richard (10 June 2015)."Shunning the sun may be killing you in more ways than you think".New Scientist.Archivedfrom the original on 9 June 2017.

[63] Hogan, C. Michael (25 May 2012) [November 12, 2010]."Sunlight".In Saundry, P.; Cleveland, C. (eds.).Encyclopedia of Earth.Archived fromthe originalon 19 October 2013.

[64] Svobodová AR, Galandáková A, Sianská J, et al. (January 2012). "DNA damage after acute exposure of mice skin to physiological doses of UVB and UVA light".Arch. Dermatol. Res.304(5): 407–412.doi:10.1007/s00403-012-1212-x.PMID 22271212.S2CID 20554266.

[65] Halliday GM, Byrne SN, Damian DL (December 2011). "Ultraviolet A radiation: Its role in immunosuppression and carcinogenesis".Semin. Cutan. Med. Surg.30(4): 214–21.doi:10.1016/j.sder.2011.08.002.PMID 22123419.

[Parsons-66] Xu, C.; Green, Adele; Parisi, Alfio; Parsons, Peter G (2001). "Photosensitization of the sunscreen octyl p‑dimethylaminobenzoate b UV‑A in human melanocytes but not in keratinocytes".Photochemistry and Photobiology.73(6): 600–604.doi:10.1562/0031-8655(2001)073<0600:POTSOP>2.0.CO;2.PMID 11421064.S2CID 38706861.

[Knowland1993-67] Knowland, John; McKenzie, Edward A.; McHugh, Peter J.; Cridland, Nigel A. (1993). "Sunlight-induced mutagenicity of a common sunscreen ingredient".FEBS Letters.324(3): 309–313.Bibcode:1993FEBSL.324..309K.doi:10.1016/0014-5793(93)80141-G.PMID 8405372.S2CID 23853321.

[68] Chatelaine, E.; Gabard, B.; Surber, C. (2003)."Skin penetration and sun protection factor of five UV filters: Effect of the vehicle".Skin Pharmacol. Appl. Skin Physiol.16(1): 28–35.doi:10.1159/000068291(inactive 27 June 2024).PMID 12566826.S2CID 13458955.Archivedfrom the original on 27 December 2013.Retrieved26 December2013.{{cite journal}}:CS1 maint: DOI inactive as of June 2024 (link)

[69] Stephens TJ, Herndon JH, Colón LE, Gottschalk RW (February 2011). "The impact of natural sunlight exposure on the UV‑B – sun protection factor (UVB-SPF) and UVA protection factor (UVA-PF) of a UV‑A / UV‑B SPF 50 sunscreen".J. Drugs Dermatol.10(2): 150–155.PMID 21283919.

[70] Couteau C, Couteau O, Alami-El Boury S, Coiffard LJ (August 2011). "Sunscreen products: what do they protect us from?".Int. J. Pharm.415(1–2): 181–184.doi:10.1016/j.ijpharm.2011.05.071.PMID 21669263.

[Garland-71] Garland C, Garland F, Gorham E (1992)."Could sunscreens increase melanoma risk?".Am. J. Public Health.82(4): 614–615.doi:10.2105/AJPH.82.4.614.PMC1694089.PMID 1546792.

[Westerdahl2000-72] Westerdahl J, Ingvar C, Masback A, Olsson H (2000)."Sunscreen use and malignant melanoma".International Journal of Cancer.87(1): 145–150.doi:10.1002/1097-0215(20000701)87:1<145::AID-IJC22>3.0.CO;2-3.PMID 10861466.

[Autier-73] Autier P, Dore JF, Schifflers E, et al. (1995). "Melanoma and use of sunscreens: An EORTC case control study in Germany, Belgium and France".Int. J. Cancer.61(6): 749–755.doi:10.1002/ijc.2910610602.PMID 7790106.S2CID 34941555.

[Weinstock-74] Weinstock, M. A. (1999)."Do sunscreens increase or decrease melanoma risk: An epidemiologic evaluation".Journal of Investigative Dermatology Symposium Proceedings.4(1): 97–100.PMID 10537017.Archivedfrom the original on 5 December 2022.Retrieved5 December2022.

[Vainio-75] Vainio, H.; Bianchini, F. (2000)."Commentary: Cancer-preventive effects of sunscreens are uncertain".Scandinavian Journal of Work, Environment & Health.26(6): 529–531.doi:10.5271/sjweh.578.

[Hanson-76] Hanson, Kerry M.; Gratton, Enrico; Bardeen, Christopher J. (2006)."Sunscreen enhancement of UV-induced reactive oxygen species in the skin".Free Radical Biology and Medicine.41(8): 1205–1212.doi:10.1016/j.freeradbiomed.2006.06.011.PMID 17015167.S2CID 13999532.Archivedfrom the original on 6 August 2020.Retrieved6 September2018.

[Damiani1999-77] Damiani, E.; Greci, L.; Parsons, R.; Knowland, J. (1999). "Nitroxide radicals protect DNA from damage when illuminated in vitro in the presence of dibenzoylmethane and a common sunscreen ingredient".Free Radic. Biol. Med.26(7–8): 809–816.doi:10.1016/S0891-5849(98)00292-5.PMID 10232823.

[euroderm-78] §2 Photoaggravated disorders(PDF).European Dermatology Forum(Report). European guidelines for photodermatoses.Retrieved1 January2016.^{[permanent dead link]}

[Medscape-79] Medscape: Porokeratosis Archived24 June 2021 at theWayback Machine.

[80] The known health effects of UV(Report). World Health Organization.Archivedfrom the original on 24 October 2016.

[81] "UV radiation".World Health Organization.Archivedfrom the original on 25 October 2016.

[82] What is UV radiation and how much does it increase with altitude?(Report). U.S.National Oceanographic and Atmospheric Administration.Archivedfrom the original on 3 January 2017.

[83] "Optical properties of lens materials".Optician Online.6 June 2005.Archivedfrom the original on 26 October 2016.

[84] "Classification of UV".SETi.Archivedfrom the original on 1 December 2019.Retrieved1 December2019.
"Applications".SETi.Archived from the original on 20 August 2008.Retrieved26 September2009.{{cite web}}:CS1 maint: unfit URL (link)

[85] "Ultraviolet Light, UV Rays, What is Ultraviolet, UV Light Bulbs, Fly Trap".Pestproducts.com.Archivedfrom the original on 8 October 2011.Retrieved8 November2011.

[86] "The daytime UV inspection magazine".Corona.Archivedfrom the original on 1 August 2004.

[87] Springer, E.; Almog, J.; Frank, A.; Ziv, Z.; Bergman, P.; Gui Quang, W. (1994). "Detection of dry bodily fluids by inherent short wavelength UV luminescence: Preliminary results".Forensic Sci. Int.66(2): 89–94.doi:10.1016/0379-0738(94)90332-8.PMID 8063277.

[88] Fiedler, Anja; Benecke, Mark; et al."Detection of semen (human and boar) and saliva on fabrics by a very high-powered UV- / VIS-light source"(PDF).Bentham Science.Archived fromthe original(PDF)on 30 November 2012.Retrieved10 December2009.

[89] "Digital photography of documents".wells-genealogy.org.uk. Archived fromthe originalon 19 September 2012.

[90] "Defining" What is clean? "".Integrated cleaning and measurement. Healthy Facilities Institute. Archived fromthe originalon 21 September 2017.Retrieved24 June2017.

[91] "Non-destructive inspection: Seeing through the B‑52".afgsc.af.mil.U.S. Air Force.Archivedfrom the original on 16 November 2017.Retrieved24 June2017.

[92] Escobar, David (20 April 2015)."Oxygen cleaning: A validated process is critical for safety".Valve Magazine.Archivedfrom the original on 15 November 2017.

[93] Raj, Baldev; Jayakumar, T.; Thavasimuthu, M. (2002).Practical Non-destructive Testing.Woodhead Publishing. p. 10.ISBN 9781855736009.

[94] "New investigation finds some hotels don't wash sheets between guests".House Beautiful.15 September 2016.Archivedfrom the original on 3 July 2017.

[95] "What's hiding in your hotel room?".ABC News.17 November 2010.Archivedfrom the original on 22 July 2016.

[ReferenceA-96] Lee, Brandon Chuan Yee; Lim, Fang Yee; Loh, Wei Hao; Ong, Say Leong; Hu, Jiangyong (January 2021)."Emerging Contaminants: An Overview of Recent Trends for Their Treatment and Management Using Light-Driven Processes".Water.13(17): 2340.doi:10.3390/w13172340.ISSN 2073-4441.

[97] Battikha, N.E., ed. (2007).The Condensed Handbook of Measurement and Control(3rd ed.). ISA. pp. 65–66.ISBN 978-1-55617-995-2.

[98] Fingas, Mervin, ed. (2011).Oil Spill Science and Technology.Elsevier. pp. 123–124.ISBN 978-1-85617-943-0.

[99] "What is an Excitation Emission Matrix (EEM)?".horiba.com.Archivedfrom the original on 10 July 2023.Retrieved10 July2023.

[100] Sierra, M.M.D.; Giovanela, M.; Parlanti, E.; Soriano-Sierra, E.J. (February 2005)."Fluorescence fingerprint of fulvic and humic acids from varied origins as viewed by single-scan and excitation/emission matrix techniques".Chemosphere.58(6): 715–733.Bibcode:2005Chmsp..58..715S.doi:10.1016/j.chemosphere.2004.09.038.ISSN 0045-6535.PMID 15621185.Archivedfrom the original on 29 May 2024.Retrieved10 July2023.

[101] "Deep UV Photoresists".Archived fromthe originalon 12 March 2006.

[102] R. V. Lapshin; A. P. Alekhin; A. G. Kirilenko; S. L. Odintsov; V. A. Krotkov (2010)."Vacuum ultraviolet smoothing of nanometer-scale asperities of poly(methyl methacrylate) surface".Journal of Surface Investigation. X-ray, Synchrotron and Neutron Techniques.4(1): 1–11.doi:10.1134/S1027451010010015.ISSN 1027-4510.S2CID 97385151.Archivedfrom the original on 9 September 2013.

[103] "The Importance of UV Light for Plants Cultivated Indoors".Best LED Grow Lights Info.11 June 2017.Archivedfrom the original on 30 July 2018.Retrieved24 June2017.

[104] Scott, K.J.; Wills, R.R.H.; Patterson, B.D. (1971). "Removal by ultra-violet lamp of ethylene and other hydrocarbons produced by bananas".Journal of the Science of Food and Agriculture.22(9): 496–7.Bibcode:1971JSFA...22..496S.doi:10.1002/jsfa.2740220916.

[105] Scott, KJ; Wills, RBH (1973). "Atmospheric pollutants destroyed in an ultra violet scrubber".Laboratory Practice.22(2): 103–6.PMID 4688707.

[106] Shorter, AJ; Scott, KJ (1986). "Removal of ethylene from air and low oxygen atmospheres with ultra violet radiation".Lebensm-Wiss U Technology.19:176–9.

[107] Chang, Kenneth (7 May 2020)."Scientists Consider Indoor Ultraviolet Light to Zap Coronavirus in the Air".The New York Times.Archivedfrom the original on 7 May 2020.Retrieved9 May2020.

[108] Welch, David; et al. (January 2018)."Far-UVC light: A new tool to control the spread of airborne-mediated microbial diseases".Scientific Reports.8(1): 2752.Bibcode:2018NatSR...8.2752W.doi:10.1038/s41598-018-21058-w.ISSN 2045-2322.PMC5807439.PMID 29426899.

[109] "Coming of Age UV-C LED Technology Update".wateronline.com.Archivedfrom the original on 20 April 2017.

[110] "Solar Water Disinfection".Sodis.ch. 2 April 2011. Archived fromthe originalon 31 August 2012.Retrieved8 November2011.

[111] "Video Demos".Archived fromthe originalon 19 December 2014.Retrieved27 November2014.

[112] Lorenzo-Leal, Ana C.; Tam, Wenxi; Kheyrandish, Ata; Mohseni, Madjid; Bach, Horacio (31 October 2023). Barbosa, Joana (ed.)."Antimicrobial Activity of Filtered Far-UVC Light (222 nm) against Different Pathogens".BioMed Research International.2023:1–8.doi:10.1155/2023/2085140.ISSN 2314-6141.PMC10630020.PMID 37942030.

[113] Devitt, George; Johnson, Peter B.; Hanrahan, Niall; Lane, Simon I. R.; Vidale, Magdalena C.; Sheth, Bhavwanti; Allen, Joel D.; Humbert, Maria V.; Spalluto, Cosma M.; Hervé, Rodolphe C.; Staples, Karl; West, Jonathan J.; Forster, Robert; Divecha, Nullin; McCormick, Christopher J.; Crispin, Max; Hempler, Nils; Malcolm, Graeme P. A.; Mahajan, Sumeet (2023)."Mechanisms of SARS-CoV-2 Inactivation Using UVC Laser Radiation".ACS Photonics.11(1): 42–52.doi:10.1021/acsphotonics.3c00828.PMC10797618.PMID 38249683.

[114] Silberglied, Robert E.; Taylor, Orley R. (1978). "Ultraviolet Reflection and Its Behavioral Role in the Courtship of the Sulfur Butterflies Colias eurytheme and C. philodice (Lepidoptera, Pieridae)".Behavioral Ecology and Sociobiology.3(3): 203–43.doi:10.1007/bf00296311.S2CID 38043008.

[Meyer-Rohow_&_Järvilehto_1997-115] Meyer-Rochow, V.B.; Järvilehto, M. (1997). "Ultraviolet colours in Pieris napi from northern and southern Finland: Arctic females are the brightest!".Naturwissenschaften.84(4): 165–168.Bibcode:1997NW.....84..165M.doi:10.1007/s001140050373.S2CID 46142866.

[116] "UVB Phototherapy".National Psoriasis Foundation, USA. Archived fromthe original(php)on 22 June 2007.Retrieved23 September2007.

[117] Diehl, J. J. E.; Baines, F. M.; Heijboer, A. C.; van Leeuwen, J. P.; Kik, M.; Hendriks, W. H.; Oonincx, D. G. A. B. (February 2018)."A comparison of UVb compact lamps in enabling cutaneous vitamin D synthesis in growing bearded dragons".Journal of Animal Physiology and Animal Nutrition.102(1): 308–316.doi:10.1111/jpn.12728.PMID 28452197.S2CID 30124686.

[118] "Vitamin D and Ultraviolet Light – a remarkable process".UV Guide UK.Archivedfrom the original on 31 May 2016.Retrieved13 January2017.

[119] Margulis, Lynn&Sagan, Dorion(1986).Origins of Sex: Three Billion Years of Genetic Recombination(book).1. Yale University Press.ISBN 978-0-300-04619-9.Archivedfrom the original on 29 May 2024.Retrieved22 November2020.

[1]

[2]

[3]

[4]

[5]

[6]

[7]

[8]

[9]

[10]

[11]

[12]

[13]

[14]

[15]

[16]

[17]

[18]

[19]

[20]

[21]

[22]

[23]

[24]

[25]

[26]

[27]

[28]

[29]

[30]

[31]

[32]

[33]

[34]

[35]

[36]

[37]

[38]

[39]

[40]

[41]

[42]

[43]

[44]

[45]

[46]

[47]

[48]

[49]

[50]

[51]

[52]

[53]

[54]

[55]

[56]

[57]

[58]

[59]

[60]

[61]

[62]

[63]

[64]

[65]

[66]

[67]

[68]

[69]

[70]

[71]

[72]

[73]

[74]

[75]

[76]

[77]

[78]

[79]

[80]

[81]

[82]

[83]

[84]

[85]

[86]

[87]

[88]

[89]

[90]

[91]

[92]

[93]

[94]

[95]

[96]

[97]

[98]

[99]

[100]

v t e Electromagnetic spectrum
Gamma rays X-rays Ultraviolet Visible Infrared Microwave Radio ←higherfrequencieslongerwavelengths→
Gamma rays	Very-high-energy gamma ray Ultra-high-energy gamma ray
X-rays	Soft X-ray Hard X-ray
Ultraviolet	Extreme ultraviolet Vacuum ultraviolet Lyman-alpha FUV MUV NUV UVC UVB UVA
Visible (optical)	Violet Blue Cyan Green Yellow Orange Red
Infrared	NIR(Bands:J,K,H) SWIR MWIR(Bands:L,M,N) LWIR FIR
Microwaves	W band V band Q band K_aband K band K_uband X band C band S band L band
Radio	THF EHF SHF UHF VHF HF MF LF VLF ULF SLF ELF
Wavelengthtypes	Microwave Shortwave Medium wave Longwave