Editing Ultraviolet (section)

== Blockers, absorbers, and windows ==
Ultraviolet absorbers are molecules used in organic materials ([[polymers]], [[paints]], etc.) to absorb UV radiation to reduce the [[UV degradation]] (photo-oxidation) of a material. The absorbers can themselves degrade over time, so monitoring of absorber levels in weathered materials is necessary.{{cn|date=May 2024}}

In [[sunscreen]], ingredients that absorb UVA/UVB rays, such as [[avobenzone]], [[oxybenzone]]<ref>{{cite journal |last1=Burnett |first1=M. E. |last2=Wang |first2=S. Q. |year=2011 |title=Current sunscreen controversies: a critical review |journal=Photodermatology, Photoimmunology & Photomedicine |volume=27 |issue=2| pages=58–67 |doi=10.1111/j.1600-0781.2011.00557.x |pmid=21392107| s2cid=29173997 |doi-access=}}</ref> and [[octyl methoxycinnamate]], are [[Organic compound|organic chemical absorbers]] or "blockers". They are contrasted with inorganic absorbers/"blockers" of UV radiation such as [[titanium dioxide]] and [[zinc oxide]].<ref>{{Cite journal |last=Dransfield |first=G.P. |date=2000-09-01 |title=Inorganic Sunscreens |url=https://academic.oup.com/rpd/article-abstract/91/1-3/271/1727863?redirectedFrom=fulltext |journal=Radiation Protection Dosimetry |volume=91 |issue=1–3 |pages=271–273 |doi=10.1093/oxfordjournals.rpd.a033216 |issn=0144-8420|url-access=subscription }}</ref>

For clothing, the [[Sun protective clothing|ultraviolet protection factor]] (UPF) represents the ratio of [[sunburn]]-causing UV without and with the protection of the fabric, similar to [[sun protection factor]] (SPF) ratings for [[sunscreen]].{{citation needed|date=July 2020}} Standard summer fabrics have UPFs around 6, which means that about 20% of UV will pass through.{{citation needed|date=July 2020}}

Suspended [[nanoparticle]]s in stained-glass prevent UV rays from causing chemical reactions that change image colors.{{citation needed|date=June 2020}} A set of stained-glass color-reference chips is planned to be used to calibrate the color cameras for the 2019 [[ESA]] Mars rover mission, since they will remain unfaded by the high level of UV present at the surface of Mars.{{citation needed|date=May 2020}}

Common [[soda–lime glass]], such as window glass, is partially [[transparency and translucency|transparent]] to UVA, but is [[opaque]] to shorter wavelengths, passing about 90% of the light above 350&nbsp;nm, but blocking over 90% of the light below 300&nbsp;nm.<ref>{{cite web | title = Soda Lime Glass Transmission Curve | url = http://www.sinclairmfg.com/datasheets/optical3.html | url-status=dead | archive-url = https://web.archive.org/web/20120327213950/http://www.sinclairmfg.com/datasheets/optical3.html | archive-date = 27 March 2012 | access-date = 20 January 2012 }}</ref><ref>{{cite web|url=http://www.pgo-online.com/intl/katalog/curves/B270_kurve.html|title=B270-Superwite Glass Transmission Curve|website=Präzisions Glas & Optik|access-date=2017-01-13|url-status=live|archive-url=https://web.archive.org/web/20170709022735/https://www.pgo-online.com/intl/katalog/curves/B270_kurve.html|archive-date=9 July 2017}}</ref><ref>{{cite web|url=http://www.pgo-online.com/intl/katalog/curves/whitefl_kurve.html|title=Selected Float Glass Transmission Curve|website=Präzisions Glas & Optik|access-date=2017-01-13|url-status=live|archive-url=https://web.archive.org/web/20151019025929/http://www.pgo-online.com/intl/katalog/curves/whitefl_kurve.html|archive-date=19 October 2015}}</ref> A study found that car windows allow 3–4% of ambient UV to pass through, especially if the UV was greater than 380&nbsp;nm.<ref name="UV exposure in cars">{{cite journal |last1=Moehrle |first1=Matthias |last2=Soballa |first2=Martin |last3=Korn |first3=Manfred |title=UV exposure in cars |journal=Photodermatology, Photoimmunology & Photomedicine |date=2003 |volume=19 |issue=4 |pages=175–181 |doi=10.1034/j.1600-0781.2003.00031.x |pmid=12925188 |s2cid=37208948 |language=en |issn=1600-0781}}</ref> Other types of car windows can reduce transmission of UV that is greater than 335&nbsp;nm.<ref name="UV exposure in cars" /> [[Fused quartz]], depending on quality, can be transparent even to [[#VUV|vacuum UV]] wavelengths. Crystalline [[quartz]] and some crystals such as CaF<sub>2</sub> and MgF<sub>2</sub> transmit well down to 150&nbsp;nm or 160&nbsp;nm wavelengths.<ref>{{cite web | url=https://www.newport.com/n/optical-materials | title=Optical Materials | publisher=Newport Corporation | access-date=14 June 2020 | archive-date=11 June 2020 | archive-url=https://web.archive.org/web/20200611014515/https://www.newport.com/n/optical-materials | url-status=live }}</ref>

[[Wood's glass]] is a deep violet-blue barium-sodium silicate glass with about 9% [[nickel(II) oxide]] developed during [[World War I]] to block visible light for covert communications. It allows both infrared daylight and ultraviolet night-time communications by being transparent between 320&nbsp;nm and 400&nbsp;nm and also the longer infrared and just-barely-visible red wavelengths. Its maximum UV transmission is at 365&nbsp;nm, one of the wavelengths of [[mercury lamp]]s.{{cn|date=May 2024}}