Editing Oxygen (section)

==Applications==
{{see also|Breathing gas|Redox|Combustion}}

===Medical===
[[File:Home oxygen concentrator.jpg|thumb|upright|left|An [[oxygen concentrator]] in an [[emphysema]] patient's house|alt=A gray device with a label DeVILBISS LT4000 and some text on the front panel. A green plastic pipe is running from the device.]]

{{Main|Oxygen therapy}}

Uptake of {{chem|O|2}} from the air is the essential purpose of [[Respiration (physiology)|respiration]], so oxygen supplementation is used in [[medicine]]. Treatment not only increases oxygen levels in the patient's blood, but has the secondary effect of decreasing resistance to blood flow in many types of diseased lungs, easing work load on the heart. [[Oxygen therapy]] is used to treat [[emphysema]], [[pneumonia]], some heart disorders ([[congestive heart failure]]), some disorders that cause increased [[pulmonary artery pressure]], and any [[disease]] that impairs the body's ability to take up and use gaseous oxygen.<ref name="ECE510">[[#Reference-idCook1968|Cook & Lauer 1968]], p. 510</ref>

Treatments are flexible enough to be used in hospitals, the patient's home, or increasingly by portable devices. [[Oxygen tent]]s were once commonly used in oxygen supplementation, but have since been replaced mostly by the use of [[oxygen mask]]s or [[nasal cannula]]s.<ref name="pmid18540928">{{cite journal |author=Sim MA |display-authors=4 |author2=Dean P |author3=Kinsella J |author4= Black R |author5=Carter R|author6=Hughes M |title=Performance of oxygen delivery devices when the breathing pattern of respiratory failure is simulated |journal=Anaesthesia |volume=63 |issue=9 |pages=938–40 |date=2008 |pmid=18540928 |doi=10.1111/j.1365-2044.2008.05536.x|s2cid=205248111 |doi-access=free }}</ref>

[[Hyperbaric medicine|Hyperbaric]] (high-pressure) medicine uses special [[hyperbaric oxygen chamber|oxygen chambers]] to increase the [[partial pressure]] of {{chem|O|2}} around the patient and, when needed, the medical staff.<ref name="pmid8931286">{{cite journal |author=Stephenson RN |author2=Mackenzie I |author3=Watt SJ |author4=Ross JA |title=Measurement of oxygen concentration in delivery systems used for hyperbaric oxygen therapy |journal=Undersea Hyperb Med |volume=23 |issue=3 |pages=185–88 |date=1996 |pmid=8931286 |url=http://archive.rubicon-foundation.org/2245 |access-date=September 22, 2008 |archive-date=August 11, 2011 |archive-url=https://web.archive.org/web/20110811175247/http://archive.rubicon-foundation.org/2245 |url-status=usurped }}</ref> [[Carbon monoxide poisoning]], [[gas gangrene]], and [[decompression sickness]] (the 'bends') are sometimes addressed with this therapy.<ref>{{cite web|url=http://www.uhms.org/Default.aspx?tabid=270 |title=Indications for hyperbaric oxygen therapy |author=Undersea and Hyperbaric Medical Society |access-date=September 22, 2008 |author-link=Undersea and Hyperbaric Medical Society |url-status=dead |archive-url=https://web.archive.org/web/20080912184905/http://www.uhms.org/Default.aspx?tabid=270 |archive-date=September 12, 2008 }}</ref> Increased {{chem|O|2}} concentration in the lungs helps to displace [[carbon monoxide]] from the heme group of [[hemoglobin]].<ref>{{cite web |url=http://www.uhms.org/ResourceLibrary/Indications/CarbonMonoxidePoisoning/tabid/272/Default.aspx |title=Carbon Monoxide |author=Undersea and Hyperbaric Medical Society |access-date=September 22, 2008 |archive-url=https://web.archive.org/web/20080725005744/http://www.uhms.org/ResourceLibrary/Indications/CarbonMonoxidePoisoning/tabid/272/Default.aspx <!--Added by H3llBot--> |archive-date=July 25, 2008}}</ref><ref name="pmid15233173">{{cite journal |author=Piantadosi CA |title=Carbon monoxide poisoning |journal=Undersea Hyperb Med |volume=31 |issue=1 |pages=167–77 |date=2004 |pmid=15233173 |url=http://archive.rubicon-foundation.org/4002 |access-date=September 22, 2008 |archive-date=February 3, 2011 |archive-url=https://web.archive.org/web/20110203090807/http://archive.rubicon-foundation.org/4002 |url-status=usurped }}</ref> Oxygen gas is poisonous to the [[anaerobic bacteria]] that cause gas gangrene, so increasing its partial pressure helps kill them.<ref>{{cite journal |author=Hart GB |author2=Strauss MB |title=Gas Gangrene&nbsp;– Clostridial Myonecrosis: A Review |journal=J. Hyperbaric Med |volume=5 |issue=2 |pages=125–44 |date=1990 |url=http://archive.rubicon-foundation.org/4428 |access-date=September 22, 2008 |archive-date=February 3, 2011 |archive-url=https://web.archive.org/web/20110203090838/http://archive.rubicon-foundation.org/4428 |url-status=usurped }}</ref><ref>{{cite journal |author=Zamboni WA |author2=Riseman JA |author3=Kucan JO |title=Management of Fournier's Gangrene and the role of Hyperbaric Oxygen |journal=J. Hyperbaric Med |volume=5 |issue=3 |pages=177–86 |date=1990 |url=http://archive.rubicon-foundation.org/4431 |access-date=September 22, 2008 |archive-date=February 3, 2011 |archive-url=https://web.archive.org/web/20110203090958/http://archive.rubicon-foundation.org/4431 |url-status=usurped }}</ref> Decompression sickness occurs in divers who decompress too quickly after a dive, resulting in bubbles of inert gas, mostly nitrogen and helium, forming in the blood. Increasing the pressure of {{chem|O|2}} as soon as possible helps to redissolve the bubbles back into the blood so that these excess gasses can be exhaled naturally through the lungs.<ref name="ECE510" /><ref>{{cite web |url=http://www.uhms.org/ResourceLibrary/Indications/DecompressionSickness/tabid/275/Default.aspx |title=Decompression Sickness or Illness and Arterial Gas Embolism |author=Undersea and Hyperbaric Medical Society |access-date=September 22, 2008 |archive-url=https://web.archive.org/web/20080705210353/http://www.uhms.org/ResourceLibrary/Indications/DecompressionSickness/tabid/275/Default.aspx <!--Added by H3llBot--> |archive-date=July 5, 2008}}</ref><ref>{{cite journal |last=Acott |first=C. |title=A brief history of diving and decompression illness |journal=South Pacific Underwater Medicine Society Journal |volume=29 |issue=2 |date=1999 |url=http://archive.rubicon-foundation.org/6004 |access-date=September 22, 2008 |archive-date=September 5, 2011 |archive-url=https://web.archive.org/web/20110905152645/http://archive.rubicon-foundation.org/6004 |url-status=usurped }}</ref> Normobaric oxygen administration at the highest available concentration is frequently used as first aid for any diving injury that may involve inert gas bubble formation in the tissues. There is epidemiological support for its use from a statistical study of cases recorded in a long term database.<ref name="Longphre et al 2007">{{cite journal|title=First aid normobaric oxygen for the treatment of recreational diving injuries |last1=Longphre |first1=JM |last2=Denoble |first2=PJ |last3=Moon |first3=RE |last4=Vann |first4=RD |last5=Freiberger |first5=JJ |journal=Undersea & Hyperbaric Medicine |date=2007 |volume=34 |issue=1 |pages=43–49|url=https://pdfs.semanticscholar.org/3c96/eec9b2ae3f25ffc0569f26b7329d5b05e213.pdf |archive-url=https://web.archive.org/web/20181001104203/https://pdfs.semanticscholar.org/3c96/eec9b2ae3f25ffc0569f26b7329d5b05e213.pdf |url-status=dead |archive-date=2018-10-01 |via=Rubicon Research Repository |pmid=17393938 |s2cid=3236557 }}</ref><ref name="Emergency O2 for scuba">{{cite web |url=https://www.diversalertnetwork.org/training/courses/course_eo2 |title=Emergency Oxygen for Scuba Diving Injuries |publisher=Divers Alert Network |author=<!--not specified--> |access-date=October 1, 2018 |archive-date=April 20, 2020 |archive-url=https://web.archive.org/web/20200420114653/https://www.diversalertnetwork.org/training/courses/course_eo2 |url-status=live }}</ref><ref name="DAN Europe">{{cite web |url=https://daneurope.org/web/guest/readarticle;jsessionid=F8EB8916CD93E6A793F9F875BF5FC782?p_p_id=web_content_reading&p_p_lifecycle=0&p_p_mode=view&p_r_p_-1523133153_groupId=10103&p_r_p_-1523133153_articleId=11601&p_r_p_-1523133153_articleVersion=1.0&p_r_p_-1523133153_commaCategories=&p_r_p_-1523133153_commaTags= |title=Oxygen First Aid for Scuba Diving Injuries |publisher=Divers Alert Network Europe |author=<!--not specified--> |access-date=October 1, 2018 |archive-date=June 10, 2020 |archive-url=https://web.archive.org/web/20200610202203/https://daneurope.org/web/guest/readarticle;jsessionid=F8EB8916CD93E6A793F9F875BF5FC782?p_p_id=web_content_reading&p_p_lifecycle=0&p_p_mode=view&p_r_p_-1523133153_groupId=10103&p_r_p_-1523133153_articleId=11601&p_r_p_-1523133153_articleVersion=1.0&p_r_p_-1523133153_commaCategories=&p_r_p_-1523133153_commaTags= |url-status=live }}</ref>
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===Life support and recreational use===
[[File:STS057-89-067 - Wisoff on the Arm (Retouched).jpg|thumb|Low-pressure pure {{chem|O|2}} is used in [[space suit]]s.]]

An application of {{chem|O|2}} as a low-pressure [[breathing gas]] is in modern [[space suit]]s, which surround their occupant's body with the breathing gas. These devices use nearly pure oxygen at about one-third normal pressure, resulting in a normal blood partial pressure of {{chem|O|2}}. This trade-off of higher oxygen concentration for lower pressure is needed to maintain suit flexibility.<ref name="pmid11541018">{{cite journal|author=Morgenthaler GW|author2=Fester DA|author3=Cooley CG| title=As assessment of habitat pressure, oxygen fraction, and EVA suit design for space operations|journal=Acta Astronautica |volume= 32|issue=1|pages=39–49|date=1994|pmid=11541018|doi=10.1016/0094-5765(94)90146-5|bibcode = 1994AcAau..32...39M }}</ref><ref name="pmid2730484">{{cite journal|author=Webb JT|author2= Olson RM|author3=Krutz RW|author4=Dixon G|author5=Barnicott PT|title=Human tolerance to 100% oxygen at 9.5 psia during five daily simulated 8-hour EVA exposures|journal=Aviat Space Environ Med|volume=60|issue=5|pages=415–21|date=1989|pmid=2730484|doi=10.4271/881071}}</ref>

[[Scuba diving|Scuba]] and [[Surface-supplied diving|surface-supplied]] [[underwater diving|underwater diver]]s and [[submarine]]s also rely on artificially delivered {{chem|O|2}}. Submarines, submersibles and [[atmospheric diving suits]] usually operate at normal atmospheric pressure. Breathing air is scrubbed of carbon dioxide by chemical extraction and oxygen is replaced to maintain a constant partial pressure. [[Ambient pressure]] divers breathe air or gas mixtures with an oxygen fraction suited to the operating depth. Pure or nearly pure {{chem|O|2}} use in diving at pressures higher than atmospheric is usually limited to [[rebreathers]], or [[Decompression (diving)|decompression]] at relatively shallow depths (~6 meters depth, or less),<ref name="Acott">{{cite journal|last=Acott|first=C.|title=Oxygen toxicity: A brief history of oxygen in diving|journal=South Pacific Underwater Medicine Society Journal|volume=29|issue=3|date=1999|url=http://archive.rubicon-foundation.org/6014|access-date=September 21, 2008|archive-date=December 25, 2010|archive-url=https://web.archive.org/web/20101225073221/http://archive.rubicon-foundation.org/6014|url-status=usurped}}</ref><ref name="Longphre">{{cite journal|last1=Longphre|first1=J. M.|title=First aid normobaric oxygen for the treatment of recreational diving injuries|journal=Undersea Hyperb. Med.|volume=34|issue=1|pages=43–49|date=2007|pmid=17393938|url=http://archive.rubicon-foundation.org/5514|access-date=September 21, 2008|display-authors=4|last2=Denoble|first2=P. J.|last3=Moon|first3=R. E.|last4=Vann|first4=R. D.|last5=Freiberger|first5=J. J.|archive-url=https://web.archive.org/web/20080613163501/http://archive.rubicon-foundation.org/5514|archive-date=June 13, 2008|url-status=usurped}}</ref> or [[Hyperbaric treatment schedules|medical treatment in recompression chambers]] at pressures up to 2.8 bar, where acute oxygen toxicity can be managed without the risk of drowning. Deeper diving requires significant dilution of {{chem|O|2}} with other gases, such as nitrogen or helium, to prevent [[oxygen toxicity]].<ref name="Acott" />

People who climb mountains or fly in non-pressurized [[fixed-wing aircraft]] sometimes have supplemental {{chem|O|2}} supplies.<ref group=lower-alpha>The reason is that increasing the proportion of oxygen in the breathing gas at low pressure acts to augment the inspired {{chem|O|2}} partial pressure nearer to that found at sea-level.</ref> Pressurized commercial airplanes have an emergency supply of {{chem|O|2}} automatically supplied to the passengers in case of cabin depressurization. Sudden cabin pressure loss activates [[chemical oxygen generator]]s above each seat, causing [[oxygen mask]]s to drop. Pulling on the masks "to start the flow of oxygen" as cabin safety instructions dictate, forces iron filings into the [[sodium chlorate]] inside the canister.<ref name="NBB301" /> A steady stream of oxygen gas is then produced by the [[exothermic]] reaction.<ref>{{Greenwood&Earnshaw2nd}}</ref>

Oxygen, as a mild [[euphoria|euphoric]], has a history of recreational use in [[oxygen bar]]s and in [[sport]]s. Oxygen bars are establishments found in the United States since the late 1990s that offer higher than normal {{chem|O|2}} exposure for a minimal fee.<ref name="FDA-O2Bars">{{cite journal|url=https://www.fda.gov/Fdac/features/2002/602_air.html| title=Oxygen Bars: Is a Breath of Fresh Air Worth It?|last=Bren|first=Linda|journal=FDA Consumer Magazine| volume=36| issue=6| pages=9–11|publisher=U.S. Food and Drug Administration|date=November–December 2002|access-date=December 23, 2007|archive-url=https://web.archive.org/web/20071018041754/https://www.fda.gov/Fdac/features/2002/602_air.html|archive-date=October 18, 2007|url-status=dead| pmid=12523293}}</ref> Professional athletes, especially in [[American football]], sometimes go off-field between plays to don oxygen masks to boost performance. The pharmacological effect is doubted; a [[placebo]] effect is a more likely explanation.<ref name="FDA-O2Bars" /> Available studies support a performance boost from oxygen enriched mixtures only if it is inhaled ''during'' [[aerobic exercise]].<ref>{{cite web|url=http://www.pponline.co.uk/encyc/1008.htm|title= Ergogenic Aids|access-date=January 4, 2008|publisher=Peak Performance Online |archive-url = https://web.archive.org/web/20070928051412/http://www.pponline.co.uk/encyc/1008.htm <!--Added by H3llBot--> |archive-date = September 28, 2007}}</ref>

Other recreational uses that do not involve breathing include [[pyrotechnic]] applications, such as [[George Goble]]'s five-second ignition of [[barbecue]] grills.<ref>{{cite web|url=http://www.bkinzel.de/misc/ghg/index.html|title=George Goble's extended home page (mirror)|access-date=March 14, 2008|archive-url=https://web.archive.org/web/20090211213613/http://www.bkinzel.de/misc/ghg/index.html|archive-date=February 11, 2009|url-status=dead}}</ref><!-- - Primary source; many secondary sources exist but they only provide less information and more ads - -->

===Industrial===
[[File:Clabecq JPG01.jpg|thumb|Most commercially produced {{chem|O|2}} is used to [[smelting|smelt]] and/or [[Decarburization|decarburize]] [[iron]].|alt=An elderly worker in a helmet is facing his side to the viewer in an industrial hall. The hall is dark but is illuminated yellow glowing splashes of a melted substance.]]

[[Smelting]] of [[iron ore]] into [[steel]] consumes 55% of commercially produced oxygen.<ref name="NBB301" /> In this process, {{chem|O|2}} is injected through a high-pressure lance into molten iron, which removes [[sulfur]] impurities and excess [[carbon]] as the respective oxides, {{chem|SO|2}} and {{chem|CO|2}}. The reactions are [[exothermic reaction|exothermic]], so the temperature increases to 1,700&nbsp;°[[Celsius|C]].<ref name="NBB301" />

Another 25% of commercially produced oxygen is used by the chemical industry.<ref name="NBB301" /> [[Ethylene]] is reacted with {{chem|O|2}} to create [[ethylene oxide]], which, in turn, is converted into [[ethylene glycol]]; the primary feeder material used to manufacture a host of products, including [[antifreeze]] and [[polyester]] polymers (the precursors of many [[plastic]]s and [[fabric]]s).<ref name="NBB301" />

Most of the remaining 20% of commercially produced oxygen is used in medical applications, [[gas welding|metal cutting and welding]], as an oxidizer in [[rocket fuel]], and in [[water treatment]].<ref name="NBB301" /> Oxygen is used in [[oxyacetylene welding]], burning [[acetylene]] with {{chem|O|2}} to produce a very hot flame. In this process, metal up to {{convert|60|cm|abbr=on}} thick is first heated with a small oxy-acetylene flame and then quickly cut by a large stream of {{chem|O|2}}.<ref name="ECE508">[[#Reference-idCook1968|Cook & Lauer 1968]], p. 508</ref>