Editing Nitrous oxide (section)

==Uses==

===Rocket motors===
Nitrous oxide may be used as an [[oxidizing agent|oxidiser]] in a [[rocket]] motor. Compared to other oxidisers, it is much less toxic and more stable at room temperature, making it easier to store and safer to carry on a flight. Its high density and low storage pressure (when maintained at low temperatures) make it highly competitive with stored high-pressure gas systems.<ref>{{cite web|author=Berger, Bruno |date=5 October 2007 |url=http://www.spl.ch/publication/SPL_Papers/N2O_safety_e.pdf |archive-url=https://ghostarchive.org/archive/20221009/http://www.spl.ch/publication/SPL_Papers/N2O_safety_e.pdf |archive-date=2022-10-09 |url-status=live |title=Is nitrous oxide safe? |publisher=Swiss Propulsion Laboratory |pages=1–2 |quote=...Self pressurizing (Vapor pressure at 20°C is ~50.1 bar...Nontoxic, low reactivity -> rel. safe handling (General safe ???)...Additional energy from decomposition (as a monopropellant: ISP of 170 s)...Specific impulse doesn't change much with O/F...[page 2] N{{ssub|2}}O is a monopropellant (as H{{ssub|2}}O{{ssub|2}} or Hydrazine...)}}</ref>

In a 1914 patent, American rocket pioneer [[Robert Goddard]] suggested nitrous oxide and gasoline as possible propellants for a liquid-fuelled rocket.<ref>Goddard, R. H. (1914) "Rocket apparatus" {{US patent|1103503}}</ref> Nitrous oxide has been the oxidiser of choice in several [[hybrid rocket]] designs (using [[solid fuel]] with a liquid or gaseous oxidiser). The combination of nitrous oxide with [[hydroxyl-terminated polybutadiene]] fuel has been used by [[SpaceShipOne]] and others. It also is notably used in [[amateur rocketry|amateur]] and [[high power rocket]]ry with various plastics as the fuel.

Nitrous oxide may also be used as a [[monopropellant rocket|monopropellant]]. In the presence of a heated [[catalyst]] at a temperature of {{convert|577|C}}, {{chem|N|2|O}} decomposes exothermically into nitrogen and oxygen.<ref>[http://spg-corp.com/nitrous-oxide-safety.html Nitrous Oxide Safety]. Space Propulsion Group (2012)</ref> Because of the large heat release, the catalytic action rapidly becomes secondary, as thermal [[Chain reaction|autodecomposition]] becomes dominant. In a vacuum thruster, this may provide a monopropellant [[specific impulse]] (''I''{{ssub|sp}}) up to 180 s. While noticeably less than the ''I''{{ssub|sp}} available from [[hydrazine]] thrusters (monopropellant, or [[Bipropellant rocket|bipropellant]] with [[dinitrogen tetroxide]]), the decreased toxicity makes nitrous oxide a worthwhile option.

The ignition of nitrous oxide depends critically on pressure. It [[deflagration|deflagrates]] at approximately {{convert|600|C}} at a pressure of 309&nbsp;psi (21&nbsp;atmospheres).<ref name="Munke">Munke, Konrad (2 July 2001) [http://hobbyspace.com/AAdmin/archive/SpecialTopics/Misc/eindhoven.pdf Nitrous Oxide Trailer Rupture], Report at CGA Seminar "Safety and Reliability of Industrial Gases, Equipment and Facilities", 15–17 October 2001, St. Louis, Missouri</ref> At 600&nbsp;{{abbr|psi|pounds per square inch}}, the required ignition energy is only 6&nbsp;joules, whereas at 130&nbsp;psi a 2,500-joule ignition energy input is insufficient.<ref>{{cite web|url=http://www.scaled.com/images/uploads/news/N2OSafetyGuidelines.pdf |title=Scaled Composites Safety Guidelines for {{chem|N|2|O}} |publisher=Scaled Composites |date=17 June 2009 |archive-url=https://web.archive.org/web/20110712044612/http://www.scaled.com/images/uploads/news/N2OSafetyGuidelines.pdf |access-date=29 December 2013 |archive-date=12 July 2011 |quote=For example, N2O flowing at 130 psi in an epoxy composite pipe would not react even with a 2500 J ignition energy input. At 600 psi, however, the required ignition energy was only 6 J.}}</ref><ref>[http://hobbyspace.com/AAdmin/archive/SpecialTopics/Misc/pratt-explosion.pdf FR-5904]. Pratt & Whitney Aircraft.</ref>

===Internal combustion engine===
{{Main|Nitrous oxide engine}}

In vehicle [[racing]], nitrous oxide (often called "[[Nitrous oxide engine|nitrous]]") increases [[engine power]] by providing more oxygen during combustion, thus allowing the engine to burn more fuel. It is an oxidising agent roughly equivalent to hydrogen peroxide, and much stronger than molecular oxygen. Nitrous oxide is not flammable at low pressure/temperature, but at about {{convert|300|C}}, its breakdown delivers more oxygen than atmospheric air. It often is mixed with another fuel that is easier to deflagrate. 

Nitrous oxide is stored as a compressed liquid. In an engine [[Inlet manifold|intake manifold]], the [[heat of vaporization|evaporation]] and expansion of the liquid causes a large drop in intake charge temperature, resulting in a denser charge and allowing more air/fuel mixture to enter the cylinder. Sometimes nitrous oxide is injected into (or prior to) the intake manifold, whereas other systems directly inject it just before the cylinder (direct port injection).

The technique was used during [[World War II]] by [[Luftwaffe]] aircraft with the [[GM-1]] system to boost the power output of [[aircraft engine]]s. Originally meant to provide the Luftwaffe standard aircraft with superior high-altitude performance, technological considerations limited its use to extremely high altitudes. Accordingly, it was only used by specialised planes such as high-altitude [[reconnaissance aircraft]], [[schnellbomber|high-speed bombers]] and high-altitude [[interceptor aircraft]]. It sometimes could be found on Luftwaffe aircraft also fitted with another engine-boost system, [[MW 50]], a form of [[Water injection (engine)|water injection]] for aviation engines that used [[methanol]] for its boost capabilities.

One of the major problems of nitrous oxide oxidant in a reciprocating engine is excessive power: if the mechanical structure of the engine is not properly reinforced, it may be severely damaged or destroyed. It is important with nitrous oxide augmentation of [[petrol engine]]s to maintain proper and evenly spread [[operating temperature]]s and fuel levels to prevent [[pre-ignition]] (also called detonation or spark knock).<ref>Cline, Allen W. (January 2000) [http://www.contactmagazine.com/Issue54/EngineBasics.html "Engine Basics: Detonation and Pre-Ignition"]. ''CONTACT!'' Magazine</ref> However, most problems associated with nitrous oxide come not from excessive power but from excessive pressure, since the gas builds up a much denser charge in the cylinder. The increased pressure and temperature can melt, crack, or warp the piston, valve, and cylinder head.

Automotive-grade liquid nitrous oxide differs slightly from medical-grade. A small amount of [[sulfur dioxide]] ({{chem|SO|2}}) is added to prevent substance abuse.<ref name="Automotive gas">{{cite web|url=https://www.holley.com/support/faq/?category=NOS |work=Holley |title=Holley performance products, FAQ for Nitrous Oxide Systems |access-date=18 December 2013}}</ref>

===Aerosol propellant for food===
[[File:N2O whippets.jpg|thumb|right|Food-grade {{chem|N|2|O}} [[whipped-cream charger]]s]]
The gas is approved for use as a [[food additive]] ([[E number|E&nbsp;number]]: E942), specifically as an [[Aerosol spray#Aerosol propellants|aerosol spray propellant]]. It is commonly used in aerosol [[whipped cream]] canisters and [[cooking spray]]s.

The gas is extremely soluble in fatty compounds. In pressurised aerosol whipped cream, it is dissolved in the fatty cream until it leaves the can, when it becomes gaseous and thus creates foam. This produces whipped cream four times the volume of the liquid, whereas whipping air into cream only produces twice the volume. Unlike air, nitrous oxide inhibits [[rancidification]] of the butterfat. Carbon dioxide cannot be used for whipped cream because it is acidic in water, which would curdle the cream and give it a seltzer-like "sparkle".

Extra-frothed whipped cream produced with nitrous oxide is unstable, and will return to liquid within half an hour to one hour.<ref>{{Cite web|url=http://www.explora-science.net/nitrousoxide-use-as-a-propellant-and-in-cooking/|title=Explora Science {{!}} Nitrous use as a propellant and in cooking|language=en-US|access-date=2019-02-19|archive-date=27 February 2019|archive-url=https://web.archive.org/web/20190227015310/http://www.explora-science.net/nitrousoxide-use-as-a-propellant-and-in-cooking/}}</ref> Thus, it is not suitable for decorating food that will not be served immediately.

In December 2016, there was a shortage of aerosol whipped cream in the United States, with canned whipped cream use at its peak during the [[Christmas and holiday season]], due to an explosion at the [[Air Liquide]] nitrous oxide facility in [[Florida]] in late August. The company prioritized the remaining supply of nitrous oxide to medical customers rather than to food manufacturing.<ref>{{cite news |last=Dewey |first=Caitlin |url=https://www.washingtonpost.com/news/wonk/wp/2016/12/21/the-real-reason-you-cant-buy-whipped-cream-this-christmas/ |title=The real reason grocery stores are running out of whipped cream this Christmas |newspaper=[[The Washington Post]] |date=2016-12-21 |access-date=2016-12-22 }}</ref>

Also, cooking spray, made from various oils with [[lecithin]] [[emulsifier]], may use nitrous oxide [[propellant]], or alternatively food-grade [[ethanol|alcohol]] or [[propane]].

===Medical===
{{Main|Nitrous oxide (medication)}}
[[File:N2O Medical Tanks.jpg|thumb|right|upright|Medical-grade {{chem|N|2|O}} tanks used in [[dentistry]]]]

Nitrous oxide has been used in dentistry and surgery, as an anaesthetic and analgesic, since 1844.<ref name="Drug discovery">{{cite book|url=https://books.google.com/books?id=mYQxRY9umjcC |author=Sneader W |title=Drug Discovery –A History |chapter=Systematic Medicine |pages=74–87 |date=2005 |publisher=John Wiley and Sons |isbn=978-0-471-89980-8}}</ref> In the early days, the gas was administered through simple inhalers consisting of a breathing bag made of rubber cloth.<ref name="use in dentistry">{{cite journal|author=Miller AH |title=Technical Development of Gas Anesthesia |journal=Anesthesiology |volume=2 |issue=4 |pages=398–409 |year=1941 |doi=10.1097/00000542-194107000-00004|s2cid=71117361 |doi-access=free }}</ref> Today, the gas is administered in hospitals by means of an automated [[relative analgesia machine]], with an [[anaesthetic vaporiser]] and a [[medical ventilator]], that delivers a precisely dosed and breath-actuated flow of [[nitrous oxide and oxygen|nitrous oxide mixed with oxygen]] in a 2:1 ratio.

Nitrous oxide is a weak [[general anaesthetic]], and so is generally not used alone in general anaesthesia, but used as a carrier gas (mixed with oxygen) for more powerful general anaesthetic drugs such as [[sevoflurane]] or [[desflurane]]. It has a [[minimum alveolar concentration]] of 105% and a [[blood/gas partition coefficient]] of 0.46. The use of nitrous oxide in anaesthesia can increase the risk of postoperative nausea and vomiting.<ref>{{Cite journal|last1=Divatia|first1=Jigeeshu V.|last2=Vaidya|first2=Jayant S.|last3=Badwe|first3=Rajendra A.|last4=Hawaldar|first4=Rohini W.|title=Omission of Nitrous Oxide during Anesthesia Reduces the Incidence of Postoperative Nausea and Vomiting|journal=Anesthesiology|volume=85|issue=5|pages=1055–1062|doi=10.1097/00000542-199611000-00014|pmid=8916823|year=1996|s2cid=41549796|doi-access=free}}</ref><ref>{{Cite journal|last=Hartung|first=John|title=Twenty-Four of Twenty-Seven Studies Show a Greater Incidence of Emesis Associated with Nitrous Oxide than with Alternative Anesthetics|journal=Anesthesia & Analgesia|volume=83|issue=1|pages=114–116|doi=10.1213/00000539-199607000-00020|year=1996}}</ref><ref>{{Cite journal|last1=Tramèr|first1=M.|last2=Moore|first2=A.|last3=McQuay|first3=H.|date=February 1996|title=Omitting nitrous oxide in general anaesthesia: meta-analysis of intraoperative awareness and postoperative emesis in randomized controlled trials|journal=British Journal of Anaesthesia|volume=76|issue=2|pages=186–193|pmid=8777095|doi=10.1093/bja/76.2.186|doi-access=free}}</ref>

Dentists use a simpler machine which only delivers an {{chem|N|2|O}}/{{chem|O|2}} mixture for the patient to inhale while conscious but must still be a recognised purpose designed dedicated relative analgesic flowmeter with a minimum 30% of oxygen at all times and a maximum upper limit of 70% nitrous oxide. The patient is kept conscious throughout the procedure, and retains adequate mental faculties to respond to questions and instructions from the dentist.<ref>{{Cite journal|last=Council on Clinical Affairs|date=2013|title=Guideline on use of nitrous oxide for pediatric dental patients|url=http://www.aapd.org/media/policies_guidelines/g_nitrous.pdf |archive-url=https://ghostarchive.org/archive/20221009/http://www.aapd.org/media/policies_guidelines/g_nitrous.pdf |archive-date=2022-10-09 |url-status=live|journal=Reference Manual V37|volume=6|pages=206–210}}</ref>

Inhalation of nitrous oxide is used frequently to relieve pain associated with [[childbirth]], [[Physical trauma|trauma]], [[dentistry|oral surgery]] and [[acute coronary syndrome]] (including heart attacks). Its use during labour has been shown to be a safe and effective aid for birthing women.<ref>{{cite web |last=Copeland |first=Claudia |url=http://www.pregnancy.org/article/nitrous-oxide-analgesia-child-birth |title=Nitrous Oxide Analgesia for Childbirth |website=Pregnancy.org  |archive-url=https://web.archive.org/web/20110525080809/http://www.pregnancy.org/article/nitrous-oxide-analgesia-child-birth |archive-date=25 May 2011 }}</ref> Its use for acute coronary syndrome is of unknown benefit.<ref name="AHA10">{{cite journal|author=O'Connor RE |title=Part 10: acute coronary syndromes: 2010 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care |journal=Circulation |volume=122 |issue=18 Suppl 3 |pages=S787–817 |year=2010 |pmid=20956226 |doi=10.1161/CIRCULATIONAHA.110.971028 |author2=Brady W |author3=Brooks SC |last4=Diercks |first4=D. |last5=Egan |first5=J. |last6=Ghaemmaghami |first6=C. |last7=Menon |first7=V. |last8=O'Neil |first8=B. J. |last9=Travers |first9=A. H. |last10=Yannopoulos |doi-access=free }}</ref>

In Canada and the UK, [[Nitrous oxide (medication)|Entonox]] and Nitronox are used commonly by ambulance crews (including unregistered practitioners) as rapid and highly effective analgesic gas.

Fifty percent nitrous oxide can be considered for use by trained non-professional first aid responders in prehospital settings, given the relative ease and safety of administering 50% nitrous oxide as an analgesic. The rapid reversibility of its effect would also prevent it from precluding diagnosis.<ref>{{Cite journal|last1=Faddy|first1=S. C.|last2=Garlick|first2=S. R.|date=2005-12-01|title=A systematic review of the safety of analgesia with 50% nitrous oxide: can lay responders use analgesic gases in the prehospital setting?|journal=Emergency Medicine Journal|volume=22|issue=12|pages=901–908|doi=10.1136/emj.2004.020891|pmc=1726638|pmid=16299211}}</ref>

===Recreational===
{{main|Recreational use of nitrous oxide}}
[[File:Doctor and Mrs Syntax, with a party of friends, experimentin Wellcome L0022227.jpg|thumb|[[Aquatint]] depiction of a laughing gas party in the nineteenth century, by [[Thomas Rowlandson]]]]
[[File:Ban of Nitrous oxide use.jpg|thumb|Street sign indicating ban of nitrous oxide use near the Poelestraat in [[Groningen]]]]
[[File:Nitrous oxide whippits used recreationally as a drug by Dutch youngsters near a school, Utrecht, 2017 - 1.jpg|thumb|[[Whipped-cream charger|Whippit]] remnants (the small steel canisters) of recreational drug use, the Netherlands, 2017]]

[[recreational use of nitrous oxide|Recreational inhalation of nitrous oxide]], to induce [[euphoria (emotion)|euphoria]] and slight [[hallucination]]s, began with the British upper class in 1799 in gatherings known as "laughing gas parties".<ref>{{Cite book|last=Davy|first=Humphry|url=http://archive.org/details/researcheschemic00davy|title=Researches, chemical and philosophical: chiefly concerning nitrous oxide, or diphlogisticated nitrous air, and its respiration|date=1800|publisher=London : printed for J. Johnson, St. Paul's Church-Yard, by Biggs and Cottle, Bristol|others=Francis A. Countway Library of Medicine}}</ref>

From the 19th century, the widespread availability of the gas for medical and culinary purposes allowed for recreational use to greatly expand globally. In the UK as of 2014, nitrous oxide was estimated to be used by almost half a million young people at nightspots, festivals and parties.<ref>{{cite news | title = Warning over laughing gas misuse | url = https://www.theguardian.com/politics/2014/aug/09/warning-over-laughing-gas-misuse | date = 9 August 2014 | work = [[The Guardian]] |location=London |agency=[[Press Association]] | access-date = 9 August 2014}}</ref>

Widespread recreational use of the drug throughout the UK was featured in the 2017 [[Vice Media|Vice]] documentary ''Inside The Laughing Gas Black Market'', in which journalist [[Matt Shea (documentary filmmaker)|Matt Shea]] met with dealers of the drug who stole it from hospitals.<ref>{{Citation|last=VICE|title=Inside The Laughing Gas Black Market|date=2017-02-07|url=https://www.youtube.com/watch?v=gdhdAktIHtg| archive-url=https://ghostarchive.org/varchive/youtube/20211029/gdhdAktIHtg| archive-date=2021-10-29|access-date=2019-03-29}}{{cbignore}}</ref>

A significant issue cited in London's press is the effect of nitrous oxide canister littering, which is highly visible and causes significant complaints from communities.<ref>{{Cite web|url=https://metro.co.uk/2018/07/10/recycling-used-laughing-gas-canisters-for-cash-could-help-create-a-cleaner-britain-7694925/|title=Recycling used laughing gas canisters for cash could help create a cleaner Britain|date=2018-07-10|website=Metro|language=en-US|access-date=2019-07-15}}</ref>

Prior to 8 November 2023 in the UK, nitrous oxide was subject to the Psychoactive Substances Act 2016, making it illegal to produce, supply, import or export nitrous oxide for recreational use. The updated law prohibited possession of nitrous oxide, classifying it as a Class C drug under the Misuse of Drugs Act 1971.<ref>{{Cite web |title=Nitrous oxide ban: guidance |url=https://www.gov.uk/government/publications/nitrous-oxide-ban/nitrous-oxide-ban-guidance |access-date=2023-12-06 |website=GOV.UK |language=en}}</ref>

While nitrous oxide is understood by most recreational users to give a "safe high", many are unaware that excessive consumption may cause neurological harm which, if left untreated, can cause permanent neurological damage.<ref name="bbc.co.uk">{{cite news |title=Nitrous oxide: Laughing gas users risk spine damage, say doctors |url=https://www.bbc.co.uk/news/health-64718233 |access-date=26 March 2023}}</ref> In Australia, recreation use became a public health concern following a rise in reports of neurotoxicity and [[emergency room]] admissions. In the state of South Australia, legislation was passed in 2020 to restrict canister sales.<ref name=nangs/>

In 2024, under the street name "Galaxy Gas", nitrous oxide has exploded in popularity among young people for recreational use. Most of the popularity has been fostered through [[TikTok]].<ref>{{Cite web |last=Rakowitz |first=Rebecca |date=2024-09-27 |title=Everything Parents of Teens Need To Know about the Drug Going Viral on TikTok |url=https://www.sheknows.com/parenting/articles/3105253/galaxy-gas-everything-to-know/ |access-date=2024-09-30 |website=SheKnows |language=en-US}}</ref>