Editing Ozone (section)

==Ozone in Earth's atmosphere==
[[File:Atmospheric ozone.svg|thumb|upright=1.25|The distribution of atmospheric ozone in partial pressure as a function of altitude]]
[[File:Nimbus ozone Brewer-Dobson circulation.jpg|thumb|upright=1.25|Concentration of ozone as measured by the [[Nimbus program|Nimbus-7]] satellite]]
[[File:IM ozavg ept 200006.png|thumb|Total ozone concentration in June 2000 as measured by the NASA EP-TOMS satellite instrument]]
The standard way to express total ozone levels (the amount of ozone in a given vertical column) in the atmosphere is by using [[Dobson unit]]s. Point measurements are reported as [[mole fraction]]s in nmol/mol (parts per billion, ppb) or as [[concentration]]s in μg/m<sup>3</sup>. The study of ozone concentration in the atmosphere started in the 1920s.<ref>{{cite web |title=Measured Ozone Depletion |work=Ozone-Information.com |url=http://www.albany.edu/faculty/rgk/atm101/ozmeas.htm |access-date=2014-01-22 |archive-url=https://web.archive.org/web/20130914112129/http://www.albany.edu/faculty/rgk/atm101/ozmeas.htm |archive-date=2013-09-14}}</ref>

===Ozone layer===
{{Main|Ozone layer}}

====Location and production====
{{See also|Ozone–oxygen cycle|Ozone depletion}}

The highest levels of ozone in the atmosphere are in the [[stratosphere]], in a region also known as the [[ozone layer]] between about 10 and 50&nbsp;km above the surface (or between about 6 and 31 miles). However, even in this "layer", the ozone concentrations are only two to eight parts per million, so most of the oxygen there is dioxygen, O<sub>2</sub>, at about 210,000 parts per million by volume.<ref name="Hultman">{{cite book |last=Hultman |first=G. Eric |title=The Ozone Survival Manual |date=1980-01-01 |publisher=McGraw-Hill |isbn=978-0-915498-73-4}}</ref>

Ozone in the stratosphere is mostly produced from short-wave ultraviolet rays between 240 and 160&nbsp;nm. Oxygen starts to absorb weakly at 240&nbsp;nm in the Herzberg bands, but most of the oxygen is dissociated by absorption in the strong [[Schumann–Runge bands]] between 200 and 160&nbsp;nm where ozone does not absorb. While shorter wavelength light, extending to even the X-Ray limit, is energetic enough to dissociate molecular oxygen, there is relatively little of it, and, the strong solar emission at Lyman-alpha, 121&nbsp;nm, falls at a point where molecular oxygen absorption is a minimum.<ref>{{cite web |title=The MPI-Mainz UV/VIS Spectral Atlas of Gaseous Molecules of Atmospheric Interest: O2, Lyman-alpha |last=Keller-Rudek |first=Hannelore |url=http://joseba.mpch-mainz.mpg.de/spectral_atlas_data/cross_sections_plots/Oxygen/O2_Lyman%20alpha%20line_lin.jpg |archive-url=https://web.archive.org/web/20151117015120/http://joseba.mpch-mainz.mpg.de/spectral_atlas_data/cross_sections_plots/Oxygen/O2_Lyman%20alpha%20line_lin.jpg |archive-date=2015-11-17}}</ref>

The process of ozone creation and destruction is called the [[Chapman cycle]] and starts with the photolysis of molecular oxygen
: <chem>O2 -> [\ce{photon}] [(\ce{radiation}\ \lambda\ <\ 240\ \ce{nm})] 2O</chem>

followed by reaction of the oxygen atom with another molecule of oxygen to form ozone.
:<chem>O + O2 + M -> O3 + M</chem>

where "M" denotes the third body that carries off the excess energy of the reaction. The ozone molecule can then absorb a UV-C photon and dissociate
:<math chem>\ce{O3 -> O + O2} + \text{kinetic energy}</math>

The excess kinetic energy heats the stratosphere when the O atoms and the molecular oxygen fly apart and collide with other molecules. This conversion of UV light into kinetic energy warms the stratosphere. The oxygen atoms produced in the photolysis of ozone then react back with other oxygen molecule as in the previous step to form more ozone. In the clear atmosphere, with only nitrogen and oxygen, ozone can react with the atomic oxygen to form two molecules of {{chem2|O2}}:
:<chem>O3 + O -> 2 O2</chem>

An estimate of the rate of this termination step to the cycling of atomic oxygen back to ozone can be found simply by taking the ratios of the concentration of O<sub>2</sub> to O<sub>3</sub>. The termination reaction is [[catalysis|catalysed]] by the presence of certain free radicals, of which the most important are hydroxyl (OH), nitric oxide (NO) and atomic chlorine (Cl) and bromine (Br). In the second half of the 20th century, the amount of ozone in the stratosphere was [[ozone depletion|discovered to be declining]], mostly because of increasing concentrations of [[chlorofluorocarbon]]s (CFC) and similar [[haloalkane|chlorinated and brominated organic molecules]]. The concern over the health effects of the decline led to the 1987 [[Montreal Protocol]], the ban on the production of many [[ozone depletion|ozone-depleting]] chemicals and in the first and second decade of the 21st century the beginning of the recovery of stratospheric ozone concentrations.

====Importance to surface-dwelling life on Earth====
[[File:Ozone altitude UV graph.svg|thumb|upright=1.25|Levels of ozone at various altitudes and blocking of different bands of ultraviolet radiation. Essentially all UVC (100–280&nbsp;nm) is blocked by dioxygen (at 100–200&nbsp;nm) or by ozone (at 200–280&nbsp;nm) in the atmosphere. The shorter portion of this band and even more energetic UV causes the formation of the ozone layer, when single oxygen atoms produced by UV [[photolysis]] of dioxygen (below 240&nbsp;nm) react with more dioxygen. The ozone layer itself then blocks most, but not quite all, sunburn-producing UVB (280–315&nbsp;nm). The band of UV closest to visible light, UVA (315–400&nbsp;nm), is hardly affected by ozone, and most of it reaches the ground.]]

Ozone in the ozone layer filters out sunlight wavelengths from about 200&nbsp;nm UV rays to 315&nbsp;nm, with ozone peak absorption at about 250&nbsp;nm.<ref>{{cite journal |title=Photolysis of Atmospheric Ozone in the Ultraviolet Region |year=2003 |last1=Matsumi |first1=Yutaka |last2=Kawasaki |first2=Masahiro |journal=Chemical Reviews |volume=103 |issue=12 |pages=4767–82 |pmid=14664632 |doi=10.1021/cr0205255}} See the graphical absorption of ozone in two of its absorption bands, as a function of wavelength.</ref> This ozone UV absorption is important to life, since it extends the absorption of UV by ordinary oxygen and nitrogen in air (which absorb all wavelengths < 200&nbsp;nm) through the lower UV-C (200–280&nbsp;nm) and the entire UV-B band (280–315&nbsp;nm). The small unabsorbed part that remains of UV-B after passage through ozone causes sunburn in humans, and direct DNA damage in living tissues in both plants and animals. Ozone's effect on mid-range UV-B rays is illustrated by its effect on UV-B at 290&nbsp;nm, which has a radiation intensity 350 million times as powerful at the top of the atmosphere as at the surface. Nevertheless, enough of UV-B radiation at similar frequency reaches the ground to cause some sunburn, and these same wavelengths are also among those responsible for the production of [[vitamin D]] in humans.

The ozone layer has little effect on the longer UV wavelengths called UV-A (315–400&nbsp;nm), but this radiation does not cause sunburn or direct DNA damage. While UV-A probably does cause long-term skin damage in certain humans, it is not as dangerous to plants and to the health of surface-dwelling organisms on Earth in general (see [[ultraviolet]] for more information on near ultraviolet).

===Ground-level ozone===
{{Main|Ground-level ozone|Photochemical smog}}
{{Pollution sidebar|Natural}}

Ground-level ozone (or tropospheric ozone) is an atmospheric pollutant.<ref name=who-Europe>[http://www.euro.who.int/__data/assets/pdf_file/0005/112199/E79097.pdf Health Aspects of Air Pollution with Particulate Matter, Ozone and Nitrogen Dioxide] {{Webarchive|url=https://web.archive.org/web/20120414204626/http://www.euro.who.int/__data/assets/pdf_file/0005/112199/E79097.pdf |date=2012-04-14}}. WHO-Europe report 13–15 January 2003 (PDF)</ref> It is not emitted directly by [[internal combustion engine|car engines]] or by industrial operations, but formed by the reaction of sunlight on air containing [[volatile organic compound|hydrocarbons]] and [[nitrogen oxide]]s that react to form ozone directly at the source of the pollution or many kilometers downwind.

Ozone reacts directly with some hydrocarbons such as [[aldehyde]]s and thus begins their removal from the air, but the products are themselves key components of [[photochemical smog|smog]]. Ozone [[photolysis]] by UV light leads to production of the [[hydroxyl radical]] HO• and this plays a part in the removal of hydrocarbons from the air, but is also the first step in the creation of components of smog such as [[peroxyacyl nitrates]], which can be powerful eye irritants. The atmospheric lifetime of tropospheric ozone is about 22 days; its main removal mechanisms are being deposited to the ground, the above-mentioned reaction giving HO•, and by reactions with OH and the peroxy radical HO<sub>2</sub>•.<ref>{{cite journal |author=Stevenson |year=2006 |title=Multimodel ensemble simulations of present-day and near-future tropospheric ozone |journal=Journal of Geophysical Research: Atmospheres |volume=111 |issue=D8 |publisher=[[American Geophysical Union]] |doi=10.1029/2005JD006338 |bibcode=2006JGRD..111.8301S |display-authors=etal |url=http://www.agu.org/pubs/crossref/2006/2005JD006338.shtml |access-date=2006-09-16 |archive-url=https://web.archive.org/web/20111104195423/http://www.agu.org/pubs/crossref/2006/2005JD006338.shtml |archive-date=2011-11-04}}</ref>

There is evidence of significant reduction in agricultural yields because of increased ground-level ozone and pollution which interferes with [[photosynthesis]] and stunts overall growth of some plant species.<ref>{{cite web |title=Rising Ozone Levels Pose Challenge to U.S. Soybean Production, Scientists Say |date=2003-07-31 |publisher=NASA Earth Observatory |url=http://earthobservatory.nasa.gov/Newsroom/view.php?id=23565 |access-date=2006-05-10 |archive-url=https://web.archive.org/web/20100316221804/http://earthobservatory.nasa.gov/Newsroom/view.php?id=23565 |archive-date=2010-03-16}}</ref><ref name="arb.ca.gov">{{cite web |last=Mutters |first=Randall |title=Statewide Potential Crop Yield Losses From Ozone Exposure |date=March 1999 |publisher=California Air Resources Board |url=http://www.arb.ca.gov/research/abstracts/94-345.htm |access-date=2006-05-10 |archive-url=https://web.archive.org/web/20040217151427/http://www.arb.ca.gov/research/abstracts/94-345.htm |archive-date=2004-02-17}}</ref> The [[United States Environmental Protection Agency]] (EPA) has proposed a secondary regulation to reduce crop damage, in addition to the primary regulation designed for the protection of human health.

====Ground-level ozone in urban areas====
Certain examples of cities with elevated ozone readings are [[Denver|Denver, Colorado]]; [[Houston, Texas]]; and [[Mexico City]], [[Mexico]]. Houston has a reading of around 41&nbsp;nmol/mol, while Mexico City is far more hazardous, with a reading of about 125&nbsp;nmol/mol.<ref name="arb.ca.gov"/>

Ground-level ozone, or tropospheric ozone, is the most concerning type of ozone pollution in urban areas and is increasing in general.<ref>{{cite book |title=Rethinking the Ozone Problem in Urban and Regional Air Pollution |date=1991-01-01 |isbn=978-0-309-04631-2 |doi=10.17226/1889 |url=https://archive.org/details/rethinkingozonep0000unse |url-access=registration}}</ref> Ozone pollution in urban areas affects denser populations, and is worsened by high populations of vehicles, which emit pollutants NO<sub>2</sub> and [[volatile organic compound|VOCs]], the main contributors to problematic ozone levels.<ref name="Sharma-2016">{{cite journal |last1=Sharma |first1=Sumit |last2=Sharma |first2=Prateek |last3=Khare |first3=Mukesh |last4=Kwatra |first4=Swati |title=Statistical behavior of ozone in urban environment |date=May 2016 |journal=Sustainable Environment Research |volume=26 |issue=3 |pages=142–148 |bibcode= 2016SusER..26..142S|doi=10.1016/j.serj.2016.04.006 |doi-access=free}}</ref> Ozone pollution in urban areas is especially concerning with increasing temperatures, raising heat-related mortality during [[heat wave]]s.<ref>{{cite journal |last1=Diem |first1=Jeremy E. |last2=Stauber |first2=Christine E. |last3=Rothenberg |first3=Richard |date=2017-05-16 |editor-last=Añel |editor-first=Juan A. |title=Heat in the southeastern United States: Characteristics, trends, and potential health impact |journal=PLOS ONE |volume=12 |issue=5 |pages=e0177937 |issn=1932-6203 |bibcode=2017PLoSO..1277937D |pmid=28520817 |doi=10.1371/journal.pone.0177937 |doi-access=free |pmc=5433771}}</ref> During heat waves in urban areas, [[ground level ozone]] pollution can be 20% higher than usual.<ref>{{cite journal |last1=Hou |first1=Pei |last2=Wu |first2=Shiliang |title=Long-term Changes in Extreme Air Pollution Meteorology and the Implications for Air Quality |date=July 2016 |journal=Scientific Reports |volume=6 |issue=1 |page=23792 |issn=2045-2322 |bibcode=2016NatSR...623792H |pmid=27029386 |doi=10.1038/srep23792 |pmc=4815017}}</ref> Ozone pollution in urban areas reaches higher levels of exceedance in the summer and autumn, which may be explained by weather patterns and traffic patterns.<ref name="Sharma-2016"/> People experiencing poverty are more affected by pollution in general, even though these populations are less likely to be contributing to pollution levels.<ref>{{cite journal |last1=Tessum |first1=Christopher W. |last2=Apte |first2=Joshua S. |last3=Good kind |first3=Andrew L. |last4=Muller |first4=Nicholas Z. |last5=Mullins |first5=Kimberley A. |last6=Paolella |first6=David A. |last7=Polasky |first7=Stephen |last8=Springer |first8=Nathaniel P. |last9=Thakrar |first9=Sumil K. |title=Inequity in consumption of goods and services adds to racial–ethnic disparities in air pollution exposure |date=2019-03-11 |journal=Proceedings of the National Academy of Sciences |volume=116 |issue=13 |pages=6001–6006 |bibcode=2019PNAS..116.6001T |issn=0027-8424 |pmid=30858319 |doi=10.1073/pnas.1818859116 |doi-access=free |pmc=6442600}}</ref>

As mentioned above, Denver, Colorado, is one of the many cities in the U.S. that have high amounts of ozone. According to the [[American Lung Association]], the [[Denver–Aurora combined statistical area|Denver–Aurora area]] is the 14th most ozone-polluted area in the U.S.<ref>American Lung Association. (n.d.). How healthy is the air you breathe? Retrieved March 20, 2019, from [https://www.lung.org/our-initiatives/healthy-air/sota/city-rankings/most-polluted-cities.html lung.org]</ref> The problem of high ozone levels is not new to this area. In 2004, the EPA allotted the [[Denver metropolitan area|Denver Metro]]/North Front Range{{efn|This includes Adams, Arapahoe, Boulder, Broomfield, Denver, Douglas, Jefferson, and parts of Larimer and Weld counties.}} as [[non-attainment area]]s per 1997's 8-hour ozone standard,<ref>{{cite web |title=History of ozone in Colorado |website=Colorado Department of Public Health & Environment |url=https://cdphe.colorado.gov/history-of-ozone-in-colorado |access-date=2023-04-18}}</ref> but later deferred this status until 2007. The non-attainment standard indicates that an area does not meet the EPA's air quality standards. The Colorado Ozone Action Plan was created in response, and numerous changes were implemented from this plan. The first major change was that car emission testing was expanded across the state to more counties that did not previously mandate emissions testing, like areas of Larimer and Weld County. There have also been changes made to decrease Nitrogen Oxides (NOx) and [[Volatile Organic Compound]] (VOC) emissions, which should help lower ozone levels.

One large contributor to high ozone levels in the area is the oil and [[natural gas]] industry situated in the Denver-Julesburg Basin (DJB) which overlaps with a majority of Colorado's metropolitan areas. Ozone is produced naturally in the Earth's stratosphere, but is also produced in the troposphere from human efforts. Briefly mentioned above, NOx and VOCs react with sunlight to create ozone through a process called photochemistry. One hour elevated ozone events (<75&nbsp;ppb) "occur during June–August indicating that elevated ozone levels are driven by regional photochemistry".<ref name="Evans-2017">{{cite journal |last1=Evans |first1=Jason M. |last2=Helmig |first2=Detlev |title=Investigation of the influence of transport from oil and natural gas regions on elevated ozone levels in the northern Colorado front range |date=February 2017 |journal=Journal of the Air & Waste Management Association |volume=67 |issue=2 |pages=196–211 |bibcode=2017JAWMA..67..196E |issn=1096-2247 |pmid=27629587 |doi=10.1080/10962247.2016.1226989 |doi-access=free}}</ref> According to an article from the University of Colorado-Boulder, "Oil and natural gas VOC emission have a major role in ozone production and bear the potential to contribute to elevated O<sub>3</sub> levels in the Northern Colorado Front Range (NCFR)".<ref name="Evans-2017"/> Using complex analyses to research wind patterns and emissions from large oil and natural gas operations, the authors concluded that "elevated O<sub>3</sub> levels in the NCFR are predominantly correlated with air transport from N– ESE, which are the upwind sectors where the O&NG operations in the Wattenberg Field area of the DJB are located".<ref name="Evans-2017"/>

Contained in the Colorado Ozone Action Plan, created in 2008, plans exist to evaluate "emission controls for large industrial sources of NOx" and "statewide control requirements for new oil and gas condensate tanks and pneumatic valves".<ref>{{cite web |title=Colorado Ozone Action Plan |author=((Colorado Department of Public Health and Environment, Regional Air Quality Council, & North Front Range Metropolitan Planning Organization)) |url=https://massless.info/images/AP_PO_Denver-Ozone-Action-Plan-2008.pdf |access-date=2019-03-21}}</ref> In 2011, the Regional Haze Plan was released that included a more specific plan to help decrease NOx emissions. These efforts are increasingly difficult to implement and take many years to come to pass. Of course there are also other reasons that ozone levels remain high. These include: a growing population meaning more car emissions, and the mountains along the NCFR that can trap emissions. If interested, daily air quality readings can be found at the Colorado Department of Public Health and Environment's website.<ref>Colorado Department of Public Health and Environment. (n.d.). Colorado Air Quality. Retrieved March 20, 2019, from https://www.colorado.gov/airquality/air_quality.aspx</ref> As noted earlier, Denver continues to experience high levels of ozone to this day. It will take many years and a systems-thinking approach to combat this issue of high ozone levels in the Front Range of Colorado.

====Ozone cracking====
{{Main|Ozone cracking}}
[[File:Ozone cracks in tube1.jpg|thumb|Ozone cracking in [[natural rubber]] tubing]]
Ozone gas attacks any [[polymer]] possessing olefinic or [[double bond]]s within its chain structure, such as [[natural rubber]], [[nitrile rubber]], and [[styrene-butadiene]] rubber. Products made using these polymers are especially susceptible to attack, which causes cracks to grow longer and deeper with time, the rate of crack growth depending on the load carried by the rubber component and the concentration of ozone in the atmosphere. Such materials can be protected by adding [[antiozonant]]s, such as waxes, which bond to the surface to create a protective film or blend with the material and provide long term protection. [[Ozone cracking]] used to be a serious problem in car tires,<ref>{{cite journal |last1=Layer |first1=Robert W. |last2=Lattimer |first2=Robert P. |title=Protection of Rubber against Ozone |journal=Rubber Chemistry and Technology |date=July 1990 |volume=63 |number=3 |pages=426–450 |doi=10.5254/1.3538264}}</ref> for example, but it is not an issue with modern tires. On the other hand, many critical products, like [[gasket]]s and [[O-ring]]s, may be attacked by ozone produced within compressed air systems. [[Fuel line]]s made of reinforced rubber are also susceptible to attack, especially within the engine compartment, where some ozone is produced by electrical components. Storing rubber products in close proximity to a [[Direct Current|DC]] [[electric motor]] can accelerate ozone cracking. The [[commutator (electric)|commutator]] of the motor generates sparks which in turn produce ozone.

===Ozone as a greenhouse gas===
[[File:1950- Ozone in upper and lower troposphere.svg|thumb|Ozone with an anthropogenic "fingerprint" contributes to global warming and climate change, especially when present in the upper troposphere.<ref>{{cite journal |last1=Yu |first1=Xinyuan |last2=Fiore |first2=Arlene M. |last3=Santer |first3=Benjamin D. |last4=Correa |first4=Gustavo P. |last5=Lamarque |first5=Jean-Francois |last6=Ziemke |first6=Jerald R. |last7=Eastham |first7=Sebastian d. |last8=Zhu |first8=Qindan |display-authors=4 |title=Anthropogenic Fingerprint Detectable in Upper Tropospheric Ozone Trends Retrieved from Satellite |journal=Environmental Science and Technology |date=2 August 2024 |volume=58 |issue=32 |pages=14306–14317 |doi=10.1021/acs.est.4c01289 |doi-access=free |pmid=39092829 |pmc=11325641|bibcode=2024EnST...5814306Y }} Further explained by {{cite web |last1=Chu |first1=Jennifer |title=Scientists find a human 'fingerprint' in the upper troposphere's increasing ozone |date=2 August 2024 |website=Phys.org |url=https://phys.org/news/2024-08-scientists-human-fingerprint-upper-troposphere.html|url-status=live |archive-url=https://web.archive.org/web/20240802154244/https://phys.org/news/2024-08-scientists-human-fingerprint-upper-troposphere.html |archive-date=2 August 2024}}</ref>]]
Although ozone was present at ground level before the [[Industrial Revolution]], peak concentrations are now far higher than the pre-industrial levels, and even background concentrations well away from sources of pollution are substantially higher.<ref>{{cite web |year=1998 |title=Tropospheric Ozone in EU – The consolidated report |publisher=European Environmental Agency |url=http://www.eea.europa.eu/publications/TOP08-98/page004.html |access-date=2006-05-10}}</ref><ref>{{cite web |title=Atmospheric Chemistry and Greenhouse Gases |publisher=Intergovernmental Panel on Climate Change |url=http://www.grida.no/climate/ipcc_tar/wg1/142.htm |access-date=2006-05-10 |archive-url=https://web.archive.org/web/20060710143636/http://www.grida.no/climate/ipcc_tar/wg1/142.htm |archive-date=2006-07-10}}</ref> Ozone acts as a [[greenhouse gas]], absorbing some of the [[infrared]] energy emitted by the earth. Quantifying the greenhouse gas potency of ozone is difficult because it is not present in uniform concentrations across the globe. However, the most widely accepted scientific assessments relating to [[climate change]] (e.g. the [[Intergovernmental Panel on Climate Change]] [[Third Assessment Report]])<ref>{{cite web |year=2001 |title=Climate Change 2001 |publisher=Intergovernmental Panel on Climate Change |url=http://www.grida.no/climate/ipcc_tar/ |access-date=2006-09-12 |archive-url=https://web.archive.org/web/20060913043522/http://www.grida.no/climate/ipcc_tar/ |archive-date=2006-09-13}}</ref> suggest that the [[radiative forcing]] of tropospheric ozone is about 25% that of [[carbon dioxide]].

The annual [[global warming potential]] of tropospheric ozone is between 918 and 1022 tons [[carbon dioxide equivalent]]/tons tropospheric ozone. This means on a per-molecule basis, ozone in the troposphere has a [[radiative forcing]] effect roughly 1,000 times as strong as [[carbon dioxide]]. However, tropospheric ozone is a short-lived greenhouse gas, which decays in the atmosphere much more quickly than [[carbon dioxide]]. This means that over a 20-year span, the global warming potential of tropospheric ozone is much less, roughly 62 to 69 tons [[carbon dioxide equivalent]] / ton tropospheric ozone.<ref>Life Cycle Assessment Methodology Sufficient to Support Public Declarations and Claims, Committee Draft Standard, Version 2.1. Scientific Certification Systems, February 2011. Annex B, Section 4.</ref>

Because of its short-lived nature, tropospheric ozone does not have strong global effects, but has very strong radiative forcing effects on regional scales. In fact, there are regions of the world where tropospheric ozone has a [[radiative forcing]] up to 150% of [[carbon dioxide]].<ref>[http://acdb-ext.gsfc.nasa.gov/Data_services/cloud_slice/ NASA GODDARD HOMEPAGE FOR TROPOSPHERIC OZONE NASA Goddard Space Flight Center Code 613.3, Chemistry and Dynamics Branch]. Acdb-ext.gsfc.nasa.gov (2006-09-20). Retrieved on 2012-02-01.</ref> For example, ozone increase in the [[troposphere]] is shown to be responsible for ~30% of upper [[Southern Ocean]] [[ocean heat content|interior warming]] between 1955 and 2000.<ref>{{cite journal |last1=Liu |first1=Wei |last2=Hegglin |first2=Michaela I. |last3=Checa-Garcia |first3=Ramiro |last4=Li |first4=Shouwei |last5=Gillett |first5=Nathan P. |last6=Lyu |first6=Kewei |last7=Zhang |first7=Xuebin |last8=Swart |first8=Neil C. |title=Stratospheric ozone depletion and tropospheric ozone increases drive Southern Ocean interior warming |journal=Nature Climate Change |date=April 2022 |volume=12 |issue=4 |pages=365–372 |bibcode=2022NatCC..12..365L |language=en |issn=1758-6798 |doi=10.1038/s41558-022-01320-w |s2cid=247844868 |url=https://www.researchgate.net/publication/359643522 |url-access=subscription}}<br>Lay summary report: {{cite news |title=Ozone may be heating the planet more than we realize |work=[[University of Reading]] |language=en |url=https://phys.org/news/2022-03-ozone-planet.html |access-date=19 April 2022}}</ref>