Editing Polystyrene (section)

==Environmental issues==

===Production===
Polystyrene foams are produced using blowing agents that form bubbles and expand the foam. In expanded polystyrene, these are usually hydrocarbons such as [[pentane]], which may pose a flammability hazard in manufacturing or storage of newly manufactured material, but have relatively mild environmental impact.{{citation needed|date=June 2015}} Extruded polystyrene is usually made with [[hydrofluorocarbon]]s ([[HFC-134a]]),<ref>[http://www.earthresource.org/campaigns/capp/capp-styrofoam.html Polystyrene Foam Report] {{webarchive|url=https://web.archive.org/web/20130325091953/http://www.earthresource.org/campaigns/capp/capp-styrofoam.html |date=25 March 2013 }}. Earth Resource Foundation.</ref> which have global warming potentials of approximately 1000–1300 times that of carbon dioxide.<ref>[http://www.epa.gov/ozone/geninfo/gwps.html Global Warming Potentials of ODS Substitutes]. EPA.gov</ref> In Europe, where HFC-134a was banned since beginning 2022, XPS is produced using carbon dioxide as blowing agent, achieving an ODP (Ozone depletion potential) of 0 and a GWP (Global warming potential) below 5.Packaging, particularly expanded polystyrene, is a contributor of [[microplastics]] from both land and maritime activities.<ref>{{Cite web |last=Environment |first=U. N. |date=2021-10-21 |title=Drowning in Plastics – Marine Litter and Plastic Waste Vital Graphics |url=http://www.unep.org/resources/report/drowning-plastics-marine-litter-and-plastic-waste-vital-graphics |access-date=2022-03-21 |website=UNEP - UN Environment Programme |language=en}}</ref>

===Environmental degradation===
Polystyrene is not [[biodegradeable]] but it is susceptible to [[Photo-oxidation of polymers|photo-oxidation]].<ref>{{cite journal |last1=Yousif |first1=Emad |last2=Haddad |first2=Raghad |title=Photodegradation and photostabilization of polymers, especially polystyrene: review |journal=SpringerPlus |date=December 2013 |volume=2 |issue=1 |pages=398 |doi=10.1186/2193-1801-2-398 |pmid=25674392 |pmc=4320144 |doi-access=free}}</ref> For this reason commercial products contain [[Polymer stabilizers|light stabilizers]].

===Litter===
[[File:Physical weathering styrofoam cup Lake MIchigan.jpg|thumb|Discarded polystyrene cup on the shore of [[Lake Michigan]]]]
Animals do not recognize polystyrene foam as an artificial material and may even mistake it for food.<ref name="Hofer 2008 59">{{cite book|last=Hofer|first=Tobias N.|title=Marine pollution: new research|year=2008|publisher=Nova Science Publishers|location=New York|isbn=978-1-60456-242-2|page=59}}</ref>
Polystyrene foam blows in the wind and floats on water due to its low specific gravity.  It can have serious effects on the health of birds and marine animals that swallow significant quantities.<ref name="Hofer 2008 59"/> Juvenile rainbow trout exposed to polystyrene fragments show toxic effects in the form of substantial histomorphometrical changes.<ref>{{cite journal |last1=Karbalaei |first1=Samaneh |last2=Hanachi |first2=Parichehr |last3=Rafiee |first3=Gholamreza |last4=Seifori |first4=Parvaneh |last5=Walker |first5=Tony R. |title=Toxicity of polystyrene microplastics on juvenile Oncorhynchus mykiss (rainbow trout) after individual and combined exposure with chlorpyrifos |journal=Journal of Hazardous Materials |date=September 2020 |volume=403 |pages=123980 |doi=10.1016/j.jhazmat.2020.123980 |pmid=33265019 |s2cid=224995527 |url=https://zenodo.org/record/4588238 }}</ref>

===Reducing===
{{Main|Phase-out of polystyrene foam}}
Restricting the use of foamed polystyrene takeout food packaging is a priority of many solid waste [[environmental organisation]]s.<ref>{{cite journal |doi=10.1016/j.marpolbul.2018.10.001 |pmid=30503422 |title=Reducing marine pollution from single-use plastics (SUPs): A review |journal=Marine Pollution Bulletin |volume=137 |pages=157–171 |year=2018 |last1=Schnurr |first1=Riley E.J. |last2=Alboiu |first2=Vanessa |last3=Chaudhary |first3=Meenakshi |last4=Corbett |first4=Roan A. |last5=Quanz |first5=Meaghan E. |last6=Sankar |first6=Karthikeshwar |last7=Srain |first7=Harveer S. |last8=Thavarajah |first8=Venukasan |last9=Xanthos |first9=Dirk |last10=Walker |first10=Tony R. |bibcode=2018MarPB.137..157S |s2cid=54522420 }}</ref> Efforts have been made to find alternatives to polystyrene, especially foam in restaurant settings. The original impetus was to eliminate [[chlorofluorocarbon]]s (CFC), which was a former component of foam.

====United States====
In 1987, [[Berkeley, California]], banned CFC food containers.<ref>{{cite news|title=Berkeley Barring Use of a Food Container|url=https://www.nytimes.com/1987/09/24/us/berkeley-barring-use-of-a-food-container.html?src=pm|access-date=23 December 2012|newspaper=[[The New York Times]]|date=24 September 1987|agency=[[Associated Press]]}}</ref> The following year, [[Suffolk County, New York]], became the first U.S. jurisdiction to ban polystyrene in general.<ref>{{cite news|title=Suffolk Votes A Bill to Ban Plastic Bags|url=https://www.nytimes.com/1988/03/30/nyregion/suffolk-votes-a-bill-to-ban-plastic-bags.html|access-date=23 December 2012|newspaper=The New York Times|date=30 March 1988}}</ref> However, legal challenges by the [[Society of the Plastics Industry]]<ref>{{cite news|last=Hevesi|first=Dennis|title=Ban on Plastics in Suffolk Is Overturned|url=https://www.nytimes.com/1990/03/04/nyregion/ban-on-plastics-in-suffolk-is-overturned.html?src=pm|access-date=23 December 2012|newspaper=The New York Times|date=4 March 1990}}</ref> kept the ban from going into effect until at last it was delayed when the Republican and Conservative parties gained the majority of the county legislature.<ref>{{cite news|last=Barbanel|first=Josh|title=Vote Blocks Plastics Ban For Suffolk|url=https://www.nytimes.com/1992/03/04/nyregion/vote-blocks-plastics-ban-for-suffolk.html|access-date=23 December 2012|newspaper=The New York Times|date=4 March 1992}}</ref> In the meantime, Berkeley became the first city to ban all foam food containers.<ref name="berkeley-1988"/> As of 2006, about one hundred localities in the United States, including [[Portland, Oregon]], and [[San Francisco]] had some sort of ban on polystyrene foam in restaurants. For instance, in 2007 [[Oakland, California]], required restaurants to switch to disposable food containers that would biodegrade if added to food compost.<ref>{{cite news|title=Styrofoam food packaging banned in Oakland|url=http://www.sfgate.com/news/article/Styrofoam-food-packaging-banned-in-Oakland-2516522.php|access-date=23 December 2012|newspaper=[[San Francisco Chronicle]]|date=28 June 2006|author=Herron Zamora, Jim }}</ref> In 2013, [[San Jose, California|San Jose]] became reportedly the largest city in the country to ban polystyrene foam food containers.<ref>{{cite web|last=Sanchez|first=Kris|title=San Jose Approves Styrofoam Ban|url=http://www.nbcbayarea.com/news/local/San-Jose-Set-to-Ban-Styrofoam-221354051.html|publisher=[[NBC]]|access-date=30 August 2013|date=27 August 2013}}</ref> Some communities have implemented wide polystyrene bans, such as [[Freeport, Maine]], which did so in 1990.<ref>{{cite web|title=CHAPTER 33 STYROFOAM ORDINANCE|url=http://www.freeportmaine.com/inc/scripts/file.php?file_id=1060|website=Ordinances|publisher=Town of Freeport, Maine|access-date=23 December 2012|archive-date=29 March 2014|archive-url=https://web.archive.org/web/20140329123453/http://freeportmaine.com/inc/scripts/file.php?file_id=1060|url-status=dead}}</ref> In 1988, the first U.S. ban of general polystyrene foam was enacted in Berkeley, California.<ref name="berkeley-1988">{{cite news|title=Berkeley Widens Ban on Foam Food Containers|url=https://www.latimes.com/archives/la-xpm-1988-06-16-mn-6881-story.html|access-date=23 December 2012|newspaper=The Los Angeles Times|date=16 June 1988}}</ref>

On 1 July 2015, [[New York City]] became the largest city in the United States to attempt to prohibit the sale, possession, and distribution of [[disposable product|single-use]] polystyrene foam (the initial decision was overturned on appeal).<ref>{{cite web |author=Tony Dokoupil |url=http://www.msnbc.com/new-york-city-foam-ban-overturned |title=msnbc.com |publisher=msnbc.com |date=2015-09-22 |access-date=2019-01-17 |archive-date=29 July 2018 |archive-url=https://web.archive.org/web/20180729015731/http://www.msnbc.com/new-york-city-foam-ban-overturned |url-status=dead }}</ref> In San Francisco, supervisors approved the toughest ban on "Styrofoam" (EPS) in the US which went into effect 1 January 2017. The city's Department of the Environment can make exceptions for certain uses like shipping medicines at prescribed temperatures.<ref>{{cite web| url=http://www.sfchronicle.com/bayarea/article/City-OKs-ban-on-Styrofoam-Jane-Kim-wants-to-play-8332796.php| title=S.F. supervisors OK toughest ban on foam packaging in U.S|access-date=2016-06-30| date=2016-06-30}}</ref>

The U.S. [[Green Restaurant Association]] does not allow polystyrene foam to be used as part of its certification standard.<ref>{{cite web | url=http://www.dinegreen.com/disposables-standard | title=Disposables Standard | publisher=Green Restaurant Association | access-date=14 December 2016}}</ref> Several green leaders, including the [[Ministry of the Environment|Dutch Ministry of the Environment]], advise people to reduce their environmental harm by using reusable coffee cups.<ref>{{cite news|author=Dineen, Shauna|title=The Throwaway Generation: 25 Billion Styrofoam Cups a Year|publisher=E-The Environmental Magazine|date=Nov–Dec 2005|url=http://www.emagazine.com/view/?2933|archive-url=https://web.archive.org/web/20061112142759/http://www.emagazine.com/view/?2933|url-status=dead|archive-date=2006-11-12}}</ref>

In March 2019, Maryland banned polystyrene foam food containers and became the first state in the country to pass a food container foam ban through the state legislature. Maine was the first state to officially get a foam food container ban onto the books.  In May 2019, Maryland Governor Hogan allowed the foam ban (House Bill 109) to become law without a signature making Maryland the second state to have a food container foam ban on the books, but is the first one to take effect on 1 July 2020.<ref>{{Cite web|url=https://news.bloombergenvironment.com/environment-and-energy/maryland-foam-packaging-ban-energy-bills-to-become-law|title=Maryland Foam Packaging Ban, Energy Bills to Become Law|last=Andrew M. Ballard|website=news.bloombergenvironment.com|language=en|access-date=2019-06-20}}</ref><ref>{{Cite web|url=https://environmentamerica.org/news/ame/statement-maryland-becomes-second-state-ban-plastic-foam-containers|title=Statement: Maryland becomes the second state to ban plastic foam containers|website=environmentamerica.org|language=en|access-date=2019-06-20|archive-date=11 July 2019|archive-url=https://web.archive.org/web/20190711024041/https://environmentamerica.org/news/ame/statement-maryland-becomes-second-state-ban-plastic-foam-containers|url-status=dead}}</ref><ref>{{Cite web|url=https://www.baltimoresun.com/politics/bs-md-hogan-bill-list-20190524-story.html|title=Maryland's new laws: banning foam food containers, raising tobacco-buying age, reforming UMMS board|last=The Sun|first=Baltimore|website=baltimoresun.com|date=24 May 2019 |language=en-US|access-date=2019-06-20}}</ref><ref>{{Cite web|url=http://www.mdlcv.org/2019-foam-ban|title=2019 Foam Ban|date=2019-05-30|website=Maryland League of Conservation Voters|language=en|access-date=2019-06-20|archive-date=20 June 2019|archive-url=https://web.archive.org/web/20190620002002/http://www.mdlcv.org/2019-foam-ban|url-status=dead}}</ref>

In September 2020, the New Jersey state legislature voted to ban disposable [[foam food container]]s and cups made of polystyrene foam.<ref>{{cite news |last1=Zaveri |first1=Mihir |title=Even Paper Bags Will Be Banned From N.J. Supermarkets |url=https://www.nytimes.com/2020/09/25/nyregion/nj-paper-plastic-bag-ban.html |access-date=22 November 2020 |work=[[The New York Times]] |date=25 September 2020}}</ref>

====Outside the United States====
[[File:火気厳禁 禁煙 (3715967341).jpg|thumb|Expanded polystyrene waste in Japan]]
[[China]] banned expanded polystyrene takeout/takeaway containers and tableware around 1999. However, compliance has been a problem and, in 2013, the Chinese plastics industry was lobbying for the ban's repeal.<ref>{{cite web|author1=Ying Sun, Nina  |author2=Toloken, Steve  |name-list-style=amp |title=China moves to end its 'ban' on PS food packaging|url=http://www.plasticsnews.com/article/20130321/NEWS/130329979/china-moves-to-end-its-ban-on-ps-food-packaging|website=Plastics News|access-date=10 June 2013|date=21 March 2013}}</ref>

[[India]] and [[Taiwan]] also banned polystyrene-foam food-service ware before 2007.<ref>{{cite web|last=Quan|first=Jean|title=letter to Public Works Committee|url=http://clerkwebsvr1.oaklandnet.com/attachments/13659.pdf|archive-url=https://web.archive.org/web/20061023152054/http://clerkwebsvr1.oaklandnet.com/attachments/13659.pdf|url-status=dead|archive-date=23 October 2006|access-date=26 January 2014|date=13 June 2006}}</ref>

The government of [[Zimbabwe]], through its Environmental Management Agency (EMA), banned polystyrene containers (popularly called 'kaylite' in the country), under Statutory Instrument 84 of 2012 (Plastic Packaging and Plastic Bottles) (Amendment) Regulations, 2012 (No 1.)
<ref>{{cite web|title=Government bans kaylite packaging|url=http://www.herald.co.zw/government-bans-kaylite-packaging-%e2%80%a2health-considerations-cited-%e2%80%a2defiant-citizens-face-prosecution/|work=The Herald|date=13 July 2017 |access-date=13 July 2017}}</ref>
<ref>{{cite web|title=Expanded polystyrene (kaylite): What are its impacts?|url=http://www.herald.co.zw/expanded-polystyrene-kaylite-what-are-its-impacts/|work=The Herald|date=12 July 2017 |access-date=13 July 2017}}</ref>

The city of [[Vancouver]], Canada, has announced its Zero Waste 2040 plan in 2018. The city will introduce bylaw amendments to prohibit business license holders from serving prepared food in polystyrene foam cups and take-out containers, beginning 1 June 2019.<ref>''[http://vancouver.ca/green-vancouver/single-use-items.aspx Single-Use Item Reduction Strategy, Zero Waste 2040]'' City of Vancouver, 2018</ref>

In 2019, the European Union voted to ban expanded polystyrene food packaging and cups, with the law officially going into effect in 2021.<ref>{{cite news |last1=Pyzyk |first1=Katie |title=European Parliament approves 2021 single-use plastics ban |url=https://www.wastedive.com/news/european-parliament-approves-2021-single-use-plastics-ban/551552/ |access-date=6 January 2022 |work=Waste Dive |date=March 29, 2019}}</ref><ref>{{cite web |title=Directive (EU) 2019/904 |url=https://eur-lex.europa.eu/legal-content/EN/TXT/HTML/?uri=CELEX:32019L0904&from=EN |website=Official Journal of the European Union |access-date=6 January 2022}}</ref>

[[Fiji]] passed the Environmental Management Bill in December 2020. Imports of polystyrene products were banned in January 2021.<ref>{{Cite web|title=Grace period for polystyrene products|url=https://www.fbcnews.com.fj/news/grace-period-for-polystyrene-products/|access-date=2020-12-12|website=Fiji Broadcasting Corporation}}</ref>

===Recycling===
[[File:Symbol_Resin_Code_6_PS.svg|class=skin-invert-image|thumb|90px|The [[resin identification code]] symbol for polystyrene<!--The [[Unicode]] character is U+2678, which will appear here if you have a suitable font installed: <span style="font-size:250%;">♸</span>.-->]]

In general, polystyrene is not accepted in [[curbside collection]] recycling programs and is not separated and recycled where it is accepted. In Germany, polystyrene is collected as a consequence of the packaging law (Verpackungsverordnung) that requires manufacturers to take responsibility for recycling or disposing of any packaging material they sell.

Most polystyrene products are currently not recycled due to the lack of incentive to invest in the compactors and logistical systems required. Due to the low density of polystyrene foam, it is not economical to collect. However, if the waste material goes through an initial compaction process, the material changes density from typically 30&nbsp;kg/m<sup>3</sup> to 330&nbsp;kg/m<sup>3</sup> and becomes a recyclable commodity of high value for producers of recycled plastic pellets. Expanded polystyrene scrap can be easily added to products such as EPS insulation sheets and other EPS materials for construction applications; many manufacturers cannot obtain sufficient scrap because of collection issues. When it is not used to make more EPS, foam scrap can be turned into products such as clothes hangers, park benches, flower pots, toys, rulers, stapler bodies, seedling containers, picture frames, and architectural molding from recycled PS.<ref>https://expandedpoly.co.uk/environment/ Polystyrene recycling. Retrieved 17 October 2019.</ref> As of 2016, around 100 tonnes of EPS are recycled every month in the UK.<ref>[http://ecclestons.com/expanded-polystyrene-recycling.htm EPS recycling.] {{Webarchive|url=https://web.archive.org/web/20201122023542/https://ecclestons.com/index.php?page=expanded-polystyrene-recycling.htm |date=22 November 2020 }} Eccleston & Hart Polystrene. Retrieved 21 July 2016.</ref>

Recycled EPS is also used in many metal casting operations. [[Rastra]] is made from EPS that is combined with cement to be used as an insulating amendment in the making of concrete foundations and walls. American manufacturers have produced insulating concrete forms made with approximately 80% recycled EPS since 1993.

=== Upcycling ===
A March 2022 joint study by scientists Sewon Oh and Erin Stache at Cornell University in Ithaca, New York found a new processing method of upcycling polystyrene to [[benzoic acid]]. The process involved irradiation of polystyrene with iron chloride and acetone under white light and oxygen for 20 hours.<ref name="refup">{{Cite journal |last1=Oh |first1=Sewon |last2=Stache |first2=Erin E. |date=2022-04-06 |title=Chemical Upcycling of Commercial Polystyrene via Catalyst-Controlled Photooxidation |url=https://pubs.acs.org/doi/10.1021/jacs.2c01411 |journal=Journal of the American Chemical Society |language=en |volume=144 |issue=13 |pages=5745–5749 |doi=10.1021/jacs.2c01411| pmid=35319868 |bibcode=2022JAChS.144.5745O |s2cid=247629479 |issn=0002-7863|url-access=subscription }}</ref> The scientists also demonstrated a similar scalable commercial process of upcycling polystyrene into valuable small-molecules (like benzoic acid) taking just a few hours.<ref name="refup"/>

===Incineration===
If polystyrene is properly incinerated at high temperatures (up to 1000&nbsp;°C<ref name="basfti2810d">BASF Technische Information TI 0/2-810d 81677 Juni 1989, Verwertungs- und Beseitigungsverfaren gebrauchter Schaumstoff-Verpackungen aus Styropor®</ref>) and with plenty of air<ref name="basfti2810d" /> (14 m<sup>3</sup>/kg{{Citation needed|date=July 2013}}), the chemicals generated are water, carbon dioxide, and possibly small amounts of residual halogen-compounds from flame-retardants.<ref name="basfti2810d"/> If only incomplete incineration is done, there will also be leftover carbon soot and a complex mixture of volatile compounds.<ref name=burning>[http://www.newton.dep.anl.gov/askasci/chem00/chem00053.htm Polystyrene Foam Burning Danger] {{Webarchive|url=https://web.archive.org/web/20150226223555/http://newton.dep.anl.gov/askasci/chem00/chem00053.htm |date=26 February 2015 }}. Newton.dep.anl.gov. Retrieved 25 December 2011.  Q and A page with an partially incorrect information.</ref>{{better source needed|reason=Q and A page with an incorrect information included|date=July 2013}} According to the [[American Chemistry Council]], when polystyrene is incinerated in modern facilities, the final volume is 1% of the starting volume; most of the polystyrene is converted into carbon dioxide, water vapor, and heat. Because of the amount of heat released, it is sometimes used as a power source for [[steam]] or [[electricity generation]].<ref name="basfti2810d"/><ref>{{Cite news|title = Ease of Disposal|url = http://www.americanchemistry.com/s_plastics/sec_pfpg.asp?CID=1434&did=5226|access-date = 25 June 2009|url-status = dead|archive-url = https://web.archive.org/web/20090607023527/http://americanchemistry.com/s_plastics/sec_pfpg.asp?CID=1434&DID=5226|archive-date = 7 June 2009}}</ref>

When polystyrene was burned at temperatures of 800–900&nbsp;°C (the typical range of a modern incinerator), the products of combustion consisted of "a complex mixture of [[polycyclic aromatic hydrocarbon]]s (PAHs) from alkyl benzenes to benzoperylene. Over 90 different compounds were identified in combustion effluents from polystyrene."<ref>{{cite journal |doi=10.1016/S0021-9673(01)90737-X |title=Products obtained during combustion of polymers under simulated incinerator conditions |journal=Journal of Chromatography A |volume=315 |pages=201–210 |year=1984 |last1=Hawley-Fedder |first1=R.A. |last2=Parsons |first2=M.L. |last3=Karasek |first3=F.W. }}  Quoted from a campaign site giving no details of the original source and experiment conditions.</ref>{{better source needed|reason=Quoted from a campaign site giving no details of the original source and experiment conditions, experiment may have been flawed or the campaign site may be misquoting|date=July 2013}} The American National Bureau of Standards Center for Fire Research found 57 chemical by-products released during the combustion of expanded polystyrene (EPS) foam.<ref>{{cite journal |last1=Gurman |first1=Joshua L. |title=Polystyrenes: A Review of the Literature on the Products of Thermal Decomposition and Toxicity |journal=Fire and Materials |date=1987 |volume=11 |issue=3 |pages=109–130 |url=https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=101741 |access-date=18 February 2021 |publisher=NIST|doi=10.1002/fam.810110302 |url-access=subscription }}</ref>