Seoul

===Air quality===
{{See also|Air pollution in South Korea}}
[[File:2015 PM2.5 Air Pollution Index in Seoul (hourly).png|thumb|right|{{Columns-start}}{{legend|#9900ac| Very Unhealthy }} {{legend|#ff0000| Unhealthy }} {{legend|#ff7e00| Unhealthy for sensitive groups }} {{Column}} {{legend|#ffff00| Moderate}} {{legend|#00e400|Good}} {{Columns-end}}According to the [[Environmental Performance Index]] 2016, South Korea ranked 173rd out of 180 countries in terms of air quality. More than 50 percent of the populations in South Korea are exposed to dangerous levels of fine dust.<ref>{{cite web |title=South Korea near bottom of world survey of air quality |date=16 May 2016 |publisher=[[The Korea Herald]] |url=http://www.koreaherald.com/view.php?ud=20160516000741 |quote=South Korea ranked 173rd out of 180 countries in terms of air quality, the Environmental Performance Index 2016 rankings showed Monday. ... A report said that 1.3 billion people exposed to poor air quality lived in East Asian countries, with more than 50 percent of the populations in South Korea and China exposed to dangerous levels of fine dust. |access-date=4 May 2017 |archive-date=2 April 2017 |archive-url=https://web.archive.org/web/20170402233407/http://www.koreaherald.com/view.php?ud=20160516000741 |url-status=live }}</ref><ref>{{Cite web|url=http://epi.yale.edu/country/south-korea|title=South Korea {{!}} Environmental Performance Index – Development|publisher=epi.yale.edu|language=en|access-date=4 May 2017|url-status=dead|archive-url=https://web.archive.org/web/20170507191325/http://epi.yale.edu/country/south-korea|archive-date=7 May 2017}}</ref>]]
[[Air pollution]] is a major issue in Seoul.<ref>Lee, Hyun-jeong. [http://www.koreaherald.com/view.php?ud=20150323000889 "Korea Wrestles with Growing Health Threat from Fined Dust"] {{Webarchive|url=https://web.archive.org/web/20170409113453/http://www.koreaherald.com/view.php?ud=20150323000889 |date=9 April 2017 }}. ''Korea Herald''. 23 March 2015. Retrieved 8 April 2017.</ref><ref name=npr>Hu, Elise. [https://www.npr.org/sections/parallels/2016/06/03/478796463/koreas-air-is-dirty-but-its-not-all-close-neighbor-chinas-fault "Korea's Air Is Dirty, But It's Not All Close-Neighbor China's Fault"] {{Webarchive|url=https://web.archive.org/web/20180809133256/https://www.npr.org/sections/parallels/2016/06/03/478796463/koreas-air-is-dirty-but-its-not-all-close-neighbor-chinas-fault |date=9 August 2018 }}. NPR. 3 June 2016. Retrieved 8 April 2017.</ref><ref>{{Cite news|url = https://www.bbc.com/news/blogs-news-from-elsewhere-34505628|title = Seoul's smelly gingko problem|work=[[BBC News]]|date = 12 October 2015|access-date = 16 February 2019|archive-date = 17 February 2019|archive-url = https://web.archive.org/web/20190217034736/https://www.bbc.com/news/blogs-news-from-elsewhere-34505628|url-status = live}}</ref><ref>{{Cite web|url = http://www.koreaherald.com/view.php?ud=20181003000213|title = &#91;Feature&#93; South Korea's odor pollution problem|date = 3 October 2018|access-date = 16 February 2019|archive-date = 17 February 2019|archive-url = https://web.archive.org/web/20190217030222/http://www.koreaherald.com/view.php?ud=20181003000213|url-status = live}}</ref> According to the 2016 [[World Health Organization]] Global Urban Ambient Air Pollution Database,<ref name=who>[https://www.who.int/phe/health_topics/outdoorair/databases/cities/en/ Global Urban Ambient Air Pollution Database.] {{Webarchive|url=https://web.archive.org/web/20190419180220/https://www.who.int/phe/health_topics/outdoorair/databases/cities/en/ |date=19 April 2019 }} World Health Organization. May 2016. Retrieved 8 April 2017.</ref> the annual average [[PM2.5]] concentration in 2014 was {{Convert|24|ug/m3||sp=us}}, which is 2.4 times higher than that recommended by the WHO [[Air quality guideline|Air Quality Guidelines]]<ref name=guidelines>[https://www.who.int/mediacentre/factsheets/fs313/en/ WHO Air Quality Guidelines.] {{Webarchive|url=https://web.archive.org/web/20180423114431/http://www.who.int/mediacentre/factsheets/fs313/en/ |date=23 April 2018 }} World Health Organization. September 2016. Retrieved 8 April 2017.</ref> for the annual mean PM2.5. The [[Seoul Metropolitan Government]] monitors and publicly shares real-time air quality data.<ref>[http://english.seoul.go.kr/policy-information/environment-energy/air-quality-information/1-air-quality-information/ Air Quality Information.] {{Webarchive|url=https://web.archive.org/web/20170410051914/http://english.seoul.go.kr/policy-information/environment-energy/air-quality-information/1-air-quality-information/ |date=10 April 2017 }} Seoul Metropolitan Government. Retrieved 8 April 2017.</ref>

Since the early 1960s, the [[Ministry of Environment (South Korea)|Ministry of Environment]] has implemented a range of policies and air pollutant standards to improve and manage air quality for its people.<ref name=policy>{{cite web|author=Yu-Jin Choi|author2=Woon-Soo Kim|url=https://www.seoulsolution.kr/en/content/changes-seoul’s-air-quality-control-policy|title=Changes in Seoul's Air Quality Control Policy|url-status=dead|archive-url=https://web.archive.org/web/20170906202717/https://www.seoulsolution.kr/en/content/changes-seoul%E2%80%99s-air-quality-control-policy|archive-date=6 September 2017|work=Seoul Solution|date=25 June 2015|access-date=12 April 2017}}</ref> The "Special Act on the Improvement of Air Quality in the Seoul Metropolitan Area" was passed in December 2003. Its 1st Seoul Metropolitan Air Quality Improvement Plan (2005–2014) focused on improving the concentrations of [[PM10]] and [[nitrogen dioxide]] by reducing emissions.<ref>[http://eng.me.go.kr/eng/web/index.do?menuId=235 1st Seoul Metropolitan Air Quality Improvement Plan.] {{Webarchive|url=https://web.archive.org/web/20170427003345/http://eng.me.go.kr/eng/web/index.do?menuId=235 |date=27 April 2017 }} Ministry of Environment, Republic of Korea. Retrieved 21 April 2017.</ref> As a result, the annual average PM10 concentrations decreased from 70.0 μg/m<sup>3</sup> in 2001 to 44.4 μg/m<sup>3</sup> in 2011<ref>{{Cite journal | doi=10.1016/j.envres.2015.05.029| pmid=26079317| bibcode=2015ER....140..684K|title = Effects of ambient air particles on mortality in Seoul: Have the effects changed over time?| journal=Environmental Research| volume=140| pages=684–690|year = 2015|last1 = Kim|first1 = Honghyok| last2=Kim| first2=Hyomi| last3=Lee| first3=Jong-Tae}}</ref> and 46 μg/m<sup>3</sup> in 2014.<ref name=who/> As of 2014, the annual average PM10 concentration was still at least twice than that recommended by the WHO Air Quality Guidelines.<ref name=guidelines/> The 2nd Seoul Metropolitan Air Quality Improvement Plan (2015–2024) added PM2.5 and [[ozone]] to its list of managed pollutants.<ref>[http://eng.me.go.kr/eng/web/index.do?menuId=238 2nd Seoul Metropolitan Air Quality Improvement Plan.] {{Webarchive|url=https://web.archive.org/web/20170426151808/http://eng.me.go.kr/eng/web/index.do?menuId=238 |date=26 April 2017 }} Ministry of Environment, Republic of Korea. Retrieved 21 April 2017.</ref>

[[Asian dust]], emissions from Seoul and in general from the rest of South Korea, as well as emissions from China, all contribute to Seoul's air quality.<ref name=npr/><ref>Chung, Anna. [http://www.centreasia.eu/sites/default/files/publications_pdf/note_ka2_anna_chung_march2014.pdf "Korea's policy towards pollution and fine particle: a sense of urgency"] {{webarchive|url=https://web.archive.org/web/20170427003611/http://www.centreasia.eu/sites/default/files/publications_pdf/note_ka2_anna_chung_march2014.pdf |date=27 April 2017 }}. Korea Analysis. v2. June 2014. Retrieved 21 April 2017.</ref> A partnership between researchers in South Korea and the United States is conducting an international air quality field study in Korea (KORUS-AQ) to determine how much each source contributes.<ref>{{Cite journal |last=Zastrow |first=Mark |date=6 May 2016 |title=NASA jet gets a sniff of pollution over South Korea |url=http://www.nature.com/news/nasa-jet-gets-a-sniff-of-pollution-over-south-korea-1.19875 |journal=Nature |doi=10.1038/nature.2016.19875 |s2cid=130657973 |access-date=26 April 2017 |archive-date=26 April 2017 |archive-url=https://web.archive.org/web/20170426155332/http://www.nature.com/news/nasa-jet-gets-a-sniff-of-pollution-over-south-korea-1.19875 |url-status=live }}</ref>{{Update inline|date=August 2023}}

Besides air quality, greenhouse gas emissions represent hot issues in South Korea since the country is among top-10 strongest emitters in the world. Seoul is the strongest hotspot of greenhouse gas emissions in the country and according to satellite data, the persistent carbon dioxide anomaly over the city is one of the strongest in the world.<ref>{{Cite journal|last1=Labzovskii|first1=Lev|last2=Jeong|first2=Su-Jong|last3=Parazoo|first3=Nicholas C.|date=2019|title=Working towards confident spaceborne monitoring of carbon emissions from cities using Orbiting Carbon Observatory-2|journal=Remote Sensing of Environment|volume=233|at=111359|doi=10.1016/j.rse.2019.111359|bibcode=2019RSEnv.23311359L|s2cid=202176909}}</ref>