Editing Smog (section)

===Coal===
Coal fire can emit significant clouds of smoke that contribute to the formation of winter smog. Coal fires can be used to heat individual buildings or to provide energy in a power-producing plant. Air pollution from this source has been reported in England since the [[Middle Ages]].<ref name="middleages3">{{cite web|url=http://www.environmentalgraffiti.com/offbeat-news/environmentalism-in-1306/725|title=Environmentalism in 1306|author=Chris|year=2007|publisher=By Environmental Graffiti|archive-url=https://web.archive.org/web/20080725090103/http://www.environmentalgraffiti.com/offbeat-news/environmentalism-in-1306/725|archive-date=25 July 2008|url-status=dead}}</ref><ref name="middleages22">{{cite web|url=http://scribol.com/art-and-design/green-design/environmentalism-in-1306/|title=Environmentalism in 1306|author=Karl|year=2008|publisher=By Environmental Graffiti|access-date=17 February 2017|archive-date=13 November 2019|archive-url=https://web.archive.org/web/20191113013723/https://scribol.com/art-and-design/green-design/environmentalism-in-1306/|url-status=dead}}</ref> London, in particular, was notorious up through the mid-20th century for its coal-caused smogs, which were nicknamed "[[Pea soup fog|pea-soupers]]". Air pollution of this type is still a problem in areas that generate significant smoke from burning coal. The emissions from coal combustion are one of the main causes of [[air pollution in China]].<ref>{{cite book|url=https://www.merics.org/en/merics-analysis/chinas-political-system/|title=China's Political System|editor-last=Heilmann|editor-first=Sebastian |publisher=Rowman & Littlefield|year=2017|page=360|archive-url=https://web.archive.org/web/20161011093650/http://www.merics.org/en/merics-analysis/chinas-political-system/|archive-date=11 October 2016|url-status=dead}}</ref> Especially during autumn and winter when coal-fired heating ramps up, the amount of produced smoke at times forces some Chinese cities to close down roads, schools or airports. One prominent example for this was China's Northeastern city of [[2013 Harbin smog|Harbin in 2013]].