Great Smog of London

The Great Smog of London, or Great Smog of 1952, was a severe air-pollution event that affected the British capital of London in early December 1952. A period of cold weather, combined with an anticyclone and windless conditions, collected airborne pollutants—mostly arising from the use of coal—to form a thick layer of smog over the city. It lasted from Friday 5 December to Tuesday 9 December 1952, and dispersed quickly when the weather changed.

Great Smog of London
Nelson's Column during the Great Smog of 1952.jpg
Nelson's Column during the Great Smog
Date5–9 December 1952 (1952-12-05 – 1952-12-09)
LocationLondon, England
Coordinates51°30′25″N 0°07′37″W / 51.507°N 0.127°W / 51.507; -0.127Coordinates: 51°30′25″N 0°07′37″W / 51.507°N 0.127°W / 51.507; -0.127
up to 12,000 dead[1][2]
100,000 medical conditions[citation needed]

It caused major disruption by reducing visibility and even penetrating indoor areas, far more severely than previous smog events experienced in the past, called "pea-soupers". Government medical reports in the following weeks, however, estimated that up until 8 December, 4,000 people had died as a direct result of the smog and 100,000 more were made ill by the smog's effects on the human respiratory tract.[citation needed] More recent research suggests that the total number of fatalities may have been considerably greater, one paper suggesting about 6,000 more died in the following months as a result of the event.[3]

London has suffered since the 13th century from poor air quality,[4] which worsened in the 1600s,[5][6] but the Great Smog is known to be the worst air-pollution event in the history of the United Kingdom,[7] and the most significant in terms of its effect on environmental research, government regulation, and public awareness of the relationship between air quality and health.[3][5] It led to several changes in practices and regulations, including the Clean Air Act 1956.


Sources of pollutionEdit

The cold weather preceding and during the Great Smog led Londoners to burn more coal than usual to keep themselves warm. Post-war domestic coal tended to be of a relatively low-grade, sulphurous variety (similar to lignite), while conversely, better-quality "hard" coals (such as anthracite coal) tended to be exported to pay off World War II debts,[8] which increased the amount of sulphur dioxide in the smoke. There were also numerous coal-fired power stations in the Greater London area, including Fulham, Battersea, Bankside, Greenwich and Kingston upon Thames, all of which added to the pollution. According to the UK's Met Office, the following pollutants were emitted each day during the smoggy period: 1,000 tonnes of smoke particles, 140 tonnes of hydrochloric acid, 14 tonnes of fluorine compounds, and 370 tonnes of sulfur dioxide which may have been converted to 800 tonnes of sulphuric acid.[9] Research suggests that additional pollution-prevention systems fitted at Battersea may have worsened the air quality. Flue-gas washing reduced the temperature of the flue-gases so they did not rise but instead slumped to a ground level causing a local nuisance.[10]

Additionally, there was pollution and smoke from vehicle exhaust—particularly from steam locomotives and diesel-fuelled buses, which had replaced the recently abandoned electric tram system. Other industrial and commercial sources also contributed to the air pollution.[11]


On 4 December 1952, an anticyclone settled over a windless London, causing a temperature inversion with cold, stagnant air trapped under a layer (or "lid") of warm air.[12][13] The resultant fog, mixed with smoke from home and industrial chimneys, particulates such as those from motor vehicle exhausts, and other pollutants such as sulphur dioxide, formed a persistent smog, which blanketed the capital the following day. The presence of tarry particles of soot gave the smog its yellow-black colour hence the nickname "pea-souper".[11] The absence of significant wind prevented its dispersal and allowed an unprecedented accumulation of pollutants.[citation needed]


Effect on LondonEdit

Although London was accustomed to heavy fogs, this one was denser and longer-lasting than any previous fog.[14] Visibility was reduced to a few meters ("It's like you were blind"[15]) making driving difficult or impossible.

Public transport ceased, apart from the London Underground, and the ambulance service stopped, forcing users to transport themselves to the hospital. The smog was so dense that it even seeped indoors, resulting in cancellation or abandonment of concerts and film screenings as visibility decreased in large enclosed spaces, and stages and screens became harder to see from the seats.[16] Outdoor sports events were also cancelled.[17]

In the inner London suburbs and away from town centers, there was no disturbance by moving traffic to thin out the dense fog in the back streets. The result was that visibility could be down to a meter or so in the daytime. Walking out of doors became a matter of shuffling one's feet to feel for potential obstacles such as road curbs. This was made even worse at night since each back street lamp at the time was fitted with an incandescent light-bulb, which gave no penetrating light onto the pavement for pedestrians to see their feet or even the lamp post. Fog-penetrating fluorescent lamps did not become widely available until later in the 1950s. "Smog masks" were worn by those who were able to purchase them from chemists.[citation needed]

Near railway lines, on which "fog working" was implemented, loud explosions similar to a shotgun shot were common. The explosions were made by "detonators"—a form of large percussion cap placed on the track and activated by the wheels of trains. These devices were placed by certain signals to provide an audible warning to match the visual indication provided by the signal for the driver.[citation needed]

Health effectsEdit

There was no panic, as London was infamous for its fog. In the weeks that ensued, however, statistics compiled by medical services found that the fog had killed 4,000 people.[18] Most of the victims were very young or elderly, or had pre-existing respiratory problems. In February 1953, Marcus Lipton suggested in the House of Commons that the fog had caused 6,000 deaths and that 25,000 more people had claimed sickness benefits in London during that period.[19]

Mortality remained elevated for months after the fog. A preliminary report, never finalised, blamed those deaths on an influenza epidemic.[3] Emerging evidence revealed that only a fraction of the deaths could be from influenza.[20] Most of the deaths were caused by respiratory tract infections, from hypoxia and as a result of mechanical obstruction of the air passages by pus arising from lung infections caused by the smog.[21][22][23] The lung infections were mainly bronchopneumonia or acute purulent bronchitis superimposed upon chronic bronchitis.[24][25]

More recent research suggests that the number of fatalities was considerably greater than contemporary estimates, at about 12,000.[3][26]..

Environmental impactEdit

The death toll formed an important impetus to modern environmentalism, and it caused a rethinking of air pollution, as the smog had demonstrated its lethal potential. New regulations were implemented, restricting the use of dirty fuels in industry and banning black smoke.[citation needed]

Environmental legislation since 1952, such as the City of London (Various Powers) Act 1954 and the Clean Air Acts of 1956 and 1968, led to a reduction in air pollution. Financial incentives were offered to householders to replace open coal fires with alternatives (such as installing gas fires), or for those who preferred, to burn coke instead which produces minimal smoke. Central heating (using gas, electricity, oil or permitted solid fuel) was rare in most dwellings at that time, not finding favor until the late 1960s onwards. Despite improvements, insufficient progress had been made to prevent one further smog event approximately ten years later, in early December 1962.[27]


Atmospheric scientists at Texas A&M University investigating the haze of polluted air in Beijing realized that their research led to a possible cause for the London event in 1952. "By examining conditions in China and experimenting in a lab, the scientists suggest that a combination of weather patterns and chemistry could have caused London fog to turn into a haze of concentrated sulphuric acid."[28]

See alsoEdit


  1. ^ "The lethal effects of London fog". BBC News. 22 December 2015.
  2. ^ "In 1952 London, 12,000 people died from smog — here's why that matters now". The Verge. 16 December 2017.
  3. ^ a b c d Bell, M.L.; Davis, D.L.; Fletcher, T. (2004). "A Retrospective Assessment of Mortality from the London Smog Episode of 1952: The Role of Influenza and Pollution". Environ Health Perspect. 112 (1, January): 6–8. doi:10.1289/ehp.6539. PMC 1241789. PMID 14698923.
  4. ^ Brimblecombe, Peter (1976). "Attitudes and Responses Towards Air Pollution in Medieval England". Journal of the Air Pollution Control Association. 26 (10): 941–45. doi:10.1080/00022470.1976.10470341. PMID 789426.
  5. ^ a b Evelyn, John; Pegge, Samuel, 1704–1796, (ed.) (1661), Fumifugium, Printed by W. Godbid, retrieved 5 May 2016CS1 maint: multiple names: authors list (link) CS1 maint: extra text: authors list (link)
  6. ^ Graunt, John, 1620–1674; Petty, William, Sir, 1623–1687 (1662), Natural and political observations mentioned in a following index, and made upon the bills of mortality [microform] / by John Graunt ... ; with reference to the government, religion, trade, growth, ayre, diseases, and the several changes of the said city, Printed by Tho. Roycroft for John Martin, James Allestry, and Tho. Dicas
  7. ^ McKie, Robin & Townsend, Mark. Great Smog is history, but foul air still kills (The Observer, 24 November 2002).
  8. ^ Matthew Wills (24 August 2015). "Old Smoke: London's Famous Fog". JSTOR Daily.
  9. ^ "The Great Smog of 1952". Archived from the original on 3 September 2014. Retrieved 12 October 2014.
  10. ^ Sheail, John (1991). Power in Trust: the environmental history of the Central Electricity Generating Board. Oxford: Clarendon. pp. 22, 42–3. ISBN 0-19-854673-4.
  11. ^ a b Mason, Nigel; Hughes, Peter (2001). Introduction to Environmental Physics. CRC Press. pp. 112–13. ISBN 978-0748407651.
  12. ^ "Atmosphere, Climate & Environment Information Programme". 4 December 1952. Archived from the original on 25 February 2009. Retrieved 30 June 2010.
  13. ^ "Met Office Education: Teens – Case Studies – The Great Smog". Archived from the original on 5 June 2011. Retrieved 30 June 2010.
  14. ^ Greater London Authority. 50 Years On: The struggle for air quality in London since the great smog of December 1952.
  15. ^ Nielson, John. "The Killer Fog of '52". NPR. Retrieved 14 December 2013.
  16. ^ "London fog clears after days of chaos". BBC News. Retrieved 7 December 2014.
  17. ^ . The Guardian Retrieved 6 April 2020. Missing or empty |title= (help)
  18. ^ "The Great Smog of 1952". Retrieved 17 August 2008.
  19. ^ "Coal: Nutty slack". Commons Sitting of 16 February 1953.
  20. ^ Davis DL. 2002. When Smoke Ran Like Water. New York:Basic Books.
  21. ^ Peters, Annette ; Döring, Angela ; Wichmann, H-Erich ; Koenig, Wolfgang (1997) 'Increased plasma viscosity during an air pollution episode: a link to mortality?' The Lancet, 1997, Vol. 349 (9065), pp. 1582–87
  22. ^ Hunt, Andrew; Abraham, Jerrold L; Judson, Bret; Berry, Colin L (2003). "Toxicologic and epidemiologic clues from the characterization of the 1952 London smog fine particulate matter in archival autopsy lung tissues". Environmental Health Perspectives. 111 (9): 1209–14. doi:10.1289/ehp.6114. PMC 1241576. PMID 12842775.
  23. ^ Bell ML, Davis D. 2001. Reassessment of the lethal London fog of 1952: novel indicators of acute and chronic consequences of acute exposure to air pollution. Environ Health Perspect 109(suppl 3):389–94.
  24. ^ Camps, Francis E (Ed.) (1976). Gradwohl's Legal Medicine (Bristol: John Wright & Sons Ltd, 3rd ed.) ISBN 0-7236-0310-3. p. 236.
  25. ^ Andrew; Abraham, Jerrold L.; Judson, Bret; Berry, Colin L. (2003). "Toxicologic and Epidemiologic Clues from the Characterization of the 1952 London Smog Fine Particulate Matter in Archival Autopsy Lung Tissues Hunt". Environmental Health Perspectives. 111 (9): 1209–14. doi:10.1289/ehp.6114. PMC 1241576. PMID 12842775.
  26. ^ Stone, R (2002). "Counting the Cost of London's Killer Smog" (PDF). Science. 298 (5601): 2106–2107. doi:10.1126/science.298.5601.2106b. PMID 12481106.
  27. ^ "Choking fog spreads across Britain". BBC News. Retrieved 16 January 2015.
  28. ^ Domonoske, Camila (23 November 2016). "Research On Chinese Haze Helps Crack Mystery of London's Deadly 1952 Fog". NPR. Retrieved 23 November 2016.

Further readingEdit

External linksEdit

The death toll formed an important motivation to modern ecology and it produced a reconsidering of air pollution.