Smog of London, or Great
Smog of 1952 was a severe
air-pollution event that affected the British capital of
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 then dispersed quickly when the weather
It caused major disruption by reducing visibility and even penetrating
indoor areas, far more severe 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. More
recent research suggests that the total number of fatalities was
considerably greater; about 8,000 more died in the following months as
a result of the event.
London had suffered since the 13th century from poor air quality,
which worsened in the 1600s, but the Great
Smog is known to be
the worst air-pollution event in the history of the United Kingdom,
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. It led to several
changes in practices and regulations, including the Clean Air Act
1.1 Sources of pollution
2.1 Effect on London
2.2 Health effects
2.3 Environmental impact
4 In popular culture
5 See also
7 Further reading
8 External links
Sources of pollution
Battersea Power Station, pictured in 2012
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
(economic necessity meant that better-quality "hard" coals tended to
be exported), which increased the amount of sulphur dioxide in the
smoke. There were also numerous coal-fired power stations in the
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 sulphur dioxide which may have been
converted to 800 tonnes of sulphuric acid.
Research suggests that additional pollution-prevention systems fitted
at Battersea may have worsened the air quality, reducing the output of
soot at the cost of increased sulphur dioxide, though this is not
certain. 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 – and from other industrial and commercial sources.
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. 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". The
absence of significant wind prevented its dispersal and allowed an
unprecedented accumulation of pollutants.
Effect on London
London was accustomed to heavy fogs, this one was denser and
longer-lasting than any previous fog. Visibility was reduced to a
few metres ("It's like you were blind") making driving difficult
Public transport ceased, apart from the
London Underground, and the
ambulance service stopped, forcing users to transport themselves to
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. Outdoor sports events were
also cancelled.
In the inner
London suburbs and away from town centres, 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 metre 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 kerbs. 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.
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.
There was no panic, as
London was renowned for its fog. In the weeks
that ensued, however, statistics compiled by medical services found
that the fog had killed 4,000 people. Most of the victims
were very young or elderly, or had pre-existing respiratory problems.
In February 1953, Lieutenant-Colonel 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.
Mortality remained elevated for months after the fog. A preliminary
report, never finalised, blamed those deaths on an influenza
epidemic. Emerging evidence revealed that only a fraction of the
deaths could be from influenza. 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. The lung infections were
mainly bronchopneumonia or acute purulent bronchitis superimposed upon
More recent research suggests that the number of fatalities was
considerably greater than contemporary estimates, at about
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
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 favour 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
Atmospheric scientists at Texas A&M University investigating the
haze of polluted air in
Beijing realized 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 sulfuric acid."
Even though research findings point in this direction, the two events
are not identical. In China, the combination of nitrogen dioxide and
sulfur dioxide, both produced by burning coal, with a humid
atmosphere, created sulfates while building up acidic conditions that,
left unchanged, would have stalled the reaction. However, ammonia from
agricultural activity neutralized the acid allowing sulfate production
to continue.
It is theorised that in 1952 in London, the nitrogen dioxide and
sulfur dioxide combined with fog rather than humidity; larger droplets
of water diluted the acid products, allowing more sulfate production
as sulfuric acid. Sunrise burned off the fog, leaving concentrated
acid droplets that killed citizens.
In popular culture
Smog served as the basis of an episode titled "Forog" of The
Goon Show (series 5, episode 13), which aired on 21 December 1954.
The event was a central plot line in the episode "An Act of God"
(season 1, episode 4) of the
Netflix series The Crown (released in
It also features prominently in Dominion, an alternate history novel
by C. J. Sansom.
1930 Meuse Valley fog
1939 St. Louis smog
1948 Donora smog
1966 New York City smog
2013 Harbin smog
2013 Shanghai smog
London low emission zone
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^ McKie, Robin & Townsend, Mark. Great
Smog is history, but foul
air still kills (The Observer, 24 November 2002).
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London Authority. 50 Years On: The struggle for air quality
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^ Davis DL. 2002. When Smoke Ran Like Water. New York:Basic Books.
^ Peters, Annette ; Döring, Angela ; Wichmann,
H-Erich ; Koenig, Wolfgang (1997) 'Increased plasma viscosity
during an air pollution episode: a link to mortality?' The Lancet,
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^ Hunt, Andrew; Abraham, Jerrold L; Judson, Bret; Berry, Colin L
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exposure to air pollution. Environ Health Perspect 109(suppl
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^ Andrew; Abraham, Jerrold L.; Judson, Bret; Berry, Colin L. (2003).
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Smog Fine Particulate Matter in Archival Autopsy Lung
Tissues Hunt". Environmental Health Perspectives. 111 (9): 1209–14.
^ Stone, R (2002). "Counting the Cost of London's Killer Smog".
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^ "Choking fog spreads across Britain". BBC News. Retrieved 16 January
^ Domonoske, Camila (2016-11-23). "Research On Chinese Haze Helps
Crack Mystery of London's Deadly 1952 Fog". NPR. Retrieved 23 November
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^ Samuelson, Kate (4 November 2016). "Everything to Know About the
Smog of 1952, as Seen on The Crown". Time.
Bates, David V. "Recollections of the
London Fog." Environmental
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Bell, Michelle L.; Davis, Devra Lee (June 2001). "Reassessment of the
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Berridge, Virginia (Ed.). The Big Smoke: Fifty Years After the 1952
Smog (University of London, Institute of Historical Research,
Brimblecombe, Peter. The Big Smoke: A History of Air Pollution in
London Since Medieval Times (Routledge Kegan & Paul, 1987)
Davis, Devra L. "A look back at the
London smog of 1952 and the half
century since." Environmental health perspectives 110.12 (2002): A734.
Davis, Devra L. "The Great Smog" History Today (Dec 2002) Vol. 52,
Dawson, Kate Winkler. Death in the Air: The True Story of a Serial
Killer, the Great
London Smog, and the Strangling of a City (Hachette
Book Group, 2017)
London Authority. 50 Years On: The struggle for air quality in
London since the great smog of December 1952 (December 2002)
Thorsheim, Peter. Inventing Pollution: Coal, Smoke, and Culture in
Britain Since 1800 (Ohio University Press, 2006)
Edinburgh University: The
Smog Disaster of 1952
BBC News: Days of toxic darkness
London fog clears after days of chaos (BBC News, 9 December
Persistent sulfate formation from
London Fog to Chinese haze PNAS
Scientists finally know what caused a mysterious fog to kill 12,000
London in 1952
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