The document summarizes the Great Smog of London in 1952, one of the worst air pollution events in UK history. Dense fog caused by coal burning for heat during cold weather was trapped over the city by an atmospheric temperature inversion from December 5-9. The smog led to increased mortality, with estimates of over 4,000 additional deaths from respiratory illness. The event spurred the passage of the Clean Air Act in 1956, marking a turning point in UK environmental policy.

1. Great Smog of London (1952)
DONE BY:- AAKASH TOMAR

2. INDEX
⊡ INTRODUCTION
⊡ PEA-SOUPER
⊡ SOURCES
⊡ COALFACTOR
⊡ TEMPERATUREINVERSION
⊡ EFFECTSONLONDON
⊡ HEALTHEFFECTS
⊡ ENVIRONMENTALIMPACT
⊡ CLEANAIRACT1956
⊡ INPOPULARFICTION
⊡ LONDONFOG(1956)

3. INTRODUCTION
⊡ The Great Smog of London(1952), was a severe air pollution
event that affected London, England, in December of 1952.
⊡ It lasted from 5th to 9th of December 1952 and then dispersed
quickly when the weather change. This disaster resulted in
thousands of deaths.
⊡ Visibility was so impaired in some parts of London that
pedestrians were unable to see their own feet.
⊡ Due to its severity, road ,air and rail transport were brought to a
virtual standstill.
⊡ It was caused by a combination of industrial pollution and high-
pressure weather conditions

4. • The Great Smog is thought to be the worst air pollution event in
the history of the United Kingdom.
• The Clean Air Act was passed four years later, which marked a
turning point in the history of environmentalism.

5. PEA-SOUPER
⊡ The phenomenon of “London fog”
long predated the crisis of the early
1950s.
⊡ Known as “pea-soupers” for their
dense, yellow appearance, such all-
encompassing fogs had became a
hallmark of London by the 19th
century.
⊡ polluted fog was an issue in London
as early as the 13th century, due to
the burning of coal, and the situation
only worsened as the city continued
to expand.

6. SOURCES
⊡ An anticyclone is a weather phenomenon defined
as a large-scale circulation of winds around a
central region of high atmospheric pressure,
clockwise in the Northern Hemisphere and
counterclockwise in the Southern Hemisphere as
viewed from above (opposite to a cyclone).
 Effects of surface-based anticyclones include clearing
skies as well as cooler, drier air. Fog can also form
overnight within a region of higher pressure.
 The weather in November and early December 1952
had been very cold, with heavy snowfalls across the
region.
 To keep warm, the people of London were burning
large quantities of coal in their homes. Smoke was
pouring from the chimneys of their houses.

7. COAL FACTOR
• While better-quality "hard" coals (such as anthracite) tended
to be exported to pay off World War II debts, post-war
domestic coal tended to be of a relatively low-grade,
sulphurous variety (similar to lignite) 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 King
ston upon Thames, all of which added to the pollution.

8. TEMPERATURE
INVERSION
• Under normal conditions, smoke would rise into
the atmosphere and disperse, but an
anticyclone was hanging over the region.
• This pushes air downwards, warming it as it
descends. This creates an inversion, where air
close to the ground is cooler than the air higher
above it. So when the warm smoke comes out
of the chimney, it is trapped.
• The inversion of 1952 also trapped particles
and gases emitted from factory chimneys in the
London area, along with pollution which the
winds from the east had brought from industrial
areas on the continent.

9. • London was accustomed to heavy fogs, this one
was denser and longer-lasting than any previous
fog.
• Public transport ceased, apart from the London
underground.
• The smog seeped indoors, resulting in
cancellation of concerts and film screenings as
visibility decreased in large enclosed
spaces. Outdoor sports events were also
cancelled.
• 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.
• 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.
EFFECTS ON LONDON

10. •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.
•Marcus Lipton suggested in the House of Commons that the fog had caused 6,000
deaths and 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
finalized, 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.
•Research published in 2004 suggests that the number of fatalities was considerably
greater than contemporary estimates, at about 12,000.
HEALTH EFFECTS

11. •Environmental legislation since 1952, such as the City of London 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.
ENVIRONMENTAL IMPACT

12. THE CLEAN AIR ACT 1956
⊡ The Clean Air Act 1956 was an Act of the Parliament of the United Kingdom enacted
principally in response to London's Great Smog of 1952.
⊡ It was sponsored by the Ministry of Housing and Local Government in England and the
Department of Health for Scotland, and was in effect until 1993.
⊡ The Act introduced a number of measures to reduce air pollution.
⊡ Primary among them was mandated movement toward smokeless fuels, especially in high-
population ‘smoke control areas’ to reduce smoke pollution and sulphur dioxide from
household fires.
⊡ The Act also included measures that reduced the emission of gases, grit, and dust from
chimneys and smoke-stacks.
⊡ The Act was a significant milestone in the development of a legal framework to protect the
environment.
⊡ The Act was repealed by the Clean Air Act 1993.

13.  The CAA focused on
controlling domestic and
industrial emissions. The
main sections under the CAA
of 1956 included;
• Dark smoke
• Smoke from furnaces
• Grit and dust from furnaces
• Smoke control areas
• Smoke nuisances

15. IN POPULAR FICTION
⊡ The Great Smog is the central event of season
1, episode 4 of Netflix's show The Crown. The
representation of the air pollution was regarded
as reasonably accurate by critics, although the
political importance and the chaos in the
hospitals were thought to have been greatly
exaggerated.
⊡ The Boris Starling novel Visibility is set in the
1952 smog event.

16. LONDON FOG (1956)
 There was some fog in the London area on January 3, 1956. This became thick on the morning
of January 4 and persisted until the morning of January 6, when it began to disperse.
 In London the fog was thick enough to cause very severe disruption of traffic, particularly on
the evening of January 5
 Newspapers carried headlines about ‘killer smog’ described the widespread investigations that
were being conducted during the fog into the degree of atmospheric pollution that was taking
place, and reminded readers that the previous severe London fog, in December, 1952, had
caused several thousand deaths in the London area.
 While there was, as usual, some reduction in temperature during the fog period this was not
severe, and was probably insufficient, by itself, to cause much additional mortality. There was
no epidemic influenza prevalent in London at the time.
 It may be concluded, therefore, that the majority of the additional deaths, amounting to
almost 1,000, in the Greater London area between January 4 and 14 were caused by the fog.

17. AGE DISTRIBUTION OF DEATHS
The increase was relatively
greatest (67%) among
newborn children, but in
numbers of deaths by far the
greatest increase was among
elderly persons-an increase
of 358 deaths (30%),
compared with a total
increase (all ages) of 454.

18. CAUSES OF DEATH:
Bronchitis was principally involved,
and registered deaths from this cause
rose from 169 to 377, an increase of
123%, between the last two weeks of
December and the first two weeks of
January. Between the period
December 25 to January 3 and the
period January 4 to 13 bronchitis
deaths occurring increased from 155
to 301, or by 94%.

19. CONCLUSION
 In the face of the apparent infrequency of such incidents
throughout much of the nineteenth and the first half of the
twentieth century, the fact that three incidents have
occurred during the past eight winters is disquieting.
 It suggests the possibility either that the atmospheric
pollution associated with London fogs has recently become
more toxic, particularly to the very young, the infirm, and
the elderly, or that there has been an increase in the
number of persons who are specially vulnerable to its
effects.
 The 4,000 deaths in December, 1952, made a deep
impression on the public imagination. These further 1,000
deaths last January are a stern reminder that this major
public health problem has not yet been solved.

20. REFERENCE
⊡ https://en.wikipedia.org/wiki/Great_Smog_of_London
⊡ https://www.slideshare.net/jagniyant/great-smog-of-
london1
⊡ https://www.britannica.com/event/Great-Smog-of-London
⊡ https://www.theverge.com/2017/12/16/16778604/london-
great-smog-1952-death-in-the-air-pollution-book-review-
john-reginald-christie
⊡ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1979260/pd
f/brmedj03200-0030.pdf

21. THANK YOU