From Wikipedia, the free encyclopedia
The Great Smog or Big
Smoke[1]
was a severe air
pollution event that affected London in December 1952. A period of cold
weather combined with an anticyclone and windless conditions,
collected airborne pollutants mostly from the use of coal to form a thick layer of smog over the city. It lasted from
Friday 5th to Tuesday 9 December 1952, then quickly dispersed after
a change in the weather.
Although it caused major disruption due to the effect on
visibility, and even penetrated indoor areas, it was not thought to
be a significant event at the time, with London having experienced
many smog events in the past, so called "pea soupers". In the following weeks
however, medical reports estimated that 4,000 had died prematurely
and 100,000 more were made ill due to the smog's effects on the
human respiratory tract. More recent
research suggests that the number of fatalities was considerably
higher at around 12,000.[2]
It is considered the worst air pollution event in the history of the United
Kingdom[3], and
the most significant in terms of its impact on environmental
research, government regulation, and public awareness of the
relationship between air quality and health.[2]
It led to several changes in practices and regulations, including
the Clean
Air Act 1956.
Events
Sources of
Pollution
The weather preceding and during the smog meant that Londoners
had to burn more coal than usual to keep warm. Post-war domestic
coal tended to be of a relatively low-grade, sulphurous variety,
which increased the amount of sulphur dioxide in the smoke
(economic necessity meant that higher quality 'hard' coals tended
to be exported). There were also numerous coal fired power stations
within the Greater London area including Battersea, Bankside, and Kingston upon Thames,
all of which added to the pollution levels. (Research suggests that
additional pollution prevention systems fitted at Battersea may
actually have worsened the air quality, reducing the output of soot
at the cost of increased sulphur dioxide, though this is not
clear). In addition there was pollution and smoke from vehicle
exhausts – particularly from diesel-fuelled buses which had
replaced the recently scrapped electric tram system – and from
other industrial and commercial sources.[4]
Prevailing winds had also blown heavily-polluted air across the English Channel
from industrial areas of Europe.
Weather
On Thursday 4 December 1952, an anticyclone settled over a windless London,
causing a temperature
inversion with very cold, stagnant air trapped under a layer
(or "lid") of warm air. The resultant fog, mixed with chimney
smoke, particulates (e.g. from vehicle exhausts) and other
pollutants (particularly sulphur dioxide)
resulted to form a persistent smog, which blanketed the capital
(the presence of tarry particles of soot gave the smog its
yellow-black colour – hence the nickname "peasouper").[4]
The absence of significant wind prevented its dispersal and allowed
an unprecedented build up of pollutants.
Impact on
London
Although London was accustomed to thick fogs, this one was
denser and longer lasting than any previously seen.[5]
Visibility was reduced to a few yards ("It's like you were blind",
commented one observer)[6],
making driving difficult or impossible. Public transport ground to
a halt – apart from the London Underground – and the
ambulance service stopped running, forcing the sick to make their
own way to hospital.[6] The
smog even seeped indoors, resulting in the cancellation or
abandonment of concerts and film screenings (as visibility fell in
large enclosed spaces, and stage and screens became harder to see
from the seats). Outdoor sports events were also affected.
Health
Impact
Initially, there was no great panic, as London was renowned for
its fog. In the weeks that followed, however, statistics compiled
by medical services found that the fog had killed 4,000 people[7]. Most
of the victims were very young, elderly, or had pre-existing
respiratory problems. Deaths in most cases were due to respiratory
tract infections
from hypoxia, and due to 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 chronic bronchitis.[8]
A total of 12,000 people are believed to have died in the weeks
and months that followed.
Environmental Impact
The death toll formed an important impetus to the modern environmental
movement, and led to a rethinking of air pollution, as the smog had
demonstrated its lethal potential. New regulations were put in
place restricting the use of dirty fuels in industry and banning
black smoke. In the years that followed, various legislation such
as the Clean Air Acts of 1956 and 1968, and
the City of London (Various Powers) Act 1954, greatly restricted
air pollution.
See also
References
- ^ Stegeman, John J.
& Solow, Andrew R. A Look Back at the London Smog of 1952
and the Half Century Since; A Half Century Later: Recollections of
the London Fog (Environmental Health
Perspectives, Dec 2002).
- ^ a
b
"A Retrospective Assessment of
Mortality from the London Smog Episode of 1952: The Role of
Influenza and Pollution". Environ Health
Perspect 112 (1): 6–8. January 2004. doi:10.1289/ehp.6539.
http://www.ehponline.org/members/2003/6539/6539.html.
- ^
McKie, Robin & Townsend, Mark. Great Smog is history, but
foul air still kills (The Observer, 24 Nov
2002).
- ^ a
b
Mason, Nigel; Hughes, Peter; Mc Mllan, Randall. Introduction to
environmental physics (CRC, 2001), pp112-113.
- ^ Greater London
Authority. 50 Years On: The struggle
for air quality in London since the great smog of December
1952, p3.
- ^ a
b
NPR. Killer Fog of '52
(National Public Radio).
- ^
"The Great Smog of 1952".
www.metoffice.gov.uk. http://www.metoffice.gov.uk/education/teens/casestudy_great_smog.html. Retrieved
2008-08-17.
- ^ Camps, Francis E (Ed.)
(1976). Gradwohl's Legal Medicine (Bristol: John Wright
& Sons Ltd, 3rd ed.) ISBN 0 7236 0310 3. p236.
Further
reading
- Bell, Michelle L. and Davis, Devra Lee. Reassessment of the
Lethal London Fog of 1952: Novel Indicators of Acute and Chronic
Consequences of Acute Exposure to Air Pollution ("Environmental Health
Perspectives", June 2001).
- Berridge, Virginia (Ed.). The Big Smoke: Fifty Years After
the 1952 London Smog (University of London, Institute of
Historical Research, 2005)
- Brimblecombe, Peter. The Big Smoke: A History of Air
Pollution in London Since Medieval Times (Routledge Kegan
& Paul, 1987).
- Greater London Authority. 50 Years On: The struggle
for air quality in London since the great smog of December
1952 (Dec 2002).
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