The Great Smog
By Devra Davis; Published in History Today Volume 52 Issue 12 December 2002
(This article has been altered to allow for clarity and brevity.)
From December 1952 to March 1953 in Greater London 12,000 residents more than usual perished in
what was modern London’s most massive civilian disaster. Smoke from a million chimneys ran like water
and pumped clotted, coal-fumes into cooler stilled air. Unable to disperse upwards through the heavier
chillier air, hot, smoky fumes fell to the ground and did not visibly diminish for a solid week.
During the unprecedented 1952 smog, the sun remained unseen. Dark days became murky shadowed
nights. Because more people lived closer together in London at that time than in any other modern city,
the city’s residents suffered a colossal health toll.
In the thirteenth century, Londoners began to burn coal as a way to heat their homes. Coal lasted longer
and burned hotter than wood. But not all were enthralled with its smoke. Queen Eleanor, fleeing the
fumes created by heavy use of sea-coale in Nottingham Castle in 1257, issued one of many fruitless royal
bans on coal burning. By the fifteenth century, London’s skies were regularly blackened with coal smoke.
Many residents blamed the region’s foggy weather for the persistent gray air.
The debate about whether coal smoke affected human health effectively ended the winter of 1952-53 in
London. On December 8th, cool air from across the English Channel settled over the Thames Valley and
did not move. Within a week more than 3,000 deaths than usual had occurred. The medical analysist
David Bates, then a young physician experienced in wartime medicine, recalls that officials could not
imagine that the environment could produce more civilian casualties in London than any single incident
of the war. However, the sheer (total) scale of this disaster could not be ignored. In one week alone
4,703 people died, compared with 1,852 during the same week the previous year. Bates recounts the
reluctance of officials to accept that so many people had suddenly dropped dead merely from breathing
dirty air.
Eager to put off demands that measures be taken to reduce use of dirtier coal, and focus on the nation’s
grim economic realities, the British Government sprang into inaction. But officials understood the need
for it to look like the government was doing something in the face of this massive catastrophe. They
authorized the issuance of smog masks, which were known to be useless. And in the ususal government
tradition, officials found it easier to set up a committee to study the problem, rather than come up with
ways to keep lethal smog from recurring. By 1954, the committee report noted that deaths and illnesses
remained higher than usual until the end of February 1953. By 1956 major legislation to require
reductions in coal burning became the law of the land.
Today the public faces newer challenges. Just as the impact of the London smog did not end in a single
week but extended over several months, regular exposure to much lower levels of soiled air today
produces a broad array of human health problems, including earlier deaths in the aged, the ill and the
young, fewer births, more birth defects, and more health problems in children. Yet, in truth,
environmental contamination never appears on anyone’s death certificate, and is seldom thought of as
a contribution to chronic illness.
The Great Smog of ’52: Environmental Disasters in History
BY Bonnie Denmark; December 3, 2014
(This article has been altered to allow for clarity and brevity.)
Fog as thick as pea soup is nothing new to Londoners. But on December 5, 1952, a dense, grimy cloud of
fog descended on London, immobilizing the city and causing more than 3,000 additional deaths over a
five-day period with an additional 8,000 deaths in the aftermath.
The intense pollution event known as The Great Smog resulted from a perfect storm of unusually cold
weather along with high atmospheric pressure that led to thermal inversion, so the ground temperature
was lower than that of the air above. On that nearly windless day, a cap of warmer air trapped smoke
from chimneys and smokestacks in a cold layer of air near the surface. At night, the layer of smog
thickened and took on a sulfurous stink since the low grade domestic coal available in the years
following World War II produced more sulfur dioxide than the higher quality coal previously used.
To make the problem worse, a mist formed in this sheet of cool air. Water droplets collected on
particles of soot and tar. Inside the droplets of water (H2O), sulfur dioxide (SO2) reacted to form sulfuric
acid (H2SO4), creating “acid fog.” Particles of tar gave the smog a yellow-black color characteristic of a
“peasouper.” Ordinarily, the morning sun would have evaporated the mist, but on the morning of
December 6, the sun could not penetrate the thick fog so it continued to blanket the city. The lack of
wind and the warmer cap of air over the cold layer below kept the pollution in place as cold
temperatures caused Londoners to burn even more coal to stay warm. Over the next two nights, the fog
thickened. Soot blackened everything, and it was difficult to breathe.
When The Great Smog first settled on London, it did not raise alarm. For Londoners, smog was part of
city life. Burning coal had kept homes warm and factories operating for centuries. In Bleak House (1852),
Charles Dickens describes “fog down the river, where it rolls defiled [tarnished, made dirty] among the
tiers of shipping and the waterside pollutions of a great city.” At the turn of the century, Claude Monet
visited London specifically to observe the effects of the smog on sunlight, which he captured in a wellknown piece of art work, The Sun Shining through the Fog.
It was only when undertakers started running out of coffins that the city realized the most serious
effects. On December 9, a wind came and blew the fog away, but the episode caused an estimated
12,000 deaths during and after the fog. Many who died were the elderly, the very young, and the ill.
Many others developed lung conditions after the fog. According the UK National Weather Service, the
following pollutants were released into the air daily during The Great Smog:
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1,000 tonnes (= metric tons) of smoke particles
2,000 tonnes of carbon dioxide
140 tonnes of hydrochloric acid
14 tonnes of fluorine compounds
370 tonnes of sulfur dioxide, which was converted into 800 tonnes of sulfuric acid
The killer fog sparked a critical reevaluation of the causes of air pollution in London. For the first time,
air pollution was widely recognized as an imminent health threat in the city. The tragedy led to the Clean
Air Acts of 1956 and 1968, targeting coal burning in homes and factories, as well as future innovations to
reduce pollution.