London Smog 1952 Case Study

In the Great Smog of 1952, the city of London was brought to a standstill by a dense blanket of toxic smog that reduced visibility to a few feet. For five cold December days, a heavy fog combined with sulfurous fumes from coal fires, vehicle exhaust and power plants, blocking out the sun and creating a public health disaster. The "Big Smoke" was the worst air pollution crisis in European history, killing an estimated 8,000 to 12,000 people.

The Great Smog Begins

Clear skies dawned over London on December 5, 1952. A wintry cold snap had gripped the British capital for weeks, and as Londoners awoke, coal fireplaces were stoked in homes and businesses across the city to take the chill from the early morning air.

As the day progressed, a veil of fog—not unusual in a city famous for its cool, misty weather—began to enshroud Big Ben, St. Paul’s Cathedral, London Bridge and other city landmarks.

Within a few hours, however, the fog began to turn a sickly shade of yellowish brown as it mixed with thousands of tons of soot pumped into the air by London’s factory smokestacks, chimneys and automobiles. Smoky, diesel-fueled buses had recently replaced the city’s electric tram system, adding to the toxic brew.

Nonetheless, Londoners went about their business with typical British reserve, ignoring the foul air as much as possible. But within a day, it became impossible to ignore the unfolding crisis.

London Fog Becomes London Smog

Fog, combined with smoke to produce smog, was nothing new in London, but this particular “pea souper” quickly thickened into a poisonous stew unlike anything the city had ever experienced.

A high-pressure weather system had stalled over southern England and caused a temperature inversion, in which a layer of warm air high above the surface trapped the stagnant, cold air at ground level.

The temperature inversion prevented London’s sulfurous coal smoke from rising, and with nary a breeze to be found, there was no wind to disperse the soot-laden smog. The noxious, 30-mile-wide air mass, teeming with acrid sulfur particles, reeked like rotten eggs—and it was getting worse every day.

The Big Smoke Settles In

The smog was so dense that residents in some sections of the city were unable to see their feet as they walked. For five days, the Great Smog paralyzed London and crippled all transportation, except for the London Underground train system.

Because of poor visibility, boat traffic on the River Thames came to a halt. Flights were grounded and trains cancelled. Even during the middle of the day, drivers turned on their headlights and hanged their heads out car windows to inch ahead through the thick gloom. Many found the effort futile and simply abandoned their cars.

Conductors holding flashlights walked in front of London’s iconic double-decker buses to guide drivers down city streets. Wheezing pedestrians groped their way around the city’s neighborhoods and tried not to slip on the greasy black ooze that coated sidewalks. By the time they returned home, their faces and nostrils blackened by the air, Londoners resembled coal miners.

Authorities advised parents to keep their children home from school, partly from fear they would get lost in the blinding smog. Looting, burglaries and purse snatchings increased as emboldened criminals easily vanished into the darkness.

Weekend soccer games were cancelled, although Oxford and Cambridge carried on with their annual cross-country competition at Wimbledon Common with the help of track marshals who continually shouted, “This way, this way, Oxford and Cambridge” as runners materialized out of the thick haze.

The smog seeped inside buildings as well. A greasy grime covered exposed surfaces, and movie theaters closed as the yellow haze made it impossible for ticket-holders to see the screen.

Health Effects of the Great Smog

The Great Smog of 1952 was much more than a nuisance. It was lethal, particularly for the elderly, young children and those with respiratory problems. Heavy smokers were especially vulnerable because of their already-impaired lungs, and smoking was common at the time, especially among men.

It wasn’t until undertakers began to run out of coffins and florists out of bouquets that the deadly impact of the Great Smog was realized. Deaths from bronchitis and pneumonia increased more than sevenfold. The death rate in London’s East End increased ninefold.

Initial reports estimated that about 4,000 died prematurely in the immediate aftermath of the smog.

The detrimental effects lingered, however, and death rates remained well above normal into the summer of 1953. Many experts now estimate the Great Smog claimed at least 8,000 lives, and perhaps as many as 12,000.

The effects of the Big Smoke weren’t limited to people: Birds lost in the fog crashed into buildings. Eleven prize heifers brought to Earls Court for the famed Smithfield Show choked to death, and breeders fashioned improvised gas masks for their cattle by soaking grain sacks in whiskey.

After five days of living in a sulfurous hell, the Great Smog finally lifted on December 9, when a brisk wind from the west swept the toxic cloud away from London and out to the North Sea.

Aftermath of the Big Smoke

Initially, the British government was slow to act during the Great Smog. Heavy fog was, after all, a common occurrence in London and there was, according to most reports, no immediate sense of urgency to this smog event.

Following a government investigation, however, Parliament passed the Clean Air Act of 1956, which restricted the burning of coal in urban areas and authorized local councils to set up smoke-free zones. Homeowners received grants to convert from coal to alternative heating systems.

The transition away from coal as the city’s primary heating source toward gas, oil and electricity took years, and during that time deadly fogs periodically occurred, such as one that killed about 750 people in 1962. None of them, however, approached the scale of the 1952 Great Smog.

The Great Smog of 1952

A fog so thick and polluted it left thousands dead wreaked havoc on London in 1952. The smoke-like pollution was so toxic it was even reported to have choked cows to death in the fields. It was so thick it brought road, air and rail transport to a virtual standstill. This was certainly an event to remember, but not the first smog of its kind to hit the capital.

Smog had become a frequent part of London life, but nothing quite compared to the smoke-laden fog that shrouded the capital from Friday 5 December to Tuesday 9 December 1952. While it heavily affected the population of London, causing a huge death toll and inconveniencing millions of people, the people it affected were also partly to blame for the smog.

During the day on 5 December, the fog was not especially dense and generally possessed a dry, smoky character. When nightfall came, however, the fog thickened. Visibility dropped to a few metres. The following day, the sun was too low in the sky to burn the fog away. That night and on the Sunday and Monday nights, the fog again thickened. In many parts of London, it was impossible at night for pedestrians to find their way, even in familiar districts. In The Isle of Dogs area, the fog there was so thick people could not see their feet.

A history of smog

Britain has long been affected by mists and fogs, but these became much more severe after the onset of the Industrial Revolution in the late 1700s. Factories belched gases and huge numbers of particles into the atmosphere, which in themselves could be poisonous. The pollutants in the air, however, could also act as catalysts for fog, as water clings to the tiny particles to create polluted fog, or smog.

When some of the chemicals mix with water and air, they can turn into acid which can cause skin irritations, breathing problems, and even corrode buildings. Smog can be identified easily by its thick, foul-smelling, dirty-yellow or brown characteristics, totally different to the clean white fog in country areas.

There are reports of thick smog, smelling of coal tar, which blanketed London in December 1813. Lasting for several days, people claimed you could not see from one side of the street to the other. A similar fog in December 1873 saw the death rate across London rise 40% above normal. Marked increases in death rate occurred, too, after the notable fogs of January 1880, February 1882, December 1891, December 1892 and November 1948. The worst affected area of London was usually the East End, where the density of factories and homes was greater than almost anywhere else in the capital. The area was also low-lying, making it hard for fog to disperse.

How the smog of 1952 formed

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.

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 warmer 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.

Early on 5 December, in the London area, the sky was clear, winds were light and the air near the ground was moist. Accordingly, conditions were ideal for the formation of radiation fog. The sky was clear, so a net loss of long-wave radiation occurred and the ground cooled. When the moist air came into contact with the ground it cooled to its dew-point temperature and condensation occurred. Beneath the inversion of the anticyclone, the very light wind stirred the saturated air upwards to form a layer of fog 100-200 metres deep. Along with the water droplets of the fog, the atmosphere beneath the inversion contained the smoke from innumerable chimneys in the London area.

During the period of the fog, huge amounts of impurities were released into the atmosphere. On each day during the foggy period, the following pollutants were emitted: 1,000 tonnes of smoke particles, 2,000 tonnes of carbon dioxide, 140 tonnes of hydrochloric acid and 14 tonnes of fluorine compounds. In addition, and perhaps most dangerously, 370 tonnes of sulphur dioxide were converted into 800 tonnes of sulphuric acid.

In pictures

1950s car driving in thick smog

Impacts of the smog

The fog finally cleared on December 9, but it had already taken a heavy toll.

  • About 4,000 people were known to have died as a result of the fog, but it could be many more.
  • Many people suffered from breathing problems
  • Press reports claimed cattle at Smithfield had been asphyxiated by the smog.
  • Travel was disrupted for days

Response to the smog

A series of laws were brought in to avoid a repeat of the situation. This included the Clean Air Acts of 1956 and 1968. These acts banned emissions of black smoke and decreed residents of urban areas and operators of factories must convert to smokeless fuels.

People were given time to adapt to the new rules, however, and fogs continued to be smoky for some time after the Act of 1956 was passed. In 1962, for example, 750 Londoners died as a result of a fog, but nothing on the scale of the 1952 Great Smog has ever occurred again. This kind of smog has now become a thing of the past, thanks partly to pollution legislation and also to modern developments, such as the widespread use of central heating.

Web page reproduced with the kind permission of the Met Office

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