On this day in (engineering) history…
The Great London Smog, December 5, 1952
Step outdoors on the evening of December 5, 1952 and you will be met by a fog; a sickly, yellow brown fog so thick that in places, such as east London’s Isle of Dogs, people couldn’t see their feet. Over the coming days, it is so dark, you spot policemen using flares to see around them and provide a point of reference for traffic and pedestrians. Soon, you feel your eyes, throat and lungs develop a burning sensation. You start coughing and struggle to breathe. The next day is the same, and the next. The smog will remain stuck over large swathes of London for the next four days.
The winter of 1952 was particularly cold. This day opened with a chill bite in the air, clear skies, light winds and moist air at ground level. Residents lit fires to warm up their homes. Offices followed suit. Steam trains, cars, buses, and trucks kept people and goods moving across the capital. It didn’t help that, after the end of the Second World War, the coal used in peoples’ fireplaces was a cheap, low quality, sulphur-rich alternative to the harder, better-quality coal used in the past - now being exported to help lift the country out of near bankruptcy.
As the pollutants this produced began to rise into the atmosphere, an anticyclone (high pressure) settled over London. When the ground cooled to its dew point, condensation formed, while the light winds lifted the moist air higher to produce a fog up to 200 metres thick. This, combined with smoke from industry and those coal fires mixed to produce a classic London ‘pea souper’ smog, although far nastier than usual.
Over each day the fog persisted, the city belched out 2,000 tonnes of carbon dioxide, 140 tonnes of hydrochloric acid, 1400 tonnes of fluorine compounds and 370 tonnes of sulphur dioxide turned into 800 tonnes of sulphuric acid. All this over an area stretching 40 miles (64 kilometres) across London, from Hounslow in the west to Havering in the north-east.
Put another way, from December 4 and 8, 1952, it was estimated particulate matter in the smoke reached 14mg/m3, some 56 times the normal levels for the time. Sulphur dioxide levels grew 7 times, reaching approximately 700ppb.
These smogs were not unknown in London life. They go back as far as the thirteenth century, prompted by the use of coal for heating. Things became so bad over the centuries, that James I passed (ineffective) legislation to restrict the burning of coal. Things took a turn for the worse in the eighteenth century when the country began to industrialise. By the end of the nineteenth century, London’s air was in crisis, with furnaces and a rapidly growing population (one million in 1801 became 6 million by the end of the century) enjoying the comforts of a home fire and pouring industrial quantities of pollutants into the atmosphere.
A thick smog was noticed in December 1813, reappearing in 1873, 1880, 1882, 1891, 1892 and in 1948. The hardest hit area tended to be the East End, crammed with dense housing and factories. It was harder for the fog here to move because the ground is low lying.
During this fog, transport above ground became impossible. Flights were cancelled, ambulances were stopped, people drove their cars with headlights on and heads out of the windows to see where they were going. Or they abandoned their cars in the street. Buses were led through the darkness by bus conductors and river traffic disappeared.
Hospitals became jammed with patients suffering with breathing difficulties of varying severity, and remained so for months.
In theatres and cinemas, performances were called off when stage and screen became veiled in smog, despite them being indoors. There are reports of live cattle being asphyxiated in Smithfield market and in fields.
On December 9, a brisk westerly wind blew the toxic cloud out over the North Sea. Londoners were left with a blackened, sticky mess inside and outside buildings, public and private alike. Otherwise, London resumed its day-to-day life and people got on with life. It was only in the following months as statistics were released, and death notices published, the fearful toll it took on Londoners became clear.
Tobacco smoking of one form or another was a common factor in society of the time, especially among men. Even so, it is believed up to 4,000 people lost their lives during those choking December days, rising to 12,000 in the subsequent months. In London’s East End, excess deaths increased sevenfold. Up to 100,000 were hospitalised by the smog.
There was a Parliamentary inquiry, which eventually resulted in the Clean Air Act of 1956. This set limits on the burning of coal in urban areas. It allowed local councils to set up smoke-free zones, while homeowners were given grants to fund the change from coal to different forms of heating.
The era of coal heating in London was ended by the Act, but making the change took time. Another London fog arrived in 1962. Even though this is not classified as a severe event, it still killed 750 people.
Another Clean Air Act followed in 1968.
Now, there is once again controversy about London’s air. This time, the pollution can still be measured but is invisible, a factor that perhaps makes it harder to resolve.
Until relatively recently, we used to think of ‘progress’ and the future as cleaner, being better organised, with better technology than contemporary society. But so often, this isn’t the case.
Why do progress and environmental degredation and pollution always appear to follow each other?
Why not join the discussion and tell us what you think of the issues raised in this blog!
Stephen Phillips is an IET Content Producer, with passions for history, engineering, tech and the sciences.