London's best coal went abroad, leaving the sulphurous dregs to choke the city
For five days in December 1952 a yellow-green smog so thick it seeped into cinemas settled over London. Officials counted about 4,000 deaths; later research puts the toll nearer 12,000. Part of the blame lay with post-war economics: good coal was exported to pay war debts, and Londoners burned low-grade nutty slack.
London's air had been foul for centuries. In 1661 the diarist John Evelyn wrote Fumifugium, the first book devoted to air pollution, complaining about the capital's smoke. But nothing matched December 1952. A bitter cold spell had households burning far more coal than normal, and the domestic supply was a cheap sulphur-rich grade, because harder coals such as anthracite were being sold overseas. Coal-fired power stations at Battersea, Bankside and elsewhere added their share, as did steam trains and the diesel buses that had just replaced trams. Even a new flue-washing system at Battersea backfired, cooling its exhaust so that the fumes sank instead of rising.
On 4 December an anticyclone parked over a windless city and trapped cold air beneath a warmer layer. Fog mixed with soot and sulphur dioxide, and tarry particles tinted it the colour that gave such fogs the name pea-souper. By Sunday 7 December visibility had dropped to about a foot. Only the Underground kept running; concerts and film shows were abandoned because audiences could not see the stage, and pedestrians shuffled along feeling for kerbs. The smog lifted quickly once the weather changed on 9 December.
The human cost emerged slowly. Early reports suggested up to 4,000 deaths, mostly among the very young, the elderly and people with heart or lung disease. Elevated death rates lasted into early 1953 and were at first blamed on influenza, but E. T. Wilkins, the government's leading pollution scientist, calculated about 8,000 extra deaths, making 12,000 in all; research in 2004 reached a similar figure. People who were babies or still in the womb at the time were later found to have lower intelligence and poorer lungs.
The disaster reshaped policy. The Clean Air Act of 1956, followed by another in 1968, and grants to swap open coal fires for gas or smokeless coke steadily cleaned the air, although another smog struck in December 1962.
Source: Great Smog of London
