Great Smog of London

Great Smog of London

Nelson's Column during the Great Smog of 1952
Date	5 to 9 December 1952
Location	London, England, United Kingdom
12,000 Dead
200,000 Injured

The Great Smog of London, or Great Smog of 1952 sometimes called the Big Smoke, was a severe air-pollution event that affected the British capital of London in December 1952. A period of cold weather, combined with an anticyclone and windless conditions, collected airborne pollutants – mostly arising from the use of coal – to form a thick layer of smog over the city. It lasted from Friday, 5 December to Tuesday, 9 December 1952 and then dispersed quickly when the weather changed.

It caused major disruption by reducing visibility and even penetrating indoor areas, far more severe than previous smog events experienced in the past, called "pea-soupers". Government medical reports in the following weeks, however, estimated that up until 8 December, 4,000 people had died as a direct result of the smog and 100,000 more were made ill by the smog's effects on the human respiratory tract. More recent research suggests that the total number of fatalities was considerably greater, about 12,000.

London had suffered since the 1200s from poor air quality, which worsened in the 1600s, but the Great Smog is known to be the worst air-pollution event in the history of the United Kingdom, and the most significant in terms of its effect on environmental research, government regulation, and public awareness of the relationship between air quality and health. It led to several changes in practices and regulations, including the Clean Air Act 1956.

The cold weather preceding and during the Great Smog led Londoners to burn more coal than usual to keep warm. Post-war domestic coal tended to be of a relatively low-grade, sulphurous variety (economic necessity meant that better-quality "hard" coals tended to be exported), which increased the amount of sulphur dioxide in the smoke. There were also numerous coal-fired power stations in the Greater London area, including Fulham, Battersea, Bankside, Greenwich and Kingston upon Thames, all of which added to the pollution. According to the UK's Met Office, the following pollutants were emitted each day during the smoggy period: 1,000 tonnes of smoke particles, 140 tonnes of hydrochloric acid, 14 tonnes of fluorine compounds, and 370 tonnes of sulphur dioxide which may have been converted to 800 tonnes of sulphuric acid.