Great London Smog
During the 19th century, the increase in industrialisation in the major cities of Britain gave rise to a dramatic increase in air pollution. Throughout the autumn months, during periods of calm, smoke particles from industrial plumes would mix with fog giving it a yellow-black colour. Such smogs, as they became known, often settled over cities for many days. Wind speeds would be low at these times causing the smog to stagnate, with pollution levels increasing near ground level. London became quite famous for its smogs, and many visitors came to see the capital in the fog.
During the first part of the 20th century, tighter industrial controls and the declining importance of coal as a domestic fuel led to a reduction in smog pollution in urban areas. However, on December 4th 1952, an anticyclone settled over London. The wind dropped and the air grew damp; a thick fog began to form. The Great London Smog lasted for five days and led to around four thousand more deaths than usual. The deaths were attributed to the dramatic increase in air pollution during the period, with levels of sulphur dioxide increasing 7-fold, and levels of smoke increasing 3-fold. The peak in the number of deaths coincided with the peak in both smoke and sulphur dioxide pollution levels.
In response to the Great London Smog, the Government passed its first Clean Air Act in 1956, which aimed to control domestic sources of smoke pollution by introducing smokeless zones. In addition, the introduction of cleaner coals led to a reduction in sulphur dioxide pollution.