Exactly 68 years ago, in December 1952, London was hit by the largest air pollution event in the history of the United Kingdom.
The Great Smog is the name given to the thick blanket of dense and toxic fog that covered the city of London between 5 and 9 December 1952. From a social point of view this catastrophe caused about 4,000 deaths and thousands of thousands of sick people, from the scientific point of view it represented a curious case of anomaly that gave the possibility to advance useful studies throughout the evolution in environmental safety.
At the turn of the nineteenth and twentieth centuries, London was the scene of great industrial progress: already famous for the fog banks that characterized its image, the growing industrialization and urbanization, with the uncontrolled controlled derivatives of the factories and chimneys of the areas, it constitutes the suitable field for the formation of the phenomenon called smog.
The harsh temperatures that hit England during the first days of December prompted citizens to increase their consumption of coal to heat their families. Coal is not intended for export and consumption in the London regions was a low quality product, rich in sulfur.
The exponential growth of the fumes emitted through the use of coal, both from domestic chimneys and from industrial chimneys, encountered a meteorological situation that aggravated the situation. In fact, between 3 and 4 December 1952, the Azores anticyclone moved its zone of influence over the North Atlantic, causing a thermal inversion over London.
What has come to create, therefore, the production of a dense layer of cold air blocked by a layer of upper hot air. In this way, no ventilation is possible and when the moist air has started to come into contact with the ground, taken through a condensation process.
The sky over London remained dark gray for four long days, due to the continuous combustion of coal and the inability to ventilate its presence. The data of the toxic substances emitted in these days are frightening: from 1,000 tonnes of smoke to 800 of sulfuric acid.
The Great Smog will then be remembered as a tragic moment in the history of the English capital and as a warning against the excess production of toxic fumes in the cities.