Pea soup fog

Pea soup, or a pea souper, also known as a black fog, killer fog or smog is a very thick and often yellowish, greenish, or blackish fog caused by air pollution that contains soot particulates and the poisonous gas sulfur dioxide. This very thick smog occurs in cities and is derived from the smoke given off by the burning of soft coal for home heating and in industrial processes. Smog of this intensity is often lethal to vulnerable people such as the elderly, the very young and those with respiratory problems. The result of these phenomena was commonly known as a London particular or London fog, which then, in a reversal of the idiom, became the name for a thick pea and ham soup.

From as early as the 1200s, air pollution became increasingly prevalent, and a predominant perception in the thirteenth century was that sea-coal smoke would affect one's health. From the mid-1600s, in UK cities, especially London, the incidence of ill-health was attributed to coal smoke from domestic chimneys and industry combining with the mists and fogs of the Thames Valley.Luke Howard, a pioneer in urban climate studies, published The Climate of London in 1818–20, in which he uses the term 'city fog' and describes the heat island effect which concentrated the accumulation of smog over the city.

In 1880 Francis Albert Rollo Russell, son of the former Prime Minister Lord John Russell, published a leaflet that blamed home hearth, rather than factory, smoke for damaging the city’s important buildings, depriving vegetation of sunlight, and increasing the expense and effort of laundering clothes. Furthermore he charged the ‘perpetually present’ sulphurous smoke with increasing bronchitis and other respiratory diseases. More than 2000 Londoners had ‘literally choked to death’, he wrote, on account of ‘a want of carefulness in preventing smoke in our domestic fires’ which emitted coal smoke from ‘more than a million chimneys’ that when combined with the prolonged fogs of late January and early February 1880, fatally aggravated pre-existing lung conditions and was ‘more fatal than the slaughter of many a great battle’.

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