Pea soup fog
Pea soup, or a pea souper, also known as a black fog or killer fog, is a very thick and often yellowish, greenish, or blackish smog 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.
Pea soup fog was once prevalent in UK cities, especially London, where the coal smoke from millions of chimneys combined with the mists and fogs of the Thames valley. The result 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.
King Edward I of England banned the burning of sea-coal by proclamation in London in 1272, after its smoke became a problem. By the 17th century London's pollution had become a serious problem, still due, in particular, to the burning of cheap, readily available sea coal. John Evelyn, advisor to King Charles II, defined the problem in his pamphlet, “Fumifugium: Or, the Inconvenience of the Aer, and Smoake of London Dissipated” published in 1661, blaming coal, a “subterrany fuel” that had “a kind of virulent or arsenical vapour arising from it” for killing many. He proposed the relocation of industry out of the city and the planting of massive gardens of “odiferous flowers” to “tinge the air” and thus mask the pollution.
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.
Reference to the sources of smog, along with the earliest use of 'pea-soup' as a descriptor, is found in a report by John Sartain published in 1820 on life as a young artist, recounting what it was like to; "...slink home through a fog as thick and as yellow as the pea-soup of the eating house; return to your painting room [...] having opened your window at going out, to find the stink of the paint rendered worse, if possible, by the entrance of the fog, which, being a compound from the effusions of gas pipes, tan yards, chimneys, dyers, blanket scourers, breweries, sugar bakers, and soap boilers, may easily be imagined not to improve the smell of a painting room!" 
An 1871 New York Times article refers to "London, particularly, where the population are periodically submerged in a fog of the consistency of pea soup..." The fogs caused large numbers of deaths from respiratory problems.
Clean Air Act
The worst recorded instance was the Great Smog of 1952, when 4,000 additional deaths were reported in the city over a couple of days, leading to the passage of the Clean Air Act 1956, which banned the use of coal for domestic fires in urban areas. The overall death toll from that incident is now believed to be around 12,000.
In Chapter XXXIV of Thomas Love Peacock's Melincourt (1817), the Reverend Mr. Portpipe tells his visitors that he has "good ale and a few bottles of London Particular." A footnote by David Garnett, editor of the 1948 edition, explains that this is "a Madeira wine imported for the London market and hence, from its colour, a London fog."
A first mention in literature of 'pea-soup' as a description of fog appears in 1834; 'On the occasion of which now I am to speak, there was any thing but gaiety and mirth. It was a wretched morning; there fell a mizzling rain through the peas-soup atmosphere of London, which chilled every living thing, while a sort of smoky misty, foggy vapour, hovering over the ground, made "darkness only visible"', from Theodore Edward Hook (1834). Maxwell a novel. London R. Bentley, p.10
A second appears in 1839; "It was not, therefore, until he had left Italy, that Lord Cheveley felt his utter wretchedness and desolation: and London in December was not calculated to lessen it, as it only presents a pea-soup fog, which renders the necessary and natural process of respiration, almost what Dr. Johnson's idea of fine music ought to be, impossible!", in Lytton, Rosina Bulwer Lytton Baroness (1839). Chevely ; or, The man of honour. E. Bull, London, Volume 2, page 106.
In Chapter 3 of Charles Dickens's Bleak House (1852), when Esther arrives in London, she asks of the person meeting her "whether there was a great fire anywhere? For the streets were so full of dense brown smoke that scarcely anything was to be seen. 'O, dear no, miss,' he said. 'This is a London particular.' I had never heard of such a thing. 'A fog, miss,' said the young gentleman."
The London satirical journal 'Punch' (1860) outlines some venture capital schemes; "Besides a plan just set for for making champagne out of cucumbers, a scheme has been devised for the extraction of pea-soup from London fog. When the foreigner remembers that our fogs are now so frequent that the clear blue sky in England is never clearly seen, he may form a faint conception of the work which is cut out for this Company of Soup Makers. The fog will daily furnish a lot of raw material, which English ingenuity will soon cook into a soup." Various & Lemon, Mark [Editor] 'Facts for Foreigners', Punch, or the London Charivari, Volume XXXVIII, February 18, 1860. p.71
The Arthur Conan Doyle Sherlock Holmes stories describe London fogs, but contrary to popular impression the phrase "pea-soup" is not used; A Study in Scarlet (1887) mentions that "a dun-coloured veil hung over the house-tops."; The Adventure of the Bruce-Partington Plans (1912) describes "a dense yellow fog" that has settled down over London, and later notes "a greasy, heavy brown swirl still drifting past us and condensing in oily drops on the windowpane"; while in The Sign of Four (1890), Holmes soliliquises; "What else is there to live for? Stand at the window here. Was ever such a dreary, dismal, unprofitable world? See how the yellow fog swirls down the street and drifts across the dun-coloured houses.", and, later; "...the day had been a dreary one, and a dense drizzly fog lay low upon the great city. Mud-coloured clouds hung over the muddy streets."
In the phrase "pea-soup fog," the implied comparison may have been to yellow pea soup: "...the yellow fog hung so thick and heavy in the streets of London that the lamps were lighted" (Frances Hodgson Burnett, A Little Princess, 1892); "The yellow fog that rubs its back upon the window-panes," (T. S. Eliot, The Love Song of J. Alfred Prufrock, 1917); "London had been reeking in a green-yellow fog" (Winston Churchill, A Traveller in War-Time, 1918); "the brown fog of a winter dawn" (T. S. Eliot, The Waste Land, 1922); "a faint yellow fog" (Stella Benson, This is the End). Inez Haynes Irwin, writing in The Californiacs (1921), praises what was then the superior quality of California fog, saying it is "Not distilled from pea soup like the London fogs; moist air-gauzes rather, pearl-touched and glimmering."
In the animated television Christmas feature Rudolph the Red-Nosed Reindeer (1964), the characters Rudolph, Hermey and Yukon Cornelius are travelling through a thick fog when the following exchange takes place: Yukon Cornelius: "This fog's as thick as peanut butter!" Hermey: "You mean pea soup." Yukon Cornelius: "You eat what you like, and I'll eat what I like!"
The second chapter of the book The Woman in Black (1983) by Susan Hill is titled "A London Particular" and mentions the thick, dense fog of London, which Arthur Kipps witnesses on his journey to work at his solicitors' office.
- Fog Investigation and Dispersal Operation (FIDO) – an aircraft landing aid intended to allow safe flying during the extremes of 'Pea souper' fog
- New York Times, April 2, 1871, pg. 3: "London... fog the consistency of pea-soup..."
- Jo Swinnerton (2004-10-01). The London Companion. ISBN 978-1-86105-799-0
- David Urbinato (Summer 1994). "London's Historic "Pea-Soupers"". United States Environmental Protection Agency. Retrieved 2006-08-02.
- "Deadly Smog". PBS. 2003-01-17. Retrieved 2006-08-02.
- Text of Fumifugium
- HTML text of Fumifugium.
- He shewes that 't is the seacoale smoake That allways London doth Inviron, Which doth our Lungs and Spiritts choake, Our hanging spoyle, and rust our Iron. Lett none att Fumifuge be scoffing Who heard att Church our Sundaye's Coughing. from; "Ballad of Gresham College". Original text.
- Landsberg, Helmut Erich (1981). The urban climate. Academic Press, New York, p.3.
- John Sartain (1820). Annals of the fine arts. London, Sherwood, Neely, and Jones, digitised by Moore College of Art, Philadelphia, p.80
- Fouquet, Roger et al. (June 2001). External Cost and Environmental Policy in the UK and the EU (PDF). Imperial College Centre for Energy Policy and Technology. p. 18. ISBN 1-903144-02-7.
- Bell, Michelle L.; Michelle L. Bell; Devra L. Davis; Tony Fletcher (January 2004). "A retrospective assessment of mortality from the London smog episode of 1952: the role of influenza and pollution". Environ Health Perspect 112 (1): 6–8. doi:10.1289/ehp.6539. PMC 1241789. PMID 14698923.