page_title: 19th-century London
section_title: Fog
hierarchical_section_title: 19th-century London / Pollution / Fog
caption_attribution_description: The Illustrated London News, Volume 10, January to June 1847. A London fog drawn by Duncan. Page 8. Wellcome Images Keywords: illustrated london news; london fog
context_page_description: During the 19th century, London grew enormously to become a global city of immense importance. It was the largest city in the world from about 1825, the world's largest port, and the heart of international finance and trade. Railways connecting London to the rest of Britain, as well as the London Underground, were built, as were roads, a modern sewer system and many famous sites.
context_section_description: Atmospheric pollution caused by burning cheap soft coal created the city's notorious pea soup fog. Air pollution from burning wood or coal was nothing new to London - complaints about the city's dirty atmosphere exist as far back as the 13th century - but the population explosion and industrialisation of the 19th century aggravated both the severity of the fogs and their lethal effects on Londoners.
  
  The fogs were at their worst in the month of November, but occurred frequently throughout the autumn and winter. Sulphur dioxide and soot emitted from chimneys mixed with the natural vapour of the Thames Valley to form a layer of greasy, acrid mist that shrouded the city up to 240 feet (75 metres) above street level. Its most common colour was a greenish-yellow "pea soup", but it could also be brown, black, orange, or grey. At their worst, the poor visibility caused by London fogs could halt traffic and required the street lamps to be lit all day. Conditions for pedestrians were extremely dangerous: in 1873, nineteen deaths were attributed to accidental drowning from victims who fell into the Thames, canals, or docks during foggy weather. There were also increases in crimes like theft, rape, and assault on London streets because of the cover provided by the fog. Charles Dickens Jr. described the "London particular" in his Dictionary of London of 1879: 
   As the east wind brings up the exhalations of the Essex and Kentish marshes, and as the damp-laden winter air prevents the dispersion of the partly consumed carbon from hundreds of thousands of chimneys, the strangest atmospheric compound known to science fills the valley of the Thames. At such times almost all the senses have their share of trouble. Not only does a strange and worse than Cimmerian darkness hide familiar landmarks from the sight, but the taste and sense of smell are offended by an unhallowed compound of flavours, and all things become greasy and clammy to the touch. During the continuance of a real London fog—which may be black, or grey, or more probably orange-coloured—the happiest man is he who can stay at home...Nothing could be more deleterious to the lungs and the air-passages than the wholesale inhalation of the foul air and floating carbon which, combined, form a London fog."
  There was wide awareness of the deleterious health effects of extended fogs in London, particularly upon those suffering from respiratory illnesses. Mortality rates could rise well above average at times of severe fog: 700 extra deaths, for example, were attributed to a particularly bad fog in 1873. The recurrent fogs of January and February 1880 were especially bad, killing an estimated 2,000 people and raising the death rate to 48.1 per 1,000 people, compared to the average of 26.3 per thousand in other English cities.
caption: "A London Fog", from The Illustrated London News (1847)