Where is pea soup fog found and what is it?

Answer 1

Easier to start with where pea soup fog used to be found. In the 19th century and up to the late 1950's a pea soup fog used to be found in London and most major cities of Britain. It was a very dense fog made all the more dense by the products of thousands of domestic and industrial coal burning fires. The combustion products rich in sulphur compounds gave the fog a sickly greeny yellow colour which in the popular imagination looked like pea soup. So thick was the fog and so poor the street lighting that I can remember when I was a child in the industrial midlands of the UK the conductors of buses having to lead the bus driver by walking in front of the bus using a hand held torch. It could take a long time to get home! In London the pea- souper was sometimes known, especially in the 19th. century, as the London Particular. Fortunately with the introduction of clean air legislation which outlawed the burning of coal in cities and other densely populated areas the pea soup fog disappeared in the 1960's.

Answer 2

"Pea soup fog" is fog which is "as thick as pea soup." The expression derives from London, England, which was famous for particularly thick fogs due not only to its terrain in a river valley but also to large quantities of industrial pollution in the air. Now that the air above London is cleaner, the fogs are not as "pea-soupy" as they were.