Fog will occur when the air closer to the ground becomes trapped by warmer air above it then the temperatures drop and the moisture in the air condenses causing fog. Now that is a scientific fact, unfortunately London’s fog issues arose not from cool air being trapped, but from air pollution. London has had the reputation as being “foggy” for hundreds and hundreds of years when people began using wood to keep warm but London really became extremely “foggy” when coal began to be used in not only the industries throughout London, but also by households as a way to keep warm because wood was becoming scarce and outrageously priced.
The denseness of the fog in the 1800s was virtually impenetrable and was the cause of many accidents and even deaths because you literally could barely see the hand in front of your face, let alone anyone or anything coming towards you out of that “pea soup.” It was said that London’s fog was not like the white stuff that most of us recognize as such today; instead it was a myriad of colors from reddish brown to greenish yellow and on occasion the smell of sulphur would hang in the air. The expression “thick as pea soup” was a popular one in and around London during this time as locals would call it a “pea souper,” meaning the fog was as thick as pea soup that day. Today it is now known as smog not fog.
The pinnacle of London’s “fog” came in December of 1952 when there was unseasonable cold weather that had lasted for several weeks previous to this last deadly “fog.” With the cold weather came a higher amount of coal being used to keep warm. At that time it would have been upwards of a million households burning extra coal to keep warm, not to mention the industries that also used coal. On December 5th, a light fog had been lingering near the ground while black soot, sulphur dioxide and tar emulsions were all being pumped out into the skies above London.
As night approached on December 5th, these heavy coal particles and large amounts of soot began to settle into that light fog which had already become thicker due to weather conditions. All these conditions combined to bring the city of London to her knees making visibility nil and leaving all modes of transportation at a standstill. This smog enveloped London for an unheard of five days, and unfortunately was able to penetrate into people’s homes causing a number of deaths, upwards of 12,000 in the days not only of this smog being grounded but in the weeks after. Many died from pneumonia, bronchitis, heart attacks, lung inflammations, and damaged respiratory systems. This spurred on the British government to address the problem and in 1956 the Clean Air Act was enacted. Today thankfully London is no longer encompassed in a lot of “pea soupers.”
