Pea soup fog

Pea soup fog refers to a very thick and often yellowish, greenish, or blackish fog caused by air pollution that contains soot particles and the poisonous gas sulfur dioxide. This type of fog is also known as a "black fog," "killer fog," or "smog." Historically, pea soup fog was a common occurrence in urban areas of the United Kingdom and the United States during the 19th and early 20th centuries, particularly in cities like London and Pittsburgh. The term "pea soup" is used to describe the fog because its density and color are similar to that of pea soup.

Causes

Pea soup fog forms when smoke and soot particles from industrial operations and domestic fires mix with fog under certain conditions. These conditions include high humidity, lack of wind, and cold temperatures. The presence of sulfur dioxide, a byproduct of burning coal, reacts with the moisture in the air to form sulfuric acid, contributing to the fog's thickness and health hazards.

Historical Significance

One of the most notorious instances of pea soup fog occurred in London in December 1952, known as the Great Smog of 1952. This event lasted for four days and caused widespread health problems, leading to thousands of deaths. The Great Smog brought significant attention to the dangers of air pollution and led to the creation of the Clean Air Act 1956 in the UK, which aimed to reduce air pollution by regulating the burning of coal and moving power stations away from cities.

Health Effects

Pea soup fog poses serious health risks due to the high concentrations of pollutants, including sulfur dioxide and particulate matter. Short-term exposure can irritate the eyes, nose, throat, and lungs, leading to coughing, wheezing, and shortness of breath. Long-term exposure can exacerbate chronic respiratory conditions such as asthma and bronchitis, and increase the risk of heart and lung diseases.

Modern Occurrences

While the frequency and severity of pea soup fogs have significantly decreased in developed countries due to stricter air quality regulations and the shift towards cleaner energy sources, they can still occur in areas with high levels of industrial pollution and in developing countries where environmental regulations are less stringent.

Prevention and Control

Efforts to prevent and control pea soup fog focus on reducing air pollution through various measures. These include implementing clean air regulations, transitioning to cleaner energy sources, such as natural gas, renewables, and nuclear power, and encouraging the use of public transportation and electric vehicles. Additionally, urban planning and green infrastructure, such as planting trees and creating green spaces, can help absorb pollutants and improve air quality.