London's Dark Days: Air Pollution's Deadly History

London has had poor air quality since at least the 13th century, with the diarist John Evelyn writing about the inconveniencie of the aer and smoak of London [sic] in 1661. However, the Great Smog of 1952 was far worse than anything the city had ever experienced before. It is thought to be the worst air pollution event in the UK's history and led to the passing of the Clean Air Act in 1956. The smog was caused by a combination of industrial pollution and high-pressure weather conditions, which trapped emissions from factories and domestic fires near ground level. It lasted for five days, from 5 to 9 December 1952, and resulted in thousands of deaths.

The Great Smog of 1952

London has long struggled with air pollution. As early as the 13th century, the burning of coal was causing polluted fog in the city. The situation worsened as London expanded, and complaints about smoke and pollution increased in the 1600s. Ultimately ineffective legislation, such as the laws passed under King James I to restrict coal burning, failed to improve the situation. By the 19th century, "London fog" or "pea-soupers" had become a hallmark of the city.

However, the air pollution event known as the Great Smog of 1952 stands out as a particularly severe episode in London's history. Lasting from Friday, December 5 to Tuesday, December 9, 1952, the Great Smog was caused by a combination of industrial pollution and high-pressure weather conditions. An anticyclone settled over London, trapping cold air below warm air and preventing the dispersal of emissions from factories and domestic fires. The smoke and fog brought London to a near standstill, with transportation severely restricted and indoor plays and concerts cancelled due to reduced visibility.

The smog had devastating health consequences for the population of London. It caused a huge spike in deaths and hospitalizations related to respiratory issues, with government medical reports estimating up to 4,000 deaths directly attributed to the smog. More recent research suggests that the total number of fatalities was significantly higher, with estimates ranging from 10,000 to 12,000 deaths. The smog also affected livestock, with reports of cattle choking to death in the fields.

The Clean Air Act of 1956

London's air pollution was at its worst in December 1952, when the "Great Smog" blanketed the city. This event highlighted the deadly consequences of air pollution, with an estimated 12,000 deaths attributed to the smog.

In response to this crisis, the Clean Air Act of 1956 was enacted to address the smog and air pollution resulting from coal burning and industrial activities. This legislation built upon earlier efforts to regulate pollutants, particularly in London, where air quality had been a longstanding issue.

The Act gave local authorities the power to regulate emissions of smoke, grit, dust, and fumes from industrial sources, such as furnaces and boilers. It established the Clean Air Council, chaired by the Minister of Housing and Local Government, to advise on and monitor the progress of air pollution abatement in England and Wales.

The Industrial Revolution

London's poor air quality has been a concern since at least the 13th century, with the diarist John Evelyn writing about "the inconveniencie of the aer and smoak of London" in 1661. However, the Industrial Revolution significantly worsened air pollution in London, leading to severe health and economic consequences.

During the 19th century, the onset of industrial growth led to a sharp increase in air pollution levels in London. The city became known as the "Big Smoke", with concentrations of suspended particulate matter (SPM) reaching up to 623 micrograms per cubic metre. Mortality rates from bronchitis soared, rising from 25 deaths per 100,000 inhabitants in 1840 to 300 deaths per 100,000 in 1890. At its peak, one in 350 people died from bronchitis in London due to the poor air quality.

While London's air pollution has improved since the Industrial Revolution, it continues to be a health concern. The Clean Air Acts of 1956 and subsequent environmental legislation have helped reduce pollution levels, but London still struggles with air quality issues. Today, the main pollutants of concern in London are fine particulate matter (PM2.5) and nitrogen dioxide (NO2), which are generated from urban transport, heating of homes, and industrial activities.

In recent years, there has been a significant reduction in the number of people living with illegal levels of nitrogen dioxide, with a 94% decrease between 2016 and 2019. This has been achieved through various measures, including charges for polluting vehicles, the promotion of cleaner vehicles, the use of low-emission buses, and the expansion of protected spaces for cycling.

Health costs and deaths

London's poor air quality has been a concern since at least the 13th century. John Evelyn wrote about "the inconveniencie of the aer and smoak of London" in 1661, in the first book on air pollution, titled Fumifugium. However, the Great Smog of 1952 was far worse than anything the city had previously experienced. It is considered the worst air pollution event in the history of the United Kingdom, and it had a profound impact on environmental research, government regulation, and public awareness of the link between air quality and health.

The Great Smog was caused by a combination of industrial pollution and high-pressure weather conditions. An anticyclone settled over London, trapping cold air below warm air, which prevented emissions from factories and domestic fires from escaping into the atmosphere. As a result, the city was blanketed in a dense fog that lasted for five days, from December 5 to December 9, 1952. This fog severely disrupted transportation, with public transport ceasing to function except for the London Underground. Ambulance services were also affected, leaving people to make their own way to hospitals. The smog caused a spike in deaths and hospitalizations due to pneumonia and bronchitis, with thousands of fatalities. Marcus Lipton, a member of the House of Commons, estimated that the fog caused 6,000 deaths, while 25,000 more people claimed sickness benefits. Research published in 2004 supports this claim, suggesting that the number of deaths was about 12,000, which is close to the figure estimated by E. T. Wilkins, the UK's top pollution expert at the time.

The Great Smog had long-term health impacts as well. Individuals who were foetuses or infants during the smog were found to have lower intelligence and worse respiratory health later in life. The smog also had economic consequences, interrupting economic activities and contributing to an increase in crime rates.

The Clean Air Act of 1956 was passed as a direct response to the Great Smog, marking a significant event in the history of environmentalism. This act established smoke-free zones and restricted the burning of coal in domestic fires and industrial furnaces. Homeowners were incentivized to switch to alternative heating sources, such as oil, natural gas, and electricity. These measures, along with economic restructuring, improved energy sources, and increased environmental regulations, contributed to a decline in air pollution in London.

Reduction in air pollution

London's air pollution has been a problem since at least the 13th century, with the diarist John Evelyn writing about "the inconveniencie of the aer and smoak of London [sic]" in 1661. However, the Great Smog of 1952 was the worst air pollution event in the UK's history, leading to approximately 12,000 deaths. This event prompted several changes and regulations to reduce air pollution.

One of the key factors in reducing air pollution in London was the shift from coal to gas for heating and cooking. The uptake of gas cookers increased significantly in Great Britain during the 1800s and 1900s. Gas is a much cleaner fuel than coal, so this transition likely contributed to the decline in air pollution.

The introduction of environmental regulations and legislation also played a crucial role in improving air quality. The Public Health Act for London in 1891 imposed financial penalties on businesses that did not adopt cleaner energy practices. The Clean Air Acts of 1956 and 1968 further addressed air pollution issues, and financial incentives were offered to households to switch from open coal fires to alternatives like gas fires or coke, which produces minimal smoke.

Innovations in urban design and stronger environmental regulations have helped reduce industrial pollution. The City of London (Various Powers) Act 1954 and the Clean Air Acts have set new, tighter air quality targets. London's "Ultra Low Emission Zone" (ULEZ) uses road fees to reduce greenhouse gas emissions and create a cleaner, healthier, and more equitable city. The implementation of Low Emission Bus Zones has also led to significant reductions in pollution levels.

London continues to face serious environmental challenges and aims to have the best air quality of any major city by 2050. This involves transitioning to a zero-emission city, improving transport networks, and reducing exposure to harmful pollution, especially in priority locations like schools.

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