Historical Parallels – The Great London Smog of 1952

As anyone who has attended a majority of the classroom-based courses that I have delivered will know; I believe a case study from the past can assist in helping students understand the problems of today. This can be a great learning experience. In regards to air pollution, I’m not aware of a better case study than that of The Great London Smog of 1952.

The Great London Smog of 1952

The Great London Smog occurred in December 1952 and resulted in the deaths of around 12,000 people, and thousands of people became ill. The smog occurred for a period of 14 days in total. In the UK this case study – in my opinion is not discussed enough. It doesn’t seem to have permeated the national conscience quite as much as incidents that have caused much less loss of life or illness. Yet it can teach us a lot and has significant modern-day parallels. Poor urban air quality is a battle we are still fighting today.

However, the death rate is likely to be much greater than the official figures stated. The government at the time stopped counting deaths not long after the incident finished, although people died months after as a result of the incident. Smog in London was a common occurrence and was known by the name of ‘Pea Souper’. This was due to the density of the smog and its ability to blank out sunlight. What we are considering here is not just a light bit of smoke in the air; the smog was all enveloping making the day seem like night. To the extent that gaining entry into buildings such as the cinema and theatre performances had to be cancelled, as the audience could not see the performance! The source of the smog was largely from the burning of coal in several power stations across the city, industry, homes and emissions from transportation. These would consist of: sulphur dioxide, oxides of nitrogen and particulate matter to name just a few.

Weather Conditions and Pollutants

However, it is not just about the pollutants. The 14-day period of the smog also coincided with a low-level temperature inversion across the city. Conditions in the atmosphere relatively close to the ground usually involve a decrease in temperature with altitude. Such conditions allow pollutants to escape into the air and disperse easily. This formed an inversion; resulting from a warm front moving above cold close to ground air and resulting in an increase in temperature with altitude. Consequently the warm air acts as a blanket that stops pollutants from dispersing, and they build up at ground level.

Following the smog eventually laws were introduced that aimed to curb the pollution that caused the smog. This included the introduction of smokeless zones and the limitations of releases of air emissions from industry. Indeed, these laws are still in place today in the form of The Clean Air Act 1992.

Have we learnt from History?

However, I don’t believe that we have learnt a great deal from this incident. For example, in London and other urban areas in the UK there is a significant problem with Nitrogen Dioxide breaching safe levels, on a regular basis. Around the world there are still significant problems with air pollution. If you complete an internet search it won’t take long to find images that depict those from The Great Smog, particularly in developing countries. Unfortunately, human beings have a tendency to forget about major incidents and revert back to a ‘business as usual’ approach. We do not always learn from past mistakes. What we shouldn’t do is wait until another serious incident like this occurs again.

It’s easy to think of major incidents like this as just ‘history’. Deemed to be thought of as a past incident that has no real lessons to be learnt in modern times. Moreover, if we forget about such incidents and do not study them, we are more likely to repeat these catastrophic incidents.

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John Binns BSc (Hons), MSc, MSc, MIEMA

With over 19 years’ experience working in environment management, John Binns BSc (Hons) MSc MIEMA is an experienced environmental tutor and consultant with knowledge of health and safety management.