Media Briefings

LIFELONG DAMAGE FROM FOETAL EXPOSURE TO AIR POLLUTION: Evidence from the Great London Smog

  • Published Date: March 2016

Being exposed to severe air pollution in utero not only causes childhood ill health but also means people are less likely to have A levels or a degree and less likely to be in work in later life. These are among the findings of research by Alastair Ball, to be presented at the Royal Economic Society's annual conference in Brighton in March 2016.

His study compares people whose mothers were in London during the Great Smog of 1952 – when pollution levels were much closer to what is seen in modern day Beijing or Mumbai – to people who were not affected. Analysing data on almost 7,000 people from the Office for National Statistics (ONS) Longitudinal Study, it finds that affected people are 5% less likely to hold a degree, and men aged over 50 were 4% less likely to be in any kind of employment.

This is still likely to be an underestimate of the damage. Being exposed to air pollution could also mean that only the strongest children survived to be observed in the first place, all of whom would then be less healthy over their lifetimes. The author comments:

‘It is well established that adult exposure to pollution in cities like Beijing or Mumbai can have catastrophic effects on health, but there is still too little known about the effects of foetal exposure to include them in official estimates of the costs of pollution.’

‘It is becoming clear that this omission is important. Foetal exposure to pollution has significant effects both through its effect on stillbirth and its effect on the long-term health of survivors. If governments in developing countries are to make informed decisions about pollution legislation, then more needs to be done in cataloguing this channel.’

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This study provides new evidence about the long-term consequences of in utero exposure to atmospheric pollution. A child’s exposure during pregnancy depends on factors such as parental income or nearby industry. This study identifies the effects of foetal exposure by following individuals whose mothers were in London during the Great Smog of 1952, using unaffected cohorts as a comparison group.

Following these individuals was made possible by the ONS Longitudinal Study, which connects information on individuals from multiple rounds of the census. Results from the main sample of 6,830 people show that:

• Individuals affected were 3% less likely to hold an A-level and 5% less likely to hold a degree than individuals in the comparison group.

• There was little effect on employment at 50 years old for women, but men were 4% less likely to be in any kind of employment.

The estimated differences capture two outcomes of the smog:

• First, foetal exposure to pollution can lead to stillbirth, with only the strongest children likely to survive to be observed.

• Second, foetal exposure to pollution can cause damage to the child’s health, meaning that all individuals are likely to be less healthy than they would have been.

As a consequence, these results are likely to be underestimates of the true health effects.

The levels of pollution observed during the Great London Smog were very high, much closer to levels observed during bad days in Beijing or Mumbai than in present day London. It is well established that adult exposure to pollution in these cities can have catastrophic effects on health, but there is still too little known about the effects of foetal exposure to include them in official estimates of the costs of pollution.

It is becoming clear that this omission is important. Foetal exposure to pollution has significant effects both through its effect on stillbirth and its effect on the long-term health of survivors. If governments in developing countries are to make informed decisions about pollution legislation, then more needs to be done in cataloguing this channel.

For levels of pollution in the developed world, such as in London, there is evidence that foetal exposure can lead to low birth weight, which is linked to a wide range of adult diseases, but there is little evidence into how these translate into adult outcomes. This is the focus of Dr Ball’s continuing research.

ENDS


Air pollution, foetal mortality, and long-term health: evidence from the Great London Smog

Contact details
Dr. Alastair Ball
Department of Economics, Mathematics and Statistics
Birkbeck College, University of London
Alastair.Ball@bbk.ac.uk