Does air pollution disrupt sleep?

Sleep is vital. While we sleep, our body performs many essential activities that regulate and support our health. The World Economic Forum has estimated that if individuals simply gained one hour of sleep, moving from six to seven hours a night, this would add $226 billion to the US economy, $76 billion to the Japanese economy, $34 billion to the German economy, and $30 billion to the UK economy.

New research, to be presented at the annual conference of the Royal Economic Society, investigates the connections between air quality and sleep. The research team are all drawn from Imperial College London.

The authors take advantage of a 2016 temporary pedestrianization, known as Paris Respire, of selected Paris neighbourhoods, intended to improve air quality. As discussed below, its design proves especially useful for investigating whether short-term improvements in air quality can lead to changes in sleep.

This matters, given the view that sleep deprivation is pervasive – less than half of people feel that they sleep enough. According to the Rand Corporation, the US loses the equivalent of around 1.2 million working days per year due to people not getting enough sleep. They also find that those who sleep fewer than six hours a night have a 13% higher mortality risk than people who sleep at least seven hours. Given its economic and health importance, understanding what contributes to poor sleep should be a priority.

Researchers are now beginning to investigate how the external environment – including ventilation, temperature, and noise – influences the ability to gain restorative sleep. Given these new insights, it is natural to ask whether poor air quality has a role to play.  According to the World Health Organization, 99% of the world population in 2019 lived in places that exceeded their recommended air quality guidelines. Given the strong links between air pollution and poor respiratory health, it may help in understanding how we sleep.

Studying the direct impacts of air pollution is often quite complex, because there may be other forces at work. The authors take advantage of some useful features of Paris Respire: they rely on the selective implementation of this policy – in terms of hours, days, and areas – to quantify the impact of the policy on traffic, congestion, and a range of sleep outcomes. They combine two large datasets to look into this: (1) an administrative dataset on hourly traffic and congestion, and (2) a novel dataset with daily sleep characteristics for individuals, as tracked by widely available smart sleep mattresses.

The researchers find that the policy of Paris Respire succeeded in reducing traffic and, by extension, traffic-related emissions by approximately 25%. The study attributes a small gain in sleep time, of 2.2%, to the cleaner air experienced during the policy. If this policy were to be enforced uniformly every weekend, this would be equivalent to approximately two more seven-hour night-time sleeps every year. The authors find that sleep for people based in surrounding areas also improved.

This is an instance where even small changes may have large impacts. The new study begins to unveil one of the wider societal benefits to be expected from cleaning the air we breathe, and suggests that the benefits of such policies should be assessed more broadly.

Authors and Contact:

Dr. Dheeya Rizmie

M: 07540 997255

E: dheeya.rizmie14@imperial.ac.uk

Twitter: @dheeyarizmie

LinkedIn: https://www.linkedin.com/in/dheeya/

Dr. Laure de Preux

E: l.depreux@imperial.ac.uk

Twitter: @LauredePreux

LinkedIn: https://www.linkedin.com/in/laure-de-preux-gallone-6450537/

Dr. Marisa Miraldo

E: m.miraldo@imperial.ac.uk

Twitter: @mmiraldo

LinkedIn: https://www.linkedin.com/in/mmiraldo/

Notes to Editors:

The press release is highlighting research papers presented at the RES Annual Conference 2022 (#RES20220) for further information, please contact j.randalledwards@res.org.uk on 07970 201456 if you want the link to the full paper.

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