A landmark five-year study has delivered the most definitive medical evidence to date that Clean Air Zones actively reverse childhood lung stunting and improve respiratory health.
Led by Queen Mary University of London in collaboration with Imperial College London, the Universities of Oxford, Cambridge, Edinburgh, Bedfordshire, and Southern California, the Children’s Health in London and Luton (CHILL) study tracked more than 3,400 primary school children aged 6–9 across 84 schools between 2018 and 2022.
The Key Findings:
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Catching Up on Lung Capacity: Prior to the introduction of London’s Ultra Low Emission Zone (ULEZ), children in London had significantly smaller lung capacities compared to their peers in the control group in Luton. Following the implementation of the ULEZ, London children experienced accelerated lung growth, catching up to the lung capacity of children in Luton.
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Plummeting Nitrogen Dioxide (NO₂): In the five years after ULEZ was introduced, London children’s exposure to toxic NO₂ traffic pollution fell twice as fast and more than twice as much as those in Luton.
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Reversing Impairment: The proportion of children suffering from clinically impaired lung function in London dropped dramatically from 14% down to 9% over the study period.
What did the team say?
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John Curtis:
"It’s proof of what we have always known. Reducing vehicle emissions directly improves children's respiratory health, it makes a genuine, lifelong difference."
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Paul Kirby:
"During the three months of total lockdown with nothing on the road, there was not one single asthma-related death in the country. Clean air policy saves lives."
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Sara Sloman:
"This is the perfect intersection of policy, real-world data, and public opinion. Drivers are looking at the evidence and realising it's time to act."
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Sam Clarke:
"I moved my kids away from the South Circular because of school pollution. It’s fantastic to see everyone finally recognising that clean air zones deliver a material difference."