Key facts
- Children's lung capacity and function improved after London's Ultra Low Emission Zone (Ulez) was introduced.
- The study compared 1,664 children in London with 1,750 in Luton, a control town.
- London children's lung size and health improved to levels comparable with those in Luton after Ulez.
- Exposure to nitrogen dioxide fell twice as fast in London as in Luton within five years of Ulez.
- Researchers stated the findings provide strong evidence that clean-air zones can prevent harm to children's health.
A study examining London schoolchildren has found that their lungs grew bigger and healthier after the implementation of the Ultra Low Emission Zone (Ulez), which restricts the most polluting vehicles from entering the city. Researchers observed a restoration of lung capacity that had previously been stunted by exposure to traffic pollution.
The study, which monitored 1,664 children aged six to nine in London and 1,750 in Luton (a control town without a clean air zone) between 2018 and 2022, found that initial measurements showed London children had significantly smaller lungs. However, after Ulez came into force in 2019, the size and health of the London children's lungs improved until they were comparable with those of the children in Luton. These improvements correlated strongly with air quality changes, with nitrogen dioxide exposure falling twice as fast in London as in Luton within five years.
Professor Chris Griffiths, a joint senior author, stated that the findings provide the strongest evidence to date on how to prevent the harms of traffic pollution on children's health, advocating for ambitious clean-air zones globally. Mayor Sadiq Khan, who introduced Ulez, acknowledged the difficult decisions involved but emphasized the policy's role in saving lives and improving public health, noting that Londoners' children are now reaping the rewards. Health minister Karin Smyth echoed these sentiments, highlighting the study's contribution to understanding how reduced air pollution supports normal lung growth and reduces the risk of adult respiratory illnesses.
However, Stephen Burgess, a professor of biostatistics at the University of Cambridge not involved in the research, noted that it is unclear if the observed changes are solely attributable to Ulez, suggesting other factors like the COVID-19 pandemic's impact on pollution levels could be at play. Nevertheless, he acknowledged the study's importance and the encouraging evidence it provides for the benefits of urban environmental changes on children's lung development.