A multi-year study of over 3,400 primary school children reveals that London's Ulez has contributed to improved lung growth among children, highlighting the health benefits of cleaner urban air.
- Children in London showed faster lung growth after Ulez introduction
- Nitrogen dioxide pollution levels fell more sharply in Ulez areas
- Active travel to school increased, supporting healthier lifestyles
What happened
London introduced its Ultra Low Emission Zone (Ulez) in April 2019 to reduce traffic pollution by limiting the most polluting vehicles in central London. Over the next several years, the zone expanded to cover broader parts of the city. Researchers from Queen Mary University of London conducted a five-year study involving more than 3,400 children aged six to nine across London and the comparator city of Luton, which does not have a similar clean air scheme.
The study measured lung function annually from 2018 to 2022, noting improvements after Ulez implementation. Before the scheme, London children had lower lung capacity and higher exposure to nitrogen dioxide, a harmful pollutant linked to vehicle exhausts. After Ulez came into force, nitrogen dioxide levels dropped faster in London than in Luton. Correspondingly, London children’s lung growth increased at a quicker rate, closing gaps seen before 2019.
Why it feels good
The improved lung development among children signals real, health-focused benefits from cleaner air beyond environmental indicators alone. Key lung function markers such as forced expiratory volume in one second (FEV₁) and forced vital capacity (FVC) showed faster growth in London kids post-Ulez, bringing them closer to the levels seen in less polluted areas. Experts say these changes could have lifelong positive effects, reducing risk of respiratory and cardiovascular issues in adulthood.
Beyond pollution reduction, the Ulez also appears to encourage healthier habits. Nearly half of the London children previously driven to school switched to walking, cycling, or public transport following Ulez’s introduction. This shift towards active and sustainable travel especially among those living farther from school further supports children's overall well-being and fitness.
What to enjoy or watch next
Monitoring the continued expansion of Ulez and similar initiatives in other cities will be important to assess long-term health impacts and guide public policy. As London’s clean air zone now covers the entire capital, future studies may reveal even broader benefits across different age groups and communities.
Additionally, promoting active travel alongside pollution reduction offers a comprehensive approach to improving urban health. Families, schools, and local governments might look for ways to support walking and cycling safely as part of everyday life. These practical changes, combined with cleaner air, create a refreshing example of how urban planning can nurture healthier generations.