London clean air zone linked to improved child lung development in five-year study

Five-year study tracks childhood lung growth

Researchers led by Queen Mary University of London tracked the respiratory health of more than 3,400 children aged six to nine between 2018 and 2022. The study recruited pupils from 84 primary schools across London and Luton, using Luton as a control site due to its similar traffic pollution mix and lack of a clean air scheme. Before London launched its Ultra Low Emission Zone (Ulez) in April 2019, children in the capital had significantly smaller lung capacity than their counterparts in Luton. By 2022, after the implementation of the £12.50 daily charge on non-compliant vehicles, lung size and performance among London pupils accelerated to match levels recorded in Luton. Nitrogen dioxide exposure among London pupils fell twice as fast as in Luton over the five-year monitoring period.

Reversal in impaired lung capacity rates

The study, published in The Lancet Public Health, reported a marked decrease in the proportion of children suffering from clinically impaired lung function. In London, the rate of impaired lung capacity dropped from 14% before the policy took effect to 9% by 2022. In Luton, where no low emission zone existed, the proportion experienced a smaller decline from 9% to 7% across the same timeframe. Experts noted that stunted lung growth by early adulthood raises long-term vulnerabilities to asthma, cardiovascular conditions, metabolic illness, and early mortality. Lead author Helen Wood emphasized that while the findings confirm measurable health gains, ambient air quality across both urban areas still fails to meet World Health Organization benchmarks.

We already knew that the Ulez reduced air pollution but now we know that children's lung health has improved at the same time, which is a really important finding for children and parents living in London.

Policy rollout and political reactions

The Ulez scheme was first introduced by London Mayor Sadiq Khan in central London in 2019 before expanding to inner London in 2021 and across all Greater London boroughs in 2023. Khan pointed to earlier research from Imperial College London indicating that estimated deaths associated with air pollution in the capital fell by roughly 40% between 2019 and 2024. The study received funding from the UK government through the National Institute for Health and Care Research. Health Minister Karin Smyth endorsed the published data, describing it as a direct demonstration of the connection between urban air quality and respiratory growth.

Calls for nationwide clean air expansion

Clean air advocates used the research findings to push for wider environmental regulation across the United Kingdom. Rosamund Adoo-Kissi-Debrah, whose eight-year-old daughter Ella died from an asthma attack in Lewisham in 2013 and became the first person in the UK to have air pollution recorded as a cause of death, urged national leaders to act. She appealed directly to the prime minister and regional mayors to replicate London's policy by establishing clean air zones in other cities and passing a new Clean Air Act. The campaigner stated that protective environmental measures should not remain limited to the capital.

London children shouldn't be the only ones who are breathing clean air.