Ulez led to better lung size and function among London children, study finds

Ulez Led to Better Lung Growth in London Children

Wanderstayfinder.com – A new longitudinal study confirms that Ulez led to better lung size and function among London schoolchildren within roughly five years of the zone’s 2019 launch. Children who had entered the programme with measurably smaller lungs than peers in a comparable town outside the zone reached full parity once local nitrogen dioxide levels fell sharply.

The deficit being corrected was not marginal. Earlier cross-sectional work had shown that by ages eight or nine, children in London’s most polluted districts carried five to ten percent less lung capacity than counterparts elsewhere, a shortfall linked to chronic nitrogen dioxide exposure from diesel and petrol engines. Without intervention, that developmental gap elevates adult risk of asthma, chronic obstructive pulmonary disease, cardiovascular disease, and premature death.

Study Design and Findings

Researchers at Queen Mary University of London treated the zone’s rollout as a natural experiment. Before the restriction took effect, they enrolled 1,664 children aged six to nine in London schools and simultaneously recruited 1,750 same-age children in Luton, a town roughly thirty miles north with a similar traffic-pollutant profile but no clean-air mandate. Annual school visits from 2018 through 2022 captured height, weight, and pulmonary-function measurements for every participant.

Baseline data confirmed the expected disparity: London children started with significantly smaller lungs. After the zone became operational, however, the trajectories diverged. London children’s lung capacity improved year over year until it matched the Luton cohort. The speed and magnitude of recovery tracked closely with local air-quality readings; within five years, nitrogen dioxide exposure in the zone declined at twice the rate and by twice the amount observed in the control town.

The finding that Ulez led to better lung development in a previously impaired cohort is, according to the authors, the strongest causal evidence yet that a single, well-enforced traffic policy can reverse a measurable developmental harm in children.

Official Reactions

“Traffic pollution in cities damages children’s health and development,” said Chris Griffiths, professor of primary care at the University of Oxford and Queen Mary University of London and joint senior author of the study. “We provide the strongest evidence yet on how these harms can be prevented. Ambitious clean-air zones should be considered a priority for cities globally with traffic-related air pollution.”

Mayor Sadiq Khan, who had justified the scheme as the world’s largest and most ambitious low-emission zone, welcomed the findings. “Introducing and expanding the Ulez involved some incredibly difficult decisions. I never took them lightly, but I knew that – as mayor – I could not stand by while Londoners young and old lost their lives to a problem it was within my power to solve,” he wrote. Khan added that opponents had “cynically sought to turn questions of public health into a crude culture war,” while London’s children were now “reaping the rewards.”

Karin Smyth, the health minister, described the work as a reminder of how air quality shapes paediatric lung development and said it would help “reduce the risk of respiratory illnesses in adulthood, and support our goal to give every child the best start in life.”

Caveats and Wider Implications

Not every specialist in the field accepted the causal reading without reservation. Commentators in respiratory epidemiology noted that the Luton comparison, while well matched on traffic-pollutant profile, cannot fully control for socioeconomic, dietary, or genetic confounders. The authors themselves called for replication in additional cities before the findings are generalised beyond London.

Still, the study represents the most direct evidence to date that aggressive emission controls can restore normal paediatric lung growth. If replicated, the result strengthens the case for cities worldwide to treat such policies as a