Full Breakdown
London’s Ultra-Low Emission Zone Linked to Accelerated Lung Growth in Children
8/26/2026, 6:36:49 AM
Core Findings of the CHILL Study
A five-year investigation led by Queen Mary University of London and published on 18 August in *The Lancet Public Health* compared lung development in more than 3,400 primary-school children aged 6–9 from London and Luton. At the start, London children had smaller lungs. Over 2018-2022, lung growth in the London cohort accelerated, eliminating the deficit. Forced expiratory volume in one second (FEV1) increased by an additional 10 mL per year for each year that nitrogen-dioxide (NO2) exposure fell, and by the study’s end lung size and function were comparable between the two groups. The proportion of London children with clinically impaired lung function fell from 14 % to 9 %, while Luton’s rate declined from 9 % to 7 %.
Background and Policy Context
London’s Ultra-Low Emission Zone (ULEZ) was introduced in central London in 2019, expanded to the North and South Circular roads in 2021 and to all boroughs in 2023. The policy charges drivers of higher-emitting vehicles to cut traffic-related pollutants, chiefly NO2. Since its introduction, ULEZ has been a focal point of political contention, with Conservative ads targeting Mayor Sadiq Khan and opposition from Labour leader Keir Starmer and Greater Manchester Mayor Andy Burnham. Protest actions have included vandalism of enforcement cameras.
Timeline of Key Developments
- 2019 – Central London ULEZ launched.
- 2021 – Expansion to North and South Circular roads.
- 2023 – City-wide expansion to all boroughs.
- 2018-2022 – CHILL study monitors children in London and Luton.
- 18 August 2026 – Study results published in *The Lancet Public Health*.
Official Statements and Responses
Health Minister Karin Smyth called the study a “powerful reminder” of how air-quality improvements can restore normal lung growth. Lucy Chappell, Chief Scientific Adviser at the Department of Health and Social Care, said the research provides crucial evidence that clean-air zones deliver health benefits for children. Researchers including Professor Chris Griffiths and Associate Professor Ian Mudway said the findings offer strong evidence that traffic-related pollution harms can be prevented through ambitious clean-air policies.
Criticism and Opposition
Opponents have questioned ULEZ’s cost-benefit balance. Conservative ads have targeted Mayor Khan, while Labour leader Keir Starmer urged the mayor to “reflect” on the expansion. Andy Burnham criticised the removal of a clean-air zone in his region. Environmental activist Rosamund Adoo-Kissi-Debrah has called for greater subsidies to help owners replace older vehicles. Protest groups identified as “Blade Runners” have vandalised enforcement cameras, reflecting public resistance to daily charges on higher-emitting vehicles.
Conflicting Reports and Gaps
The CHILL study shows a strong association between reduced NO2 exposure and accelerated lung growth but does not prove ULEZ alone caused every health improvement. Researchers note that other factors, such as housing or lifestyle changes, were not isolated. Both London and Luton still exceed WHO air-quality guidelines, indicating further reductions are needed. No alternative quantitative assessments of lung outcomes were presented, leaving uncertainty about the long-term durability of the gains.
