London's Ultra-Low Emission Zone Linked to Significant Boost in Children's Lung Health, Study Reveals

A measurable improvement in children’s lung health has been recorded in London following the implementation of traffic restrictions aimed at reducing air pollution, according to a study published in The Lancet.

Scientists compared the lung capacity of children in Luton with that of children residing in London. Initially, children in the UK capital had smaller lungs prior to the introduction of London's ultra-low emission zone (Ulez). Over a five-year period, however, this disparity shifted, resulting in similar lung size and health levels between the two groups. Furthermore, the study revealed that the proportion of children with clinically impaired lung function decreased twice as much in London compared to Luton during the same timeframe.

Introduced in central London in April 2019 and expanded to outer London in August 2023, Ulez charges drivers operating older, higher-polluting engines to enter the city. The policy aims to reduce nitrogen dioxide levels, a pollutant associated with respiratory infections and breathing and circulation conditions such as asthma.

Professor Lucy Chappell, chief scientific adviser at the Department of Health and Social Care and chief executive officer of the National Institute for Health and Care Research, stated that the findings provide crucial evidence on real-life interventions that deliver life-changing health benefits for children. Ian Mudway, associate professor in the School of Public Health at Imperial College London and joint senior author of the study, emphasized that bold and ambitious measures are necessary to improve the lives of children in high-traffic urban environments.

The 2023 Ulez expansion, championed by Mayor Sadiq Khan, previously faced criticism from opponents who argued it would penalize poorer Londoners without adequately solving the city's air quality issues. While the mayor's office maintains that nitrogen dioxide levels have dropped, they still exceed World Health Organisation recommendations.

Helen Wood, a research fellow at Queen Mary University of London and the study's lead author, noted that while the reduction in air pollution was previously known, the simultaneous improvement in children's lung health is a vital finding. Conversely, Stephen Burgess, professor of bio-statistics at the University of Cambridge, cautioned against definitive causality, suggesting external factors like the pandemic might have contributed, making it questionable whether Ulez was solely responsible.

Mayor Sadiq Khan stated that the research validates the Ulez expansion and supports his decision to extend cleaner air benefits to every child in London. Led by researchers from Queen Mary University of London in collaboration with Imperial College London and the Universities of Bedfordshire, Oxford, Cambridge, Edinburgh and Southern California, the study evaluated more than 3,400 children and was funded by the NIHR.