August 18, 2026

ULEZ and lung function in children in London

Traffic-related air pollution is a risk factor for lung disease.  Clean air zones are public health policy interventions aiming to reduce traffic-related air pollution, and a new study has been carried out to investigate whether they are associated with lung health in young children.

The Children’s Health in London and Luton (CHILL) study is a prospective two-arm parallel cohort study looking at children’s lung function growth trajectories in Central London (the original area of ULEZ implementation) and Luton (a comparator site with no clean air zones), and has been published in the Lancet Public Health.

The five-year study aims to determine if air quality improvements following the introduction of ULEZ were associated with lung growth in children living in London – the study involves over 3,400 children aged 6-9 years from 84 primary schools in London and Luton.  The researchers looked at the children’s forced expiratory volume in one second (FEV₁), a measurement of how much air can be forcefully exhaled from the lungs in one second, in relation to exposure to nitrogen dioxide (NO₂), the pollutant most reflective of exhaust pollution.

Journalists came to this press briefing to hear from the authors of the study about their results. 

Speakers included:

Prof Chris Griffiths, Professor of Primary Care, Wolfson Institute of Population Health, Queen Mary University of London; and University of Oxford

Dr Helen Wood, Research Fellow in Mixed Methods, Wolfson Institute of Population Health, Queen Mary University of London

Prof Gurch Randhawa, Professor of Diversity in Public Health; Director of the Institute for Health & Wellbeing Research, University of Bedfordshire

Dr Ian Mudway, Associate Professor in the School of Public Health; member of the MRC Centre for Environment and Health, Environmental Research Group, Imperial College London

This Briefing was accompanied by an SMC Roundup of comments.