Impact of the Ultra Low Emission Zone on lung function growth in children in London, UK: a prospective parallel cohort study.

The CHILL study followed 3,414 children in London and Luton for five years to assess whether London’s Ultra Low Emission Zone (ULEZ) improved lung growth by reducing air pollution. Lung function was measured annually using a Vitalograph Alpha spirometer, which collected FEV₁ data used to track lung growth and compare outcomes between cohorts. Children in London showed greater lung function improvement, supporting clean air zones as a public health intervention