The introduction of the Ultra Low Emission Zone (ULEZ) in London led to an unexpected recovery in children's lung growth and capacity.

"Examinations of London schoolchildren before and after the introduction of the city’s ultra-low emission zone (Ulez) found a restoration of lung capacity that had been stunted by exposure to pollution." https://www.theguardian.com/environment/2026/aug/18/ulez-better-lung-size-function-london-children

Scientists say they have been “stunned” by the recovery of children’s lungs since the introduction of London’s Ultra Low Emission Zone in 2019. Researchers found that reduced emissions had vastly improved the lung capacity of primary school children whose lung growth had been stunted by pollution.

Scientists find unexpected recovery in children’s lungs after ULEZ cuts pollution Researchers expected cleaner air to prevent further damage to children’s lungs, but a major five-year study found London children instead experienced accelerated lung growth and caught up with their peers outside the capital. https://www.ianvisits.co.uk/articles/scientists-find-unexpected-recovery-in-childrens-lungs-after-ulez-cuts-pollution-91950/