London children’s lung growth caught up as traffic pollution fell

Children in London whose lung capacity initially lagged behind peers in Luton showed accelerated growth after the capital introduced its Ultra Low Emission Zone in 2019. By the end of a five-year study, their capacity on the main lung-function measure had reached nearly the same level as the comparison group, suggesting some pollution-related impairment may improve during childhood.

Researchers followed more than 3,400 children aged six to nine from 84 primary schools, testing them annually from 2018 to 2022. London participants’ exposure to nitrogen dioxide fell faster than in Luton, while the proportion with clinically impaired lung function dropped from 14% to 9%. Luton recorded a smaller decline, from 9% to 7%. A second lung-capacity test also showed improvement, though less strongly.

The observational study cannot prove that Ulez alone caused the recovery. Independent experts noted possible influences including pandemic-era changes, increased walking or cycling, and other differences between the cities. Still, the comparison strengthens evidence that cleaner urban air can support children’s developing lungs. Pollution in both cities remains above World Health Organization guidelines, so further gains are possible.