London’s Ultra Low Emission Zone cleaned up the city’s air. Then children’s lungs got bigger

In London, an Ultra Low Emission Zone (ULEZ) was implemented to reduce toxic air pollution by requiring vehicles to meet strict emissions standards or pay a daily fee for driving through the area. This initiative has not only cleaned up the city’s air but also led to improved lung growth in children. Before the ULEZ, London children had stunted lung growth, which put them at risk of asthma, lung diseases, and early death as adults.

A major five-year study published in the Lancet Public Health journal found that after five years of the ULEZ, London children’s lungs had caught up to those of children in Luton, another city in England with similar air pollutants but no low emissions zone. Professor Chris Griffiths, a lead investigator on the study, described the results as "astonishing" and "jaw-dropping."

The children's lung function improved, with their forced expiratory volume in one second (FEV1) increasing by 10 milliliters per year more than children in Luton. The study also showed that London children's exposure to nitrogen dioxide (NO2), a toxic emission from combustion engines, fell twice as fast and more than twice as much as in Luton.

While the study cannot definitively prove causation, researchers are confident that the relationship between lower air pollution levels and improved lung development could be causal. Air pollution is a major environmental cause of death, linked to health impacts like asthma, cancer, and heart disease. A London coroner ruled that air pollution and severe asthma contributed to the death of a nine-year-old girl in 2013.

London's ULEZ expansion in 2022 was specifically aimed at providing better health for children. Despite pollution levels still exceeding World Health Organization standards, the study's findings highlight the importance of clean air zones in delivering better health outcomes for children worldwide.