Overview
- The peer‑reviewed CHILL study, published Tuesday, followed more than 3,400 children aged 6–9 from 84 primary schools in London and Luton with annual lung function tests from 2018 to 2022.
- Researchers found children’s NO2 exposure in London fell about twice as fast as in Luton and that London children’s forced expiratory volume in one second (FEV1) rose roughly 10 ml per year more, bringing their FEV1 to parity with Luton by year five.
- The share of London children with clinically impaired lung function fell from 14% to 9% over the study period compared with a fall from 9% to 7% in Luton, a change the authors link to local air‑quality improvements after ULEZ.
- Lead researchers and health groups say the results strengthen the case for ambitious clean‑air zones, while independent experts caution that pandemic travel changes, shifts in walking and cycling, and other unmeasured factors could have influenced the findings.
- Policy debate is likely to intensify because the study shows direct child health benefits but leaves questions about costs to drivers and small businesses, and notes that pollution in many places still exceeds WHO guideline levels.