Archive · 21 Aug 2026
London Study Finds Cleaner Air May Improve Children’s Lung Growth
Children’s lungs keep growing as they get older.
Dirty air from traffic can make it harder for lungs to develop well.
Researchers studied children in London and Luton for five years.
London introduced a cleaner-air zone that reduced some pollution.
At first, London children had slightly smaller lungs than children in Luton.
Over time, their lungs grew faster than the lungs of the children in Luton.
After four years, the difference had almost disappeared.
The study suggests that cleaner air may help children’s lungs grow more normally, although it cannot prove the clean-air zone caused every change.
Researchers followed more than 3,400 children in London and Luton for five years.
London children initially had slightly smaller lung capacity and higher nitrogen dioxide exposure than those in Luton.
After the Ultra Low Emission Zone began, London children’s lung capacity grew about 10 millilitres more per year on average.
After four years, average lung capacity was nearly identical in the two groups.
The study linked cleaner air with improved lung growth but did not prove the ULEZ alone caused every improvement.
- Who
- More than 3,400 children aged six to nine at the start of the study, living in London and Luton, were studied by researchers.
- What
- The study examined whether reducing traffic pollution through London’s Ultra Low Emission Zone was associated with better lung growth in children.
- When
- The children were followed for five years, beginning before the ULEZ started in April 2019; results were assessed over four years after its introduction.
- Where
- London and Luton, England.
- Why
- Researchers sought to determine whether cleaner urban air could improve children’s lung development.
- Study publication
- The Lancet
- Participants
- More than 3,400 children
- Age at enrollment
- Six to nine years
- Study duration
- Five years
- Lung growth difference
- London children’s lung capacity increased about 10 millilitres more per year on average
- Clinically impaired lung function in London
- Fell from 14% to 9% over four years
- Comparison city
- Luton, where no clean-air zone was introduced