In April 2019, London introduced the Ultra Low Emission Zone (ULEZ) to tackle severe traffic-related air pollution in the city center.
Five years of data from this real-world experiment now suggests that the ULEZ, along with the earlier Toxicity Charge, significantly benefited the lung health of children living in central London.
Evidence That Clean-Air Policies Can Protect Children’s Lungs
The findings offer encouraging evidence for similar clean-air policies worldwide. Researchers say the study provides the first evidence linking improved air quality after the introduction of a clean-air zone with healthier lung development in children.
They recommend that policymakers around the world consider implementing clean-air zones more quickly to protect children’s respiratory health.
Research shows that exposure to traffic-related air pollution can increase the risk of serious lung conditions, including cancer, as well as premature death.
Air Pollution Can Hinder Children’s Lung Development
For children and teenagers, prolonged exposure is particularly concerning because it can interfere with normal lung development. This may increase their likelihood of developing asthma, chronic obstructive pulmonary disease, cardiometabolic problems, and experiencing a shorter lifespan later in life.
Official figures indicate that since the introduction of the ULEZ, roadside nitrogen dioxide levels—a major pollutant produced by heavy traffic—have dropped by 54% in central London and 27% across the city.
However, until recently, there has been little concrete evidence showing how much policies such as London’s ULEZ actually improve residents’ health. This lack of data has fueled criticism from people concerned about the financial burden the scheme places on drivers.
The issue became even more controversial after the ULEZ was expanded to cover the whole of Greater London.
Researchers from several UK institutions assessed the lung function and development of 3,414 children who were between six and nine years old when the study began.
About half of the participants lived in central London, while the others lived roughly 56 kilometers (35 miles) away in Luton, a busy industrial town that had not implemented a clean air zone.
Researchers Track Children’s Lung Function Over Time
During annual school assessments, the researchers evaluated the children’s lung function by measuring how much air they could forcefully exhale in one second. This is a standard medical method for determining lung performance and monitoring lung development in children.
With a population of about 225,000, Luton is naturally different from London as a place for children to grow up.
However, researchers designed the study on the assumption that children in both locations followed broadly similar lifestyles, with the main differences being their exposure to air pollution and the introduction of the ULEZ in London.
ULEZ Helps Close the Lung Development Gap Between London and Luton Children
During the first year of the study, before introducing the ULEZ in central London, researchers found that London children had slower average lung growth than children in Luton.
Their estimated yearly exposure to nitrogen dioxide (NO₂) was also 18.95 μg/m³ higher than that of children in Luton.
However, after the ULEZ was introduced, the gap began to narrow. London children experienced lung function growth that was, on average, 10 mL per year faster than that of their peers in Luton.
At the same time, nitrogen dioxide (NO₂) levels in central London fell by an average of 3.77 μg/m³ each year, compared with a smaller decline of 1.77 μg/m³ annually in Luton.
Strong Evidence Links ULEZ to Better Lung Health
The likelihood that both the reduction in pollution and the improvement in lung growth happened purely by chance is extremely low, providing strong evidence that the ULEZ played a significant role.
Four years after introducing the ULEZ, researchers found that London children had lung function levels comparable to those of children in Luton.
Researchers also found that as air pollution levels declined in central London, the proportion of children with clinically impaired lung function decreased from 14% before the ULEZ was introduced to just 9% five years later.
Parents, children, and teachers also reported noticeable improvements, describing cleaner air, less traffic congestion, and fewer problems with asthma.
As air quality improved, children in London were four times more likely than those in Luton to begin walking or cycling to school.
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Read the Original Article on: Science Alert
