A new UK study has found that air pollution is slowing the lung growth of children, with effects persisting into early adulthood. Researchers tracked the lung function of over 5,000 individuals born in and around Bristol in the 1990s, assessing their health from birth and testing their lungs at ages 8, 15, and 24 years.
Impact on Lung Development
Lead author Prof Ann Hansell of the University of Leicester stated, "Much of the evidence on health effects of air pollution relates to adults or pregnancy, but we think it’s highly plausible it has impacts on growth and development of children." She added that those whose lungs do not reach maximum potential in childhood may be more vulnerable to respiratory diseases in later life due to lower reserve, and are also at greater risk for poorer health generally. Low lung function in adults is associated with a risk of heart disease comparable to high cholesterol.
Study Methodology
Dr Katie Eminson, also of the University of Leicester and first author, explained that lung function was measured using spirometry by trained technicians. Participants took a deep breath and blew out as hard and fast as possible into a mouthpiece, measuring both air volume and speed. The researchers calculated air pollution exposure during each trimester of pregnancy and for each year of early childhood, including particulate matter and nitrogen dioxide from diesel cars and fossil gas boilers.
"We spent literally years creating the particulate air pollution exposure estimates in pregnancy and early life, including sourcing road traffic data from Bristol city council that are not available in the national database," said Hansell.
Key Findings
After accounting for factors like premature birth, breastfeeding, parental smoking, and home conditions, the team found that breathing more air pollution during pregnancy, infancy, and early childhood can slow lung development through early adulthood. The greatest impact occurred during adolescence, when lung growth accelerates. An earlier study in east London found that average nine-year-olds had lungs 90 to 100 millilitres smaller than expected, roughly the volume of two hen's eggs. Conversely, studies in Sweden showed that lung growth improved when air quality increased, suggesting that reductions in air pollution may allow lung growth to return closer to normal rates.
Long-Term Implications
Eminson concluded, "While the effects in individual children are small and unlikely to have immediate clinical consequences, they shouldn’t be dismissed. Because lung function tends to track from childhood into adulthood, small differences early in life may have implications for long-term health. This reinforces the importance of reducing exposures and protecting children’s environments."
