Exposure to air pollution in childhood linked to poorer health in late adolescence

Young people in the UK who lived in polluted areas during their early years are more likely to report worse general health than their peers at age 17, according to new UCL research.

The study, published today in Scientific Reports, reveals that teens from ethnic minority backgrounds and deprived neighbourhoods were particularly at risk of being exposed to high levels of air pollution during childhood, with potential long-term impacts on their health.

What the researchers looked at

Academics from the UCL Centre for Longitudinal Studies analysed data from more than 9,000 young people born in 2000-02 who are taking part in the Millennium Cohort Study.

They examined study participants’ home addresses taken from birth to age 17 with linked geospatial data showing the level of air quality in a 200-metre area around their postcodes. The researchers then looked at young people’s reports on their general health at age 17.

Three air pollutants were considered in the study. Particulate matter (PM₁₀) and fine particulate matter (PM_2.5), which are made up from various chemical compounds and materials, some of which are toxic; and nitrogen dioxide, which is a gas produced mostly by cars, buses and lorries.

What the study found

Adolescents in the UK who lived in areas with higher levels of air pollution during childhood were at greater risk of reporting worse health in late adolescence than their peers living in less polluted neighbourhoods.

The research found that the early years were a particularly sensitive period for children’s health. Those exposed to higher levels of air pollution at ages 2-4 had a 15-30% higher risk of reporting worse health at age 17. At ages 5-7 the association was weaker with a 14-16% higher risk. Associations were more robust for PM₁₀ and PM_2.5.

The study’s findings showed stark inequalities in children’s exposure to air pollution. Individuals from ethnic minority families and disadvantaged homes were much more likely to grow up in neighbourhoods with poor air quality. For example, non-white children were exposed to 51% higher nitrogen dioxide levels than their white counterparts during their early years.

The impact of air pollution on general health was comparable across ethnic groups. However, the researchers added that as ethnic minority children tended to be exposed to poorer air quality, a higher percentage would most likely suffer from worse general health in adolescence.

In a separate analysis, the research team examined participants’ linked hospital records – currently available only in England – to provide an objective marker of their general health. Unlike the main results, exposure to air pollution in childhood was not clearly associated with a higher number of hospital admissions.

Study implications

Lead author, Dr Gergo Baranyi (UCL Centre for Longitudinal Studies) said: “Our new study adds vital new evidence about the importance of the early years for children’s health and development. Using nationally representative information with linked geodata, our findings confirm that there is a sensitive window when children are more vulnerable to air pollution with long lasting impacts on their general health into late adolescence.

“Emerging research shows that children living in polluted areas are at higher risk of respiratory diseases, high blood pressure, obesity, mental health problems and lower cognitive function.”

Lead author, Dr Gergo Baranyi

“Emerging research shows that children living in polluted areas are at higher risk of respiratory diseases, high blood pressure, obesity, mental health problems and lower cognitive function. For disadvantaged and ethnic minority children, the impact of environmental hazards might be particularly detrimental.

“Despite air pollution levels dropping significantly in the UK in the past 20 years, we found that disadvantaged and ethnic minority children were exposed to much higher levels of pollution. These inequalities persisted across their childhood. Long-term exposure to air pollution can lead to developing chronic conditions in childhood which may harm their health across the whole life course.

“Policies reducing concentrations of air pollution below recognised World Health Organisation guideline limits may have long-term benefits, especially for children whose developmental years are such a critical period. High pollution levels in disadvantaged areas should be especially targeted to remedy evident socioeconomic inequalities in air quality and general health.”

Media coverage of this research

The Guardian – Early air pollution exposure affects health in adolescence, study finds

Further information

‘The relationship between early life course air pollution and general health in adolescence in the United Kingdom’ by Gergo Baranyi, Katie Harron, Youchen Shen, Kees de Hoogh and Emla Fitzsimons is available on the Scientific Reports website.