Air Pollution is Linked to Adverse Brain Development in Young Children


Infants’ brains are negatively affected by air pollution, according to a study which has documented the effects of children’s exposure to air pollution from conception to the age of eight-and-a-half years for the first time.   

Tracking 3,515 children aged 9-12, the study found an association between exposure to air pollutants in the womb and their early years of life to alterations in white matter structural connectivity in the brain.

“One of the important conclusions of this study is that the infant’s brain is particularly susceptible to the effects of air pollution not only during pregnancy, as has been shown in earlier studies, but also during childhood,” said Anne-Marie Binter, Barcelona Institute for Global Health (ISGlobal) researcher and first author of the study, which was published in the journal Environmental Pollution.

White matter is what ensures interconnectivity between different areas of the brain, making up the tissue through which messages are passed from region to region within the central nervous system.

Due to its role as a “neurological bridge”, abnormal development of white matter can play an outsized role in learning and brain functions, and has been linked with psychiatric disorders including anxiety, depressive symptoms and autism spectrum disorders. 

The study also found a link between specific exposure to fine particulate matter (PM2.5) and the volume of the putamen, a brain structure involved in motor function. Beyond its effects on children’s developmental health, PM2.5 is estimated to be responsible for about 4.2 million deaths annually according to researchers at McGill University.

“A larger putamen has been associated with certain psychiatric disorders like schizophrenia, autism spectrum disorders, and obsessive-compulsive spectrum disorders,” said Binter.

While previous studies have been directed at the question of the effects of air-pollutants on childhood brain development, none have been as granular in their

“The novel aspect of the present study is that it identified periods of susceptibility to air pollution,” Binter explained. “We measured exposure using a finer time scale by analysing the data on a month-by-month basis, unlike previous studies in which data was analysed for trimesters of pregnancy or childhood years.”

The study is the latest addition to an ever-growing mountain of evidence documenting the negative effects of air pollutants on human health.

According to the World Health Organization (WHO), 99% of all people breathe air that exceeds WHO air quality limits, and threatens their health. Earlier this year, The Lancet estimated the overall death toll of “modern” air pollution sources to be nine million, making air pollution the world’s largest environmental risk factor for disease and premature death.

 “We should follow up and continue to measure the same parameters in this cohort to investigate the possible long-term effects on the brain of exposure to air pollution,” concludes Mònica Guxens, ISGlobal researcher and last author of the study.


Image Credits: Vicente Zambrano González, Barcelona City Council.

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