Air pollution could impact the brain development of children and not just damage their lungs, new research has shown.
Long term exposure to poor air quality has been closely linked to poor cognitive development in an evaluation of the impact on children aged 6 to 8 in the state of Odisha, India.
Findings from the Kalinga Institute of Industrial Technology (KIIT) were shared at the World Lung Health conference in Copenhagen, and showed children living in highly polluted areas scored 20 IQ points lower than others living in cleaner environments.
Scientists examined the impact of exposure to ambient air pollution due to particulate matter.
The research looked at the damage of PM2.5 pollutants on children, which are tiny particles from sources like dust, soot, and smoke.
While the effects of exposure to ambient air pollution is well-documented in lung and cardiovascular health; this latest research gleaned from a study in December 2022 showed potential to disrupt early cognitive development.
Children under six living within 1.5km of an air quality monitoring station were assessed in a verbal and performance IQ test.
A verbal IQ test measures abilities like vocabulary, comprehension, and verbal reasoning through written or spoken questions, while a performance IQ test assesses non-verbal skills like spatial processing, visual-motor co-ordination, and problem-solving through practical, hands-on tasks.
“The burden of air pollution and climate change on health is one which sadly continues to grow,” said Professor Guy Marks, president of the International Union Against Tuberculosis and Lung Disease.
“The impact of air pollution on childhood development is an unacceptable consequence of climate change. New strategies are urgently needed globally to ensure no one’s future is limited simply because of the air they breathe.”
Lower IQ
Results of the Indian study showed full-scale IQ in high-pollution areas was 80.33 compared to 98.12 in low-pollution areas. Meanwhile, children from high pollution areas had a verbal IQ of 81.60 and a performance IQ of 79.02, compared to 99.68 and 96.55 in low-pollution areas, respectively.
The findings indicate long-term exposure to air pollution is closely linked to poorer cognitive development in children.
Age and weight of the child, poor kitchen ventilation, maternal education, and family income were also associated with full-scale IQ.
On Wednesday, PM2.5 concentration in Dubai was 4.8 times the World Health Organisation annual guideline value, a common occurrence in the UAE.
The country is vulnerable to an increase in PM concentrations, driven by regional dust storms and industrial emissions.
Dubai was recently named among the top 10 most polluted cities in the world by air purifier company IQAir, that monitors air quality of cities around the world.
While doctors in the UAE said it can be difficult to cite air pollution with delayed cognitive development in children, the study should offer a gateway into more local research.
“Lots of people are moving to Dubai and don't have any any respiratory issues like chronic coughs, asthma or these kind of things,” said Dr Gulben Efes, a specialist in paediatrics at NMC Marina Medical Center.
“But after they move here, they start to have chronic cough or asthma, wheezing and respiratory problems.
“For the population living in polluted areas, there are long term effects, but in a day to day basis, we cannot understand the full impact on IQ. Potentially it could be an unreported area.”
In her work as a pediatrician, Dr Efes said autism, attention deficit hyperactivity disorder and other behavioural issues were the most common development issues diagnosed in Dubai children.
“In some research, we have seen pollution make structural alterations in children's brains, but in some other research it creates functional problems,” she said.
“There's not a strong conclusion, but many studies are showing some impact on the neurological development of children.
“Some researchers have found lead or other kind of heavy metals in air pollutants may cross the brain barrier, which can have an impact, especially at very early developmental ages like prenatal or early childhood stages.
“This can cause attention deficit, concentration problems or autism, but we cannot say this 100 per cent.”
A 2017 report by Unicef found air pollution potentially affects children’s brains through several mechanisms. It stated the dosage of toxic chemicals required to damage the growing brain in the first stages of life was much lower than that which would cause damage to an adult brain.
The international children’s charity said 17 million babies living in some of the world’s most polluted regions were most at risk, with 12 million in south Asia.
Fuelling concern
In separate research by the University of Eastern Finland, scientists explored the impact of diesel exhaust fumes on brain health.
The findings, published in Environment International, shed light on how traffic-related air pollution could contribute to brain inflammation and neurodegenerative diseases.
Scientists found diesel exhaust particles can disturb the function of human brain immune cells, known as microglia.
Results showed particles from engines with older emission control technology caused extensive transcriptional and functional changes in microglia, while particles from renewable diesel used in modern Euro 6–compliant cars had only minor effects.
“Because these patterns appear across different countries and populations, the findings fit well with what previous research has indicated,” said Dr Mohammed Harriss, a pulmonologist at the Medcare Royal Specialty Hospital, Dubai.
“What stands out is not surprise, but the consistency across studies, all pointing toward a link between pollution exposure and early cognitive outcomes, even when exposure levels are relatively low.
"The concerns go beyond breathing difficulties. Different studies have shown that pollution can influence several developmental areas, including attention, memory, executive function, and general intellectual skills.
Taking action
The UAE's National Air Quality Agenda 2031 aims to bring together federal and local government bodies and the private sector to boost air quality.
Abu Dhabi and Dubai have also introduced their own strategies to curb air pollution, with the combined effort reaping rewards.
Levels of PM2.5 dropped significantly in a year, according to a report that ranks countries by air quality issued in March.
While concentrations of the smallest type of particulate matter remain above levels recommended by the World Health Organisation (WHO), the 2024 World Air Quality Report from Swiss company IQAir reveals that they have fallen by more than a fifth.
As a result of the improvement, the UAE is now ranked 17th globally in terms of countries with the worst air pollution, an improvement of 10 places since the 2023 report, which focuses on levels of PM2.5 or particulate matter up to 2.5 micrometres in diameter.
