How toxic air is stunting children's IQ, fuelling asthma

Residents of Athiriver say that many industries and factories spew smoke at night.  [Gardy Chacha/Standard]

A new research featured in the abstract book of the World Conference on Lung Health (WCLH) has uncovered new harms presented by exposure to ambient air pollution.

The conference was hosted by the International Union Against Tuberculosis and Lung Disease (The Union), in Copenhagen, Denmark from November 18 to 21, 2025.    

The new harms include additional risks identified in childhood cognitive development and increased risk and symptomatic frequency of asthma.

New findings from the Kalinga Institute of Industrial Technology (KIIT), India, suggests a significant and close association between children’s intelligent quotient (IQ) development and exposure to air pollution.

The IQ is a total score derived from a set of standardised tests or subtests designed to assess human intelligence.

The study, which examined the impact of exposure to ambient air pollution due to particulate matter (particularly those with a diameter of 2.5 micrometres or 10 micrometres, known as PM2.5 and PM10 respectively) on the cognitive development of children aged 6 to 8 years in the state of Odisha, India.

The effects of exposure to ambient air pollution is well-documented in lung and cardiovascular health; however, this new research represents an early study into its potential to disrupt early cognitive development.

The KIIT’s study was conducted at two sites; one with high pollution (PM10>60 microgrammes per cubic metre & PM2.5>40 microgrammes per cubic metre, sample size=210), and one with low pollution (sample size=186) between July to December 2022.

Children residing for six years within a 1.5 km radius from air quality monitoring stations were assessed for their full-scale IQ, which included verbal and performance IQ.

 A regression model ensured that sociodemographic and environmental variables were also captured.

The study found that mean full-scale IQ in high-pollution areas was 80.33 (± 6.11 margin of error) compared to 98.12 (± 6.33) in low-pollution areas.

At the same time, children from high pollution areas had a verbal IQ of 81.60 (± 5.57) and a performance IQ of 79.02 (± 8.33), compared to 99.68 (± 6.60) and 96.55 (± 8.46) in low-pollution areas, respectively.

These findings indicate that long-term exposure to air pollution is closely linked to poorer cognitive development in children. Moreover, the regression model suggested that the age and weight of the child, poor kitchen ventilation, maternal education and family income were also associated with full-scale IQ.

“The burden of air pollution and climate change on health is one which sadly continues to grow. And, as with many other determinants of health, it is the world’s poorest who are the most affected,” said Professor Guy Marks, President of the International Union Against Tuberculosis and Lung Disease, while commenting on the research.

He added: “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.”

Also presented at WCLH, was a new study from the Centre Hospitalier et Universitaire de Pneumo-Phtisiologie (CNHUPPC) in Cotonou, Benin which has uncovered a link between air pollution and climate change with asthmatic conditions.

In Cotonou, where air pollution systemically exceeds World Health Organisation (WHO) thresholds for all pollutants, over 1/3 of a cohort of 730 asthmatic adolescents were found to have had respiratory events (‘asthma attacks’) during a 36-month follow-up period.

Those who showed frequent respiratory events had higher-levels of personal exposure to several pollutants, highlighting a direct link between air pollution and the frequency of events.

“Fine particulate air pollution remains very high in West Africa and poses a serious risk to the respiratory health of adolescents with asthma who are chronically exposed,” said Dr Attannon Arnauld Fiogbé, chest physician and clinical researcher, Centre Hospitalier et Universitaire de Pneumo-Phtisiologie.

De Arnauld added: “Strengthening responses by combining air quality alerts with therapeutic education could significantly improve the respiratory health of asthmatic adolescents in Cotonou.”

According to the WHO, approximately 7.5 million newly reported TB cases and 1.3 million TB-related deaths were documented globally in 2022. Air pollution (both household and ambient) resulted in an estimated 1.2 million premature deaths across the African Union in 2021.