Air pollution damages children’s brains, lowers IQ, says Unicef report
Air pollution causes irreversible damage to young children’s brains, says a new Unicef report.
Toxic air lowers children’s IQ and memory, affects their test scores and triggers neurological-behavioural problems such as anxiety, attention deficit hyperactivity disorder and development delays, according to the study.
The report estimates 17 million babies worldwide — 12 million of them in South Asia — live in areas that record pollution levels six times higher than the international safe limits of 20 microgram per cubic meter for PM10 and 10 microgram per cubic meter for PM2.5.
Pollution hurts children’s brains through several mechanisms, with infants before their first birthday being the most vulnerable.
“Most of the brain’s development happens in the first 1,000 days of life, which makes children vulnerable to damage by a smaller dosage of toxic chemicals ... Children also breathe more rapidly and are more likely to breathe through their mouths, which increase the amount of pollutants they inhale,” said Dr Krishnan Chugh, senior paediatric pulmonologist at Fortis Hospitals in Gurgaon.
Ultrafine particulates such as PM2.5 enter the bloodstream and travel to the brain. These damage the blood-brain barrier — a thin membrane that protects the brain from toxic substances — and cause neuro-inflammation, which is linked to Alzheimer’s and Parkinson’s diseases in elderly people, the Unicef report says.
The findings come amid a raging debate over the dangerous air quality in New Delhi. When pollution peaks in Delhi and northern India, as it did this November, air quality is 10 to 12 times above safe standards.
The level of PM2.5, a fine dust that causes and exacerbates respiratory and lung diseases, was 16 times more than the national standard and 40 times higher than the World Health Organization-prescribed grade after Diwali.
“Not only do pollutants harm babies’ developing lungs, they can permanently damage their developing brains and, thus, their future,” Unicef executive director Anthony Lake said.
He suggested that protecting children from foul air will help societies in terms of reduced healthcare costs, increased productivity and a safer environment.
Another major urban pollutant is magnetite nanoparticle, a magnetically-charged dust that enters the body through the gut and the olfactory nerve which controls the human sense of smell. The pollutant creates oxidative stress that causes neurodegenerative diseases.
Chemicals released from burning of fossil fuels such as coal, petrol and diesel are known to damage neural connections in the brain that are the foundation of learning and development.
These chemicals — called polycyclic aromatic hydrocarbons (PAHs) — are abundant in New Delhi’s air as the city has more than 10 million registered automobiles.
Children skipping classes in school because of frequent pollution-related infections and diseases compounds the damage to learning.
“Air pollution is associated with pneumonia, which kills 18 lakh children in India every year, and triggers asthma, bronchitis, and other throat and respiratory infections, forcing children to miss school and further limiting their learning and development potential,” said Dr Vinod K Paul, member Niti Aayog and professor of paediatrics at the All India Institute of Medical Sciences.
The risk begins in the womb. Exposure to air pollutants during pregnancy leads to toxins crossing the placenta and lowers birth weight and affect the developing brain of a foetus, with studies linking it to development delays at age three, psychological and behavioural problems, a four-point drop in IQ by age five, the Unicef report says.
“Indoor air pollution has gone down because people have switched to cleaner cooking fuels, but outdoor pollution is threatening to even out the gains. Parents must protect children from outdoor pollution and from tobacco smoke, cooking fumes and heating fires at home,” Dr Paul suggested.