Children at higher risk due to air toxins
Airborne ultrafine particulate matter from fuel emissions were linked to increased risk of brain tumours by a study, which put the spotlight on the extrapulmonary damage to health from airborne toxins. Everyone is vulnerable to air pollution, but younger children are at the most at risk. With every breath, children take in more air per unit of body weight than adults.
Airborne ultrafine particulate matter (PM <0.1) from fuel emissions were linked this week to increased risk of brain tumours by a large study from Canada, which once again put the spotlight on the extrapulmonary damage to health from airborne toxins.
The World Health Organisation (WHO) annual mean cut-off for fine particulate matter (PM2.5) is <10 μg/m3, but Delhi’s annual mean was 115μg/m3 in 2018, and 97.7μg/m3 till November 14 this year, according to Central Pollution Control Board. The brain is the biggest oxygen guzzler, consuming 20% of the total body oxygen while accounting for just 2% of body weight. This makes it more susceptible to the air-borne toxins.
Everyone is vulnerable to air pollution, but younger children are at the most at risk. With every breath, children take in more air per unit of body weight than adults. They breathe faster than adults and inhale two to three times more pollutants than older people, inhaling far more toxins per unit of body weight than adults. Compared to an adult who inhales between 12 and 18 times a minute, a newborn breathes in 30 to 40 times a minute, and a toddler 20 to 30 times.
IRREVERSIBLE DAMAGE
Children often do not show visible signs of health damage, which accrues over time and becomes irreversible when they get older. “All of us have a reserve that stops us from becoming breathless when lung capacity falls to some extent. But when that reserve goes as you age, the chances of getting respiratory problem become higher. So it will cause problems in later life, it may not cause that much of a problem in the younger age group,” said Dr Randeep Guleria, Randeep Guleria, director, All India Institute of Medical Sciences, and head of the department of pulmonary medicine and sleep disorders.
The blood-brain barrier is not fully formed in children, which allows fine and ultrafine particles to cross the blood-brain barrier(a delicate membrane that protects the brain from toxins) to cause neuro-inflammation and damages the brain cells. This lowers a child’s thinking and cognitive ability and affects intellectual development over time.
In older adults, the breakdown of the blood-brain barrier has been strongly linked degenerative brain diseases, such as Alzheimer’s and Parkinson’s diseases. Experts say brain damage in young children begins at doses much lower than those that damage an adult brain.
“Studies have found associations directly between air pollution exposure and cognitive outcomes, including reduced verbal and nonverbal IQ, memory, test scores and grade-point averages among school children, as well as other neurological behavioural problems,”according to the Unicef’s report, Danger in the air: How air pollution can affect brain development in young children.
Then there are the ripple effects of missing school from frequent illnesses, schools being shut, and restricted outdoor activity, all of which further limits children reaching their full learning and developmental potential.
WOMB NOT SAFE
The damage begins in the womb. A mother’s exposure to toxic air during pregnancy reduces her unborn child’s heart rate variability, which affects stress response and is a known risk factor for heart disease, asthma, allergies, and mood and behavioural disorders, according to a study published in Environmental Health Perspectives in October.
Air pollutants inhaled during pregnancy cross the placenta to produce potential lifelong effects, such as low birth weight, developmental delays at age three, and psychological and behavioural problems later in childhood, including symptoms of attention deficit hyperactivity disorder (ADHD), anxiety and depression. One study found a four-point drop in IQ by the age of 5 among a sample of children exposed in utero to toxic air pollution.
A new study led by the Barcelona Institute for Global Health (ISGlobal) this week found a link between air pollution and changes in the corpus callosum, a region of the brain associated with neurodevelopmental disorders such as ADHD and autism spectrum disorder (ASD). Each 7 μg/m3 rise in PM2.5 levels was associated with a nearly 5% fall in the mean volume of the corpus callosum, according to the study in in Environmental Research.
PROTECTING KIDS
A nutritious diet high in protein and micronutrients from fruits, vegetables, nuts and seeds help build immunity and minimise damage, including offering protection from infections such as seasonal influenza and pneumonia.
Vaccinating children with the pneumococcal vaccine and the flu vaccine gives additional protection against infection, as does exclusivebreastfeeding(withno other fluids or solids) for six months and then continued along with solid foods for two years or more.
Policy changes, like the adoption of unleaded petrol to protect children from neural and brain damage, can reduce the potential scale and impact of air pollutants, as can reducing the use of fossil fuels by opting for cleaner, renewable sources of energy, including the use of solar, wind and thermal power.
Improved and affordable public transportation, better waste management, smart urban planning with adequate trees and green areas within neighbourhoods help improve local air quality while offering children a space to play.