Expectant mothers all wish for the same thing – healthy babies.

Unfortunately, air pollution is a hidden danger that can prevent those wishes from coming true. Unborn and newborn babies face grave risks from high levels of exposure to dirty air, including underdeveloped organs, premature births, low birthweight, and even infant mortality (1).

Threats to the developing brain

The most dangerous pollutants in the air are ultrafine particles (UFPs), those that are smaller than 0.1 microns and constitute about 90% all airborne pollutants. They pose the potential for great harm to a baby’s brain development because they can easily penetrate the blood-brain-barrier.

Infants are especially vulnerable to air pollution because (2) (3):

• their lungs are still developing
• they have faster breathing rates than adults, so they absorb more pollutants
• they spend time close to the ground where certain pollutants concentrate
• they are very active

But air pollution begins doing its damage even prior to birth.

Prenatal Exposure to air pollution

Studies have shown that damage to a baby’s brain development from air pollution can begin in the womb.
One Netherlands-based analysis linked greater exposure to air pollution during pregnancy to underdeveloped areas of the brain, including the nucleus accumbens, which helps guide motivational and emotional processes (4) (5).

A 2022 study led by researchers at the University of Washington showed that expectant mothers who were exposed to higher levels of nitrous dioxide (NO2) were more likely to give birth to babies that develop behavioral problems (6).

Another study, this one published in 2015, found a similar correlation between prenatal exposure to air pollution and behavioral issues in children. (7).

Higher the level of exposure in the womb to polycyclic aromatic hydrocarbons (PAHs - a group of chemicals that are the byproducts of burning coal, gasoline, trash, and other sources) the less white matter (nerve fibers that connect different brain regions) there was in the left hemisphere of a baby’s brain.

Lower amounts of white matter in that region are linked to behavioral problems.

A study at New York City’s Columbia University found that when exposed in the womb to high levels of PAHs, children are more likely to suffer from a variety of mental health issues, including depression, attention difficulties and increased stress, which has been identified as a precursor to other, more serious psychiatric disorders (8) (9).

A link to cognitive decline in children

In addition to the neurological disorders already discussed, numerous studies have revealed air pollution’s alarming impact on children’s cognition.

The children that had high levels of exposure to air pollution in the Netherlands study were also found to have underdeveloped hippocampi, which play a key function in learning and memory (10).

In the 2015 study on the exposure of expectant mothers to PAHs, the brains of the babies were scanned again at age 5. This time the scientists discovered decreased white matter in the prefrontal cortex, the area of the brain tied to concentration, reasoning, judgment, and problem-solving.

The University of Washington study found that children two to four years of age who were exposed to higher levels of PM2.5 (pollution particles that are 2.5 microns in diameter or smaller) than their peers had lower cognitive performances.

Decreasing the risks of stunted brain development

No matter where you live, there are steps you can take to lessen a baby’s exposure to harmful airborne particles, helping to ensure the baby’s brain development is not impeded.

Limit or eliminate indoor sources of pollutants. Be vigilant of outdoor air pollution seeping inside especially during morning and evening rush hours. Low-cost indoor air quality monitors are available to help you track the air quality inside your residence.

Monitor your local outdoor air quality and when pollution particle levels are high, close windows and doors and restrict outdoor activities.

One of the most important steps you can take is to use a high-performance air purifier. This is particularly critical in a baby’s nursery. There are compact personal air purifiers available that direct clean air right to a baby’s breathing zone.

The takeaway

Exposure to poor air quality affects our brain functions from the womb and all the way into old age.

The findings of a recent study hammered that point home when it showed a strong link between childhood air pollution exposure and the early development of Alzheimer’s disease symptoms (11).

The research reviewed the autopsies of children in Mexico City, one of the world’s most polluted metropolitan areas.

Compared with control subjects from areas with better air quality, the young people that had been living in Mexico City displayed numerous signs indicating accelerated progression of Alzheimer’s disease including an imbalance in certain genes, neurovascular damage, neuroinflammation, and brain lesions.

The researchers concluded that more attention must be paid to the devastating effects that air pollution creates on the brain development of babies and young people.

The study’s authors called for the prioritization of air pollution policies and regulations, and the targeting of neuroprotective interventions in the early years in a person’s life, especially those who are exposed to high levels of pollutants in the air they breathe.

Air pollution can be controlled. So can the devastating impacts air pollution has on brain development.