Air Pollution Linked to Lower IQs in Children

There is alarming new evidence that air pollution can negatively affect IQ in children. Chronic exposure to air pollution has been known to cause neuroinflammation, or swelling of the brain tissue, for some time now. The implications of this include an increase in strokes, Alzheimer’s and Parkinson’s diseases. Knowing this, researchers from different parts of the globe have studied the impact of air pollution, such as ozone and airborne particulates, on the brains of children.

One team, made up of researchers from the US, Mexico, and Canada began their research in Mexico City because it is a megacity. Megacities are defined as municipalities with a population of over ten million people. Due to the high density of people, they typically have higher levels of ambient pollution. Children living in such cities have been found to have a higher frequency of neuroinflammation than the general population of children. The researchers concluded that the children who were free of genetic risks for neurological or cognitive difficulties showed deficiencies with performing cognitive tasks – implying that their brain function was not as it should be and pollution may have been the cause. This study, first published in 2008, was groundbreaking for being interdisciplinary and showing that the environment can impact brain function.

These findings prompted the team to continue studying children in the Mexico City Metropolitan Area (MCMA). They compared serum and cerebrospinal fluid (CSF) from children living in MCMA to kids of the same gender, age, socioeconomic backgrounds, and educational levels living in less populated areas. They also took into consideration the amount of school completed by the parents of the children. As suspected, the children living in the more populated, and thus more polluted, area had more toxins in their blood – causing damage to blood-brain barriers which can lead to serious neurological problems.

When particulate matter and metals are inhaled/swallow, they do major damage. Neuroinflammation isn’t the only concern with regard to air pollution and children’s brains. Oxidative stress, which is thought to lead to conditions such as cancer and degenerative neurological disorders like multiple sclerosis, is also associated with exposure to contaminated air. Most alarmingly, the children tested were actually producing autoantibodies against proteins in their brain – almost self-destructing.

In their third study about the harm air pollution can have on young brains – also published in the Journal of Alzheimer’s Disease – they took a look at the apolipoprotein E (APOE) 4 allele. It is the most common genetic risk for Alzeimer’s. The APOE allele is also responsible for how the brain responds to air pollution. They again tested healthy children from the same polluted area to see if APOE 4 – catalyzed by higher rates of air pollution – impacted their cognitive abilities, sense of smell, and IQ. Fifty children were selected – 22 with APOE 4 and 28 with APOE 3. The children with APOE 4 had lower attention spans, weaker short-term memory, and their scores on multiple IQ tests were below average. They also had trouble identifying common smells – like soap. Lower IQ scores, and all of the problems which can be associated with it, aren’t the only concern. Based on these findings, the researchers believe that all people with APOE 4 living in polluted places may be at a higher risk for developing early on-set Alzeimer’s.

The results from another study, this one conducted by a team in Barcelona, supports the claim that air pollution can be harmful to the cognitive abilities of children. Air pollution spikes during periods of heavy traffic – which typically coincide with the school day – as such, they compared 2,715 elementary students who attended school in areas which are located near busy roads to those in low traffic areas. They tested the amounts of pollution in the air inside the schools as well as in outer play areas before comparing the cognitive development of the two groups of children over the course of a school year. Imagine, if you will, the difference between a child at the beginning of a school year versus that same student at the end of the year – general speaking, even casual observers can see that much developmental progress has been made. Children who were in the schools near heavy traffic zones showed lower amounts of progress when compared to their counterparts in areas with less traffic.

The more we learn about the dangers of air pollution in our world, the more we realize it affects not only our respiratory health but in fact every aspect of our health and wellbeing. A silver lining to these studies is that they validate efforts to protect the environment while shedding light on opportunities for neuroprotection. Classifying air pollution as a neurotoxin may be the first step to motivate people and governments toward making greater strides to cleaning up our environment and providing everyone with a safer place to live. We may not be able to control the air quality everywhere, but we can do our best to make our homes, workplaces, and schools safer places. Enlisting the help of medical-grade air purifiers can be an affordable way to do gain some peace of mind with respect to improving your indoor air quality.