Here's an interesting article that Austin Air posted on Mar 19, 2015 on their website.
It talks about a study done in Mexico City with children, and how compared to children living in less polluted areas, they had more toxins in their blood – causing damage to blood-brain barriers which can lead to serious neurological problems.
From the article:
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.