Air pollution made up of carbon particles produced by burned fuel from power plants, factories, and cars raises obvious health concerns surrounding respiratory function, however, developing research suggests it could also hinder neurological development.  A recent study funded by the National Institute of Environmental Health Sciences has revealed that harmful changes in the brain caused by air pollution exposure at a young age can result in autism and/or schizophrenia.

"Our findings add to the growing body of evidence that air pollution may play a role in autism, as well as in other neurodevelopmental disorders," Dr. Deborah Cory-Slechta, lead researcher and professor of Environmental Medicine at the University of Rochester, said in a statement. "I think these findings are going to raise new questions about whether the current regulatory standards for air quality are sufficient to protect our children.”

Cory-Slechta and her colleagues conducted three sets of experiments involving mice that were in their first two week of life, a critical time for neurological development. For four hours each day over two four-day periods, the mice were exposed to levels of air pollution consistent with mid-sized cities in the U.S. during rush hour. The research team examined the brains of mice 24 hours, 40 days, and 270 days after their final exposure to air pollution.

After 24 hours from final exposure to air pollution, researchers noted that lateral ventricles, chambers on each side of the brain containing cerebrospinal fluid, were two-to-three times larger than their normal size on top of widespread inflammation throughout the brain. Brains of mice also showed elevated levels of glutamate, a neurotransmitter that is found in humans suffering from autism and schizophrenia. The changes to the brain were also observed at 40 and 270 days after the final exposure, suggesting the neurological impairment was permanent.  

"When we looked closely at the ventricles, we could see that the white matter that normally surrounds them hadn't fully developed," Cory-Slechta added. "It appears that inflammation had damaged those brain cells and prevented that region of the brain from developing, and the ventricles simply expanded to fill the space."

Cory-Slechta also noted that previous research examining air pollution’s hazardous effect on the human body tends to focus on the different sizes of pollution particles. For example, larger particles that are regulated by Environmental Protection Agency (EPA) are actually less threatening because they are usual exhaled from the body while coughing. On the other hand, smaller particles, also known as ultrafine, that are not regulated by the EPA pose more of a threat because they are small enough to be absorbed into the bloodstream when inhaled, causing trouble throughout the human body.

Source: Allen J, Liu X, Cory-Slechta D. Early Postnatal Exposure to Ultrafine Particulate Matter Air Pollution: Persistent Ventriculomegaly, Neurochemical Disruption, and Glial Activation Preferentially in Male Mice. Environmental Health Perspectives. 2014.