A study recently released by University of Rochester researchers indicates that air pollution exposure may have a negative impact on mental health and could possibly play a role in schizophrenia and autism. The university's study was published in the journal Environmental Health Perspectives.

The researchers found that air pollution causes inflammation in the brains of newly born mice, which damages the development of “white matter.” The same parts of the brain are known to be affected in humans exhibiting autism and schizophrenia traits.

The university researchers say that when mice are exposed to extra fine particle air pollution in the first few weeks of life, they developed neurological abnormalities similar to those seen in humans with the two health disorders. The abnormalities were mostly found in male mice, which also corresponds to the high numbers of men and boys diagnosed with both schizophrenia and autism.

The research concurs with a 2013 study published in JAMA Psychiatry that also drew a link between air pollution and autism. That study, by researchers at the University of Southern California and the University of California, found that children who lived in areas with high levels of traffic pollution were three times more likely to be diagnosed with the neurodevelopmental disorder.

But the University of Rochester research is the first to link more mental-health disorders to air pollution.

“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,” said Deborah Cory-Slechta, professor of Environmental Medicine at the university.

The Rochester study found that the brain's lateral ventricles, which are cavities filled with fluid to protect it from trauma, were three times their normal size. Similar dilation of the lateral ventricles has also been found in humans with autism and schizophrenia. The study also found that mice breathing polluted air also had high levels of glutamate, a neurotransmitter, in the brain.

Glutamate, is one of the most abundant chemical messengers in the brain. It plays a key role in learning and memory. Moreover, it serves as a source of energy for the brain cells when their regular energy supplier, glucose, is lacking. But excess glutamate can damage and even kill neurons by generating free radicals in the cells that it over-excites. High levels of glutamate are also found in individuals suffering from these same two disorders.

The atmospheric contamination created by the researchers mimics what might typically be present at peak rush-hour traffic in a moderately-sized U.S. metropolitan area. The mice were exposed to air polluted with extremely fine particles for four hours for eight days during the first two weeks after birth. The finest air-pollution particles are believed to have the greatest health impact, according to the researchers.

Cory-Slechta, the study's lead researcher told Al Jazeera America that in their studies they used the smallest air particles.

“Basically, we pulled them in from the outside and we concentrate them so it's not the Rochester level of air pollution,” she said. “It would be more consistent of what you would have if you were driving through Los Angeles or Atlanta on the freeways.”

Schizophrenia is a mental disorder characterized by abnormal social behavior and failure to discern what is real. Symptoms typically include false beliefs, auditory hallucinations, unclear thinking, inactivity, and reduced social engagement and emotional expression. While the disorder is thought to mainly affect the ability to think, it also contributes to chronic problems with behavior and emotion. It is diagnosed based on observed behavior by psychiatric professionals and a patient's reported experiences. Symptoms often begin in young adulthood. Researchers say that about 1 in 200 people are affected with the disease in their lifetime. Sufferers of schizophrenia often don't adjust well to society and have problems with long-term unemployment, poverty, and homelessness. Life expectancy of those with the schizophrenia is 12 to 15 years less than those without.

Autism is a neurodevelopmental disorder characterized by impaired social interaction; verbal and non-verbal communication; and restricted, repetitive behavior, with symptoms apparent in a child's first years. The disease affects information processing in the brain by altering how nerve cells and their synapses connect and organize. It occurs about four times more often in boys than girls. The Centers for Disease Control report that 1.5 percent of children in the United States now suffer from autism. This is a 30 percent increase from 2012.

Nearly half of the 300 million people in the U.S. live in areas where the air quality has been deemed unhealthy by the American Lung Association. And although air pollution has worsened between 2010 and 2012, it is much cleaner than it was a decade ago when autism diagnoses were at their peak. After rates surged in the 1990s, they peaked in 2004 and have held steady since, according to the journal BMJ Open.

Both ozone and particle pollution are dangerous to human health. High levels of ozone can create respiratory harm, including asthma and worsened COPD (chronic obstructive pulmonary disease). It can also contribute to or cause cardiovascular disease, harm to the central nervous system and cause developmental harm in children. Fine particle pollution, the contamination in the Rochester study, can cause cancer, cardiovascular disease, pulmonary disease, and reproductive and developmental harm.

Cory-Slechta, lead researcher, says her team's discovery doesn't mean that air pollution is solely to blame for these two diseases.

"I never use the word 'causes,'" she told USA Today. "I try to make people understand it's the interaction of all these risk factors in your life, over your lifespan, that come together."

She says that governments should take the study’s findings into account when weighing air-quality standards.

“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," she said.