Exposure to polluted air makes children more susceptible to mental disorders such as anxiety and suicide, according to a new study.

Researchers at the Cincinnati Children's Hospital said short-term exposure to smoking and vapors from traffic and industry could lead to a sharp rise in mental illness as well, within one to two days.

The study found that children living in poor neighborhoods may be more susceptible to the effects of air pollution than other children.

This is the first study to show an association between levels of outdoor air pollution per day and increased symptoms of mental disorders, such as anxiety and suicide in children.

According to one of the doctors in the study, they need more research to confirm these findings, but the research could lead to new preventive strategies for children with symptoms associated with mental disorder.

The study used brain scans to show that children living near a busy road have higher levels of minocetol in their brains, a sign of anxiety.

"These studies contribute to a growing body of evidence that exposure to air pollution during early life and childhood may contribute to depression, anxiety and other mental health problems in adolescence," said Dr. Patrick Ryan, co-researcher.

More than 80% of the world's urban population is thought to breathe unsafe levels of air pollution.