A new study suggests that breathing polluted air not only damages the lungs but may also increase the risk of developing brain tumors.

Scientists examined a range of air pollutants commonly associated with traffic, such as nitrogen dioxide and ultrafine particles often found in urban environments.

The study, published in the journal Neurology, found that people exposed to a type of pollution were more likely to develop a non-cancerous brain tumor called meningioma.

Study author Dr. Ola Hudfeldt, from the Danish Cancer Institute in Copenhagen, said that various types of air pollution have been shown to have negative health effects, and ultrafine particles are small enough to cross the blood-brain barrier and potentially directly affect brain tissue.

He said that research suggests that prolonged exposure to air pollution from traffic and other sources may play a role in the development of meningiomas.