The higher the level of particulates in the air, a new study shows, the greater the indications of psychological distress.

"This is really setting out a new trajectory around the health effects of air pollution," says Anjum Hajat, an assistant professor of epidemiology in the School of Public Health at the University of Washington.

"The effects of air pollution on cardiovascular health and lung diseases like asthma are well established, but this area of brain health is a newer area of research,"