Even "safe" levels of ozone air pollution may increase adolescents' risk of depression, a new study shows.
Researchers analyzed four years of mental health data from 213 adolescents, ages 9-13, in the San Francisco Bay area and compared it with air quality data for their home addresses.
Those who lived in areas with relatively higher ozone levels had significant increases in symptoms of depression over time, even though the ozone levels in their neighborhoods weren't higher than state or national limits.
The link between ozone pollution and depression symptoms such as chronic sadness or hopelessness, concentration problems, sleep disturbances and thoughts about suicide wasn't affected by the adolescents' sex, age, race, household income, parents' education or wealth of their neighborhoods, according to the study published online March 14 in the journal Developmental Psychology.
"It was surprising that the average level of ozone was fairly low even in the communities with relatively higher ozone exposure," and the study "really underscores the fact that even low levels of ozone exposure have potentially harmful effects," said lead researcher Erika Manczak, an assistant professor of psychology at the University of Denver.
Ozone and other types of air pollution can contribute to high levels of inflammation in the body, which has been linked to depression. Adolescents may be especially sensitive because they spend more time outdoors, the study authors suggested.
Ozone is created when various pollutants from vehicle exhaust, power plants and other sources react to sunlight. Higher ozone levels have been connected to various physical conditions, including asthma, respiratory viruses and premature death from respiratory causes.
This study is the first to show an association between ozone levels and depression in adolescents, according to the researchers. But it only found an association, and not a cause-and-effect link.
"I think our findings really speak to the importance of considering air pollution's impact on mental health in addition to physical health," Manczak said in a journal news release.
"I believe state and federal air quality standards should be stricter, and we should have tighter regulations on industries that contribute to pollution," Manczak said. "Our findings and other studies suggest that even low levels of ozone exposure can pose potentially serious risks to both physical and mental health."
There's more on teen depression at the U.S. National Institute of Mental Health.
SOURCE: Developmental Psychology, news release, March 14, 2022