Air pollution could trigger depression in children, study warns

DENVER — Air pollution could trigger depression in children, suggests a new study. Scientists at the University of Denver say exposure to ozone from air pollution has been linked to an increase in depressive symptoms among adolescents, even in areas that meet air quality standards.

Ozone is a gas that is produced when various pollutants from motor vehicle exhaust, power plants and other sources react to sunlight. Higher ozone levels have been previously linked to several physical ailments, including asthma, respiratory viruses and premature death from respiratory causes.

The new study is the first to link ozone levels to the development of depression symptoms in adolescents over time. The symptoms may include persistent feelings of sadness or hopelessness, difficulty with concentration, sleep disturbances and suicidal thoughts.

“I think our findings really speak to the importance of considering air pollution’s impact on mental health in addition to physical health,” says lead researcher Dr. Erika Manczak, an assistant professor of psychology at the university, in a statement.

‘Even low levels of ozone exposure have potentially harmful effects’

The researchers analyzed data from a previous study about early life stress with 213 participants, ages 9 to 13-years-old, in the San Francisco Bay area. The team compared data about the youngsters’ mental health over a four-year period with Census tracts for their home addresses and air quality data for those tracts from the California Environmental Protection Agency. Kids who lived in areas with relatively higher ozone levels showed “significant” increases in depressive symptoms over time, even though the ozone levels in their neighborhoods didn’t exceed state or national air quality standards.

Manczak points out that their findings weren’t affected by the participants’ sex, age, race, household income, parental education or socio-economic characteristics of their neighborhoods.

“It was surprising that the average level of ozone was fairly low even in the communities with relatively higher ozone exposure,” she says. “This really underscores the fact that even low levels of ozone exposure have potentially harmful effects.”

Air pollution can trigger inflammation in children

Scientists say that ozone and other components of air pollution can contribute to high levels of inflammation in the body. Inflammation can lead to the onset and development of depression. Youngsters may be especially sensitive to these effects because they spend more time outdoors. The findings are correlational, the authors explain, so it can’t be proven that ozone levels caused an increase in depressive symptoms, only that there is a link between them.

It’s also possible that other components of air pollution besides ozone could be a factor.

Manczak believes communities should consider ways to reduce ozone exposure, such as holding youth sporting events indoors when necessary and limiting driving during peak hours of air pollution alerts. Lawmakers should put greater investment in clean and renewable energy sources that reduce air pollution could also be helpful.

“I believe air quality standards should be stricter, and we should have tighter regulations on industries that contribute to pollution,” she adds. “Our findings and other studies suggest that even low levels of ozone exposure can pose potentially serious risks to both physical and mental health.”

The study is published in the journal Developmental Psychology.

South West News Service writer Stephen Beech contributed to this report.