Ozone Exposure Linked to Adolescent Depression

Researchers from the University of Denver and Stanford University found evidence that ozone exposure in adolescence is linked to depressive symptoms, such as feeling sad or tearful, withdrawing socially, and losing interest or pleasure in activities.

Ozone, a common air pollutant, could be one of the causes of depressive symptoms in adolescents, according to a new study. The pollutant could have especially profound effects on mental health during the onset of puberty. This raises concerns about youth exposure to the chemical.

The researchers followed the mental health symptoms of 213 adolescents (ages nine to 13) who lived in communities with various levels of ozone exposure. They determined that those teens with higher levels of exposure were more likely to have increased depressive symptoms over a four-year period. Depressive symptoms among young people are more common, especially among girls.

The Pandemic

Policies pushed by governments in the wake of the Covid-19 pandemic have also increased rates of depressive symptoms among adolescents. Globally, the prevalence of symptoms of depression and anxiety in children and adolescents has doubled since pre-pandemic estimates.

Evidence has accumulated in recent years that air pollution, and ozone in particular, can cause adverse mental health effects, said lead author and University of Denver psychology professor Erika Manczak.  For example, hospitals in cities with high levels of ozone pollution prescribe more antidepressants than other hospitals.

Last year, Environmental Health News reported on the growing link between air pollution and mental health. The anxiety that comes with dealing with health problems related to air pollution was highlighted, as well as people’s increased risk of diagnoses like schizophrenia, bipolar disorder and major depression.

Living in poor air quality conditions

The new study, published by the American Psychological Association, provides the first data on individual mental health, rather than community trends.

Ozone is a chemical byproduct that is released when other air pollutants from combustion sources, such as automobile exhaust and manufacturing, are exposed to sunlight.

Three out of eight Americans live in counties with ozone levels rated “F” by the American Lung Association. This means that these places experience an unusually high number of days with unhealthy air. Western and southwestern cities have the highest levels of ozone pollution.

Researchers are still trying to determine how ozone, in particular, stimulates depressive symptoms. However, inflammation, a well-documented cause of adverse mental health symptoms, is a likely culprit. When people breathe in ozone, it can disrupt certain cellular processes and cause changes in the brain that cause inflammation.

Beyond mental health issues, ozone pollution has been linked to other human health issues. These include increased susceptibility to respiratory viruses, asthma, and premature death.

Environmental injustice

Because sources of air pollution are disproportionately located in low-income neighborhoods and communities of color, improving air pollution is an environmental justice issue.

According to Manczak, a community near a freeway might be at higher risk for ozone-related mental health problems than a community with less exposure to car exhaust.

These communities are often at risk for other stressors that can lead to mental health problems. Among them are poverty, noise pollution and difficulty in accessing goods and services. Ozone is yet another burden. “Air pollution is an additional contributor to mental health disparities,” Manczak said.

Sensitive period of development

The results also point to the possibility of a “sensitive period” of adolescent development. The researchers didn’t see such a strong correlation between ozone exposure and mental health until the onset of puberty.”Adolescence … could be a time of increased vulnerability,” Manczak said.

Small changes to avoid air pollution

Because ozone is invisible, it is difficult to encourage behavioral changes in response. However, ozone is not entirely unpredictable, ozone pollution is more prevalent during the summer months, or when there is little wind or air does not circulate normally.

In addition, there are important ways to control exposure. These include small changes, such as checking the air quality on a weather app before heading out, Manczak said.

“Getting people to pay attention to those things makes a big difference as the study potentially highlights that even fairly low exposures could increase risk, and do so in a faster time frame than we tend to think,” Manczak concluded.