The Link Between Pollution and Depression in Teens

In the United States, rates of teen depression are on the rise.

The pandemic increased awareness about the increase in teen mental health issues in general. Experts on adolescent development warned the accumulated stressors of stay-at-home orders, virtual school, and uncertainty/fear of disease and illness would exacerbate existing mental health issues among teens already diagnosed with a mental health disorder, and increase risk of mental health issues among teens not previously diagnosed with a mental health disorder.

When initial data on teen mental health and teen depression appeared in late 2020, the Surgeon General of the United States issued and advisory on teen mental health. To learn about that advisory, please read this article in the Parenting Tips and Advice section of our website:

Surgeon General’s Advisory: Youth Mental Health in 2021

The Surgeon General didn’t pull any punches: our teens are currently in the midst of a mental health crisis. It didn’t start with the pandemic. Let’s take a look at rates of depression among teens over the past ten years so we can understand the scope and reality of the problem.

Depression, Ages 12-17, United States, 2010-2020

• 2010
  • Major Depressive Episode (MDE): 8.0%
  • MDE with severe impairment (MDE/SI): 5.7%
• 2011:
  • MDE: 8.2%
  • MDE/SI: 5.7%
• 2012
  • MDE: 91%
  • MDE/SI: 6.3%
• 2013
  • MDE: 10.7%
  • MDE/SI: 7.7%
• 2014
  • MDE: 11.4%
  • MDE/SI: 8.2%
• 2015
  • MDE: 12.5%
  • MDE/SI: 8.8%
• 2016
  • MDE: 12.8%
  • MDE/SI: 9.0%
• 2017
  • MDE: 13.3%
  • MDE/SI: 9.4%
• 2018
  • MDE: 14.4%
  • MDE/SI: 10.0%
• 2019
  • MDE: 15.7%
  • MDE/SI: 11.1%
• 2020:
  • MDE: 17%
  • MDE/SI: 12%

Those numbers are sobering.

The rate of teens reporting a major depressive episode increase by 112 percent between 2010 and 2020, and the rate of teens reporting a major depressive episode with severe impairment increase by 110 percent.

In other words, they both doubled.

That’s why the Surgeon General described the state of teen mental health in the U.S. as in crisis, with increases in teen depression among the most alarming developments. While most parents of teens understand the basic risk factors for teen depression, a recent study identified another: air pollution.

We’ll examine that study in a moment.

First, we’ll look at the most commonly known and accepted risk factors for teen depression.

Teen Depression: Risk Factors

Decades of research identify the following risk Factors for teen depression:

• Family history of mental illness
• Disrupted family relationships
• Personal history of depression
• Substance use
• Significant events such as moving or changing schools
• Traumatic life events, such as a death in the family, major accidents, significant illness
• Significant trauma such as physical, sexual, and/or emotional abuse
• Adverse childhood experiences
• Extreme stress related to family, school, friends, or current events

Those are the most widely recognized and accepted risk factors for teen depression. These factors are associated with increased likelihood that a teen will develop clinical depression, and in some cases may be considered causes of clinical depression in teens.

We’re almost ready to discuss that new study that explores the link between air pollution and depression in teens. Before we get to that data, however, we’ll discuss what we know about the impact of air pollution on teen physical health and teen mental health.

Air Pollution and Teen Health: Physical Health and Mental Health

The Centers for Disease Control (CDC) indicate that ground level ozone, which is a key component of what people know as smog, is associated with a variety of physical health problems, including:

• Diminished lung function
• Increased hospital admissions and emergency room visits for asthma
• Premature death

As early as 1995, the CDC published warnings about ground level ozone pollution, which they describe in the following way:

“Ozone pollution results when hydrocarbons and nitrogen oxides emitted from motor vehicles and other sources react in the presence of sunlight.”

In addition to the health problems listed above, the CDC indicates ozone pollution contributes to exercise-related:

• Wheezing
• Coughing
• Chest-tightening

Respiratory issues are not the only health problems associated with ozone pollution. A study published in 2021 examined the effect of air pollution on brain function and mental health. Researchers explored the consequences of living in areas with high levels of air pollution on cognitive function, anxiety, depressive symptoms, and stress response.

Here’s what they found:

• Cognitive function
  • Result: high levels of air pollution were associated with decreased cognitive function
• Anxiety:
  • Result: high levels of air pollution were associated with increased anxiety
• Depressive symptoms
  • Result: high levels of air pollution were associated with increased depressive symptoms
• Stress response
  • Result: high levels of air pollution were associated with impaired stress response
    • In individuals with a genetic risk for depression, high levels of air pollution increased stress response impairment

As of last 2021, that was our understanding of the impact of air pollution on mental health: in areas of high pollution, exposure to ground ozone increased risk of mental health disorders. There’s a confounding fact about the study above, though. Researchers collected data in Beijing, China, a city known as having some of the poorest air quality on the entire planet.

The study that has our attention today examines the effect of pollution in an area where smog and ozone pollution is an issue, but nowhere close to the levels seen in Beijing: the San Francisco Bay Area of California.

Ozone Pollution and Teen Depression in San Francisco, California

The study “Census Tract Ambient Ozone Predicts Trajectories of Depressive Symptoms in Adolescents” examined the impact of local ozone levels on depressive symptoms in teens over a four-year period. This study is relevant because it builds on data published by several iterations of the Southern California Children’s Health Study that showed two things:

1. Air pollution increases health risk to kids and teens
2. Improving air quality and decreasing pollution decreases health risks to kids and teens

This study builds on that data by including mental health in the conversation about air pollution. As we show above, exposure to ozone – i.e. air pollution – is a well-documented risk factor for negative physical health consequences. This study asks the question:

What impact does air pollution have on teen depression in San Francisco?

Let’s take a look at how the researchers answered this important line of inquiry.

Participants included:

• 213 adolescents ages 9–13 years at baseline
  • 57% female/43% male
  • 53% of minority/47% non-minority

The study metrics – i.e. how they measured the data they collected – include the following:

• Self-report questionnaires on depression and mental health issues
• Participants surveyed three times
• Survey answers cross-referenced with census data for participant locations
• Census data cross-referenced with environmental data from the California Environmental Protection Agency (CalEPA) on neighborhood ozone levels

That’s how they did it: they collected information on teen depression over four years, determined where participants lived, identified the levels of air pollution in those areas, then compared levels of air pollution to levels of depressive symptoms.

Here’s what they found.

Adolescents in neighborhoods with higher ozone levels reported:

• Higher levels of depressive symptoms
• Increase in depressive symptoms during study period
• Increases appeared in neighborhoods where ozone levels did not exceed state or national air quality standards
• Sociodemographic factors – sex, age, race, household income, education – did not affect results

That data helps us understand something critical: ozone pollution can have a negative impact on mental health at levels state and national regulators do not consider dangerous. Specifically, higher relative levels of ozone can increase symptoms of depression in teens. Interviewed in the online magazine Science Daily, study author Dr. Erika Manczak offers this assessment of the data:

“I think our findings really speak to the importance of considering air pollution’s impact on mental health in addition to physical health…I believe state and federal air quality standards should be stricter, and we should have tighter regulations on industries that contribute to pollution. 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 data backs up her assertion: if pollution has a negative impact not only on physical health but also mental health, then the movement toward increasing air quality standards is essential as we move forward into the middle of the 21^st century and beyond.

Parents concerned their teen may have developed depression should understand that treatment for teen depression is safe and effective. We’ll end this article with a brief discussion on teen depression treatment.

Treatment for Depression in Teens: What Works?

Evidence shows the most effective treatment for depressive disorders follows the integrated treatment model. Integrated treatment is a comprehensive approach that involves a combination of psychotherapy, counseling, lifestyle changes, complementary supports, and medication, if needed.

Here are the most common, evidence-based treatment modalities for teen depression:

• Individual therapy for teen depression:
  • Cognitive behavioral therapy (CBT)
  • Mindfulness based cognitive behavioral therapy (MBCBT)
• Group therapy for teen depression:
  • Group CBT
• Family therapy for teen depression:
  • Multi-family groups
  • Parenting groups
• Mindfulness-based stress reduction:
  • Meditation
  • Yoga
• Complementary supports:
  • Experiential therapies:
    • General exercise
    • Outdoor activities
  • Expressive therapies, which may include:
    • Visual art
    • Writing
    • Music
    • Dance
    • Drama
  • Medication:
    • Antidepressants

We advise parents who think their teen may need treatment for depression to arrange a full biopsychosocial evaluation with a trained mental health professional. They can identify or rule out the presence of clinical depression, and if they arrive at a diagnosis of clinical depression, they can offer referrals for evidence-based treatment.

Treatment for teen depression works – and the sooner a teen who need treatment for depression gets the treatment they need, the better the outcome.

Finding Help: Resources

If you’re seeking treatment for your teen, please navigate to our page How to Find the Best Treatment Programs for Teens and download our helpful handbook, A Parent’s Guide to Mental Health Treatment for Teens.

In addition, the American Academy of Child and Adolescent Psychiatry (AACAP) is an excellent resource for locating licensed and qualified psychiatrists, therapists, and counselors in your area. Both the National Institute of Mental Health (NIMH) and the National Alliance on Mental Illness also provide and high-quality online resources, ready and waiting for you right now.