An estimated 280 million people worldwide experience a mental health condition like depression (1). Research suggests that exposure toair pollution may inflict some of the earliest and most long-lasting damage on cognitionand mental health (2).

Some major areas of research linking air pollution and mental health include:

• which pollutants may be most detrimental to mental health, from direct exposure as well as both short- and long-term exposure
• how air pollution may impact children and adults differently, especially in relation to mental and emotional development
• how to help protect yourself, your children, and those around youfrom the effects of air pollution on your mental health

How does air pollution affect mental health?

Research increasingly illustrates the impact that dirty air has on mental illness.

Some studies show that even brief, temporary air pollution exposure may be linked to an increased risk for mental disorders like depression and schizophrenia, with damage starting as early as childhood.

Air pollution and children’s mental health

The World Health Organization estimates that over 90 percent of children around the world breathe polluted air at levels considered detrimental to health and development (3).

Since children’s brains and behavior are still developing up to their late teens and early adulthood, air pollution—especially PM2.5(particulate matter with a diameter size of 2.5 microns or smaller)—may have an outsized impact on their mental and emotional development, with effects on cognitive and behavioral outcomes as well.

PM2.5 is particulate matter pollution measuring 2.5 micrograms per cubic meter (μg/m3) or less. Among air pollutants that are typically measured, it is widely recognized that PM2.5 has the greatest impact on health.

One proposed link between PM2.5 and cases of mental health disturbances in young children suggests that extreme cases of mental health symptoms resulting from air pollution exposure are serious enough to send children to the emergency room for psychiatric evaluation.

A 2019 study in Environmental Health Perspectives studied short-term exposure to PM2.5 in over 6,800 children up to 18 years old sent to an emergency department at the Cincinnati Children’s Hospital Medical Center in Cincinnati, Ohio for symptoms considered psychiatric emergencies, including (4)(5)(6):

1. suicidal thoughts or behavior
2. adjustment disorder (intense stress, sadness, and anxiety triggered by a major life event)

The study concluded that even a small, short-term increase in PM2.5 of 10 micrograms per cubic meter may be responsible for a significant increase in the number of children brought to the hospital for severe psychiatric symptoms.

The researchers also suggested that PM2.5 exposure worsens existing inflammation in the brain caused by everyday stressors that result in mental health symptoms.

A 2016 review article in Psychopharmacology specifically looked at the role of brain cells called microglia due to their documented inflammation in response to life changes, social isolation, and bullying (7). In examining the mental health literature, the researchers concluded that increased microglial inflammation from stress may increase a child’s risk of mental health disorders later in life.

In connection with the stress brought on by air pollution exposure, this means that children already stressed from the struggles of growing up as well as stressors linked to, for example, family instability, abuse, or poverty may have an even higher risk of severe, sometimes emergency mental health symptoms when air pollution levels rise even a little bit.

A 2020 study in Toronto, Canada validated this link between air pollution and emergency room (ER) visits for mental health symptoms (8).

Looking at 83,985 ER visits for people aged 8-24 from April 2004 and December 2015, researchers found that increases in PM2.5, ozone, and nitrogen dioxide were all associated with increased ER visits, sometimes up to 5 days after initial exposure to that pollutant.

Researchers calculated just how much each pollutant needed to rise in airborne concentration to result in increased ER visits for mental health emergencies:

• PM2.5: 6.03 μg/m3
• Nitrogen dioxide: 9.1 parts per billion (ppb)
• Ozone: 16 ppb
  

These two studies build on an earlier 2019 study in Psychiatry Research that looked at whether PM2.5 and nitrogen dioxide (NO2) were connected to mental health issues like anxiety, depression, attention-deficit hyperactivity disorder (ADHD), and conduct disorders (9).

This study focused on 284 children who were part of a long-term study of twins born to nearly 1,200 families in the United Kingdom between 1994 and 1995.

Using air quality data from the addresses of these twins’ families along with mental health data from medical and psychiatric evaluations of the children themselves over time, researchers found that even relatively low PM2.5 and NO2 exposure in childhood may increase the risk of major depressive disorders and conduct disorders by age 18. The higher the pollutant concentration, the higher the possible risk of depression.

It’s tempting to think that, since symptoms of mental health conditions get worse when airborne pollutants rise, they should also diminish once air pollution levels fall.

But the impact of air pollution on mental health and cognitive development persists long after exposure to increased levels of airborne pollutants.

Childhood symptoms of mental health conditions like depression and anxiety may also lay the groundwork in the brain’s wiring and chemistry for increasingly severe mental health symptoms into the teen years and beyond.

A 4-year longitudinal study published in JAMA Psychiatry in 2020 found that mental health symptoms left untreated in childhood could permanently alter brain activity. This happens when connections between different parts of the brain are weakened by mental health conditions and can result in the development of conditions like anxiety, depression, and attention disorders (10).

The longer symptoms go unaddressed, the weaker the brain’s ability to process and cope with these symptoms. This can lead to permanent or chronic anxiety and depression that may continue to persist until treated with behavioral or psychiatric interventions.

This study lends significant support to the idea that air pollution exposure in childhood may cause mental health symptoms that could change the way a child’s brain processes emotions for the rest of their life.

This has enormous implications. Conditions like anxiety and depression can sometimes be difficult to manage, and symptoms can become debilitating if left untreated or without sustainable management strategies (11). Air pollution exposure can increase the severity of these symptoms or cause them to appear in children who may have had no previous risk factors for mental health conditions.

Children with conduct disorder, a condition associated with disruptive behavioral changes like aggression and a lack of, also tend to develop the symptoms of antisocial personality disorder in adulthood – better known as sociopathy (12).

^{Air pollution and mental health issues in adults}

The effects of air pollution on mental health aren’t just limited to children.

Many findings on air pollution and depression, specifically, first came out of research done on mice and how their behavior changed in response to air pollution exposure.

In a 2011 study in Molecular Psychiatry, researchers exposed mice to increased PM2.5 levels for eight hours a day, five times a week for a 10-month period. This is about the same level of PM2.5 exposure as someone who lives in a relatively pollutant-free suburb and commutes into a polluted urban area (13).

The researchers found not only that PM2.5 exposure may have made it harder for mice to learn new tasks, such as how to get through a new maze layout, but also that mice exposed to heightened PM2.5 showed classic signs of depression in mice. They gave up more quickly during difficult tasks and appeared to lose interest in activities that the mice were once excited about, such as getting a sip of sugar water.

Researchers then looked closer at the differences in the brains of depressed mice exposed to air pollution and those not exposed to any pollution who didn’t show similar signs of depression.

The mice who’d been exposed to commuter levels of pollution had significantly more cytokines in their brains. Cytokines are among the most notable signs of harmful inflammation in the body and one of the biggest contributors to mental health conditions like depression and anxiety(14).

These early findings have also been researched in humans – and the results appear more extreme than those found in mice.

In a 2019 analysis in PLOS Biology, researchers looked at mental health data from 151 million people in the United States and 1.4 million people in Denmark, focusing on four specific psychiatric disorders (15):

• bipolar disorder
• major depressive disorder
• personality disorder (like conduct disorder)
• schizophrenia

At this large scale, researchers found that long periods of exposure to increased air pollution, such as that found in major urban areas, may be linked to a nearly 17% rise in cases of bipolar disorder.

This also held true for major depressive disorder, with air pollution believed to have increased depression diagnoses by up to 6%, and personality disorder, with increases in diagnoses by almost 20% in some cases.

Researchers pointed out that particulate matter, including PM2.5 and ultrafine particles, were likely the most significant actors in the relationship between air pollution and mental health in their analysis.

Further analyzing a series of earlier studies, the researchers also posed the following links between airborne pollutants and mental health:

• Pollutants get into the lungs and cause inflammation in the windpipe and lungs. This can also inflame the nervous system.
• Nervous system inflammation increases inflammatory cytokines in the body and activates microglia that react to stress. This body-wide inflammation can damage DNA.
• Pollutants can get into the brain through thin nasal mucous membranes. Here, neurons can transport PM2.5 through your olfactory (smell) system into brain tissue, resulting in long-term brain damage.
• Pollutants that get into the brain can damage the brain itself as well as the limbic system, which consists of brain structures responsible for how the body processes and responds to emotions and memories.
• Over time, repeated exposure to PM2.5 can cause more and more damage to the limbic system, potentially worsening mental health symptoms or increasing their incidence.

How to protect yourself from air pollution and mental health conditions

Improving and maintaining mental health is a lifelong challenge. This is especially true in regards to the emotional stress of work or life events along with physical and mental responses to air pollution and other environmental factors, such as polluted water or chemicals in plastics.

Here are some tips to help keep air pollution from exacerbating mental health symptoms and better manage mental health.

1. Seek mental health treatment

Mental health treatment plans will vary from person to person based on symptoms and diagnoses. A holistic plan should be designed by a person and their healthcare or mental health provider to uniquely fit a person’s individual needs.

Not all mental health conditions are manageable solely with behavioral or environmental changes. Conditions like major depressive disorder, bipolar disorder, or schizophrenia can result from underlying causes like brain chemical imbalances or conditions like hypothyroidism. These conditions may require additional medication for desired psychological and behavioral outcomes.

Stress reduction can help reduce symptoms, but a treatment or management plan prescribed by a doctor or licensed mental health specialist may be necessary to help control lifestyle disruptions from mental health symptoms.

2. Monitor your indoor and local air quality

Knowing air pollution trends can help you learn when to stay indoors to avoid outdoor pollution or to learn what areas of your home or workplace may contain high levels of pollutants, such as your garage or any areas where people smoke.

An air quality monitor can help track current air quality as well as see trends and forecasts in your local air quality to plan ahead.

3. Improve indoor air quality

It’s possible to encounter poor air quality at any point in the day. Many people spend up to 90% or more of their day indoors, so using strategies to improve indoor air quality can help reduce mental health symptoms associated with air pollution.

At Home

Many people spend more than half of their day at home sleeping, eating, and doing household activities (16). And the home can be a source of many dangerous airborne pollutants, such as:

• particles and gas pollutants from appliances like stoves
• VOCs and chemical from furniture and building materials
• pet dander from cats, dogs, and birds

Use a room air purifier or whole-house air purifier to help keep the air clean in individual spaces or throughout an entire home, especially in bedrooms, living rooms, or kitchens where most people spend the majority of their time indoors at home.

During a commute

Across 19 major countries, daily average commute time ranges from 23 minutes (Italy) to 56 minutes (China) (17).Multiply that by the typical commute—five days a week, 52 weeks a year—and that’s an average of 5,980 to 14,560 minutes each year when an individual may be breathing in particulate matter and dangerous oxides that seep into cars from outdoor vehicle exhaust and interior vehicle components.

Try a car air purifier to help reduce exposure to abnormally high concentrations of vehicle pollutants during traffic rush hours.

In the office or at work

The Bureau of Labor Statistics reports that most full-time workers in the United States spend up to 8.5 hours a day at work. Bacteria and viruses are frequently transmitted among coworkers, and chemicals can originate from cologne and perfume as well as industrial cleaning products(18).

Keep a personal air purifier at workspaces, cubicles, or offices to breathe clean air whenever working at a desk or shared workspaces.

Building air quality improvement programs like IQAir Clean Air Facility can also identify major sources of poor indoor air quality at work and help mitigate air pollution through HVAC air filtration or other customized solutions.

You’re not alone

Breathing cleaner air is a significant step toward reducing some environmental triggers of mental health symptoms. Clean air also has a host of other positive effects, including improved cognitive function and greater longevity (19)(20).

Mental health treatment and management is holistic – there’s no single solution for everyone’s mental health symptoms. Talk to a physician or mental health provider to help decide how to manage symptoms in the long term.

Call the Suicide Prevention Hotline in your country or dial 988 in the United States anytime at if you or someone you know is struggling with depression and suicide or suicidal thoughts (21).