Air pollution and depression
Air pollution and depression
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Can air pollution affect mental health?

Air pollution has been linked to numerous health problems. Scientific evidence shows that air pollution may affect mental health, too. Learn more.

A growing body of research suggests that air pollution can inflict some of the earliest and most long-lasting damage on our cognitive and mental health

This adds a new layer of complexity into an area of research that’s relevant to over 300 million people worldwide who experience a mental health condition like depression – a number that’s grown in the last decade by at least 18% (or 54 million more people).1,2 

The sheer amount of research supporting this notion is overwhelming – and we’re here to help you sort through it.

Here’s what’s on the horizon when it comes to establishing a link between air pollution and mental health, including:

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

How does air pollution affect mental health?

Let’s get right into it – research is starting to make a pretty good case that air pollution has a direct effect on your mental health. 

Some studies show that even brief, temporary air pollution exposure may cause debilitating mental health conditions like depression and schizophrenia. And the damage can start as early as childhood.

Air pollution and children’s mental health

Children’s brains and behavior are still developing up to their late teens and early adulthood, and air pollution may have an enormous impact on their mental and emotional growth.

One of the more ominous recent findings is the proposed link between PM2.5 and cases of mental health disturbances in young children that are serious enough to send them to the emergency room for psychiatric evaluation.

A 2019 study published in Environmental Health Perspectives studied short-term exposure to PM2.5 in over 6,800 children up to 18 years old who were sent to an emergency department at the Cincinnati Children’s Hospital Medical Center in Cincinnati, Ohio for symptoms considered psychiatric emergencies. These symptoms included suicidal thoughts and adjustment disorder (intense stress, sadness, and anxiety triggered by a major life event).3,4,5

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

The researchers suggest that PM2.5 exposure worsens existing inflammation in the brain caused by everyday stressors that result in mental health symptoms – specifically, in brain cells called microglia that react to life changes, social isolation, and bullying by becoming inflamed.6 

This means that children who are already stressed from the struggles of growing up could have a much higher chance of experiencing severe, sometimes emergency symptoms of mental health disorders when air pollution levels rise even a little bit.

These findings build on an earlier study that looked at how two dangerous pollutants common in city and traffic pollution, PM2.5 and nitrogen dioxide (NO2), could be connected to mental health issues like anxiety, depression, attention-deficit hyperactivity disorder (ADHD), and a group of behavioral disorders known as conduct disorders (some of which can turn into cases of sociopathic behavior in adulthood).7

This 2019 study, published in Psychiatry Research, 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, the researchers concluded 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.

You may be thinking that just as symptoms of mental health conditions get worse when airborne pollutants rise, they should also go away once air pollution levels fall.

But even long after exposure to increased levels of airborne pollutants, the impact of depression and conduct disorder on the developing brain has lifelong consequences.

In fact, childhood symptoms of mental health conditions like depression and anxiety could lay the groundwork in your brain’s wiring and chemistry for worsening mental health symptoms into the teen years and beyond.8 

Researchers involved in a groundbreaking 4-year longitudinal study published in JAMA Psychiatry in 2020 found that untreated mental health symptoms could permanently alter the brain’s activity by weakening connections between different parts of the brain that result in these symptoms. 

This means that the longer symptoms go unaddressed, the weaker the brain’s ability to process and cope with these symptoms may become, leading to permanent or chronic anxiety and depression. 

This supports 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 lives. This has enormous implications – chronic depression can sometimes be difficult to treat and impossible to cure, and its symptoms can become debilitating if left untreated.9

And children with conduct disorder, which can cause disruptive behavioral changes in children like aggression and a lack of empathy for others, often develop the symptoms of antisocial personality disorder in adulthood – better known as sociopathy.10

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 published 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 – about the same level of PM2.5 as someone who lives in a relatively pollutant-free suburb and commutes into a polluted city.11

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 even lost interest in simple pleasures they used to seem excited about, such as getting a sip of sugar water.

Intrigued by their findings, the researchers looked closely at the differences in the brains of these depressed mice and those not exposed to any pollution. 

The mice who’d been exposed to commuter levels of pollution had significantly more cytokines in their brains – one of the most notable signs of harmful inflammation in the body and one of the biggest contributors to mental health conditions like depression and anxiety.12   

These early findings have also been researched in humans – and the results are much more harrowing than those found in mice.

In an analysis published in PLOS Biology of 151 million people in the United States and 1.4 million people in Denmark, researchers found similar results to studies done on animals.13

In this analysis, researchers focused on four specific psychiatric conditions:

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

Even at such a large scale, the data showed that long periods of 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. 

The researchers pointed out that fine particulate matter like PM2.5 and ultrafine particles were the most notable suspects in the relationship between air pollution and mental health. 

Analyzing a series of earlier studies, the researchers laid out the following conclusions about what may happen in your brain when you breathe in airborne pollutants that may affect your mental health:

  1. Pollutants get into the lungs and cause inflammation in your windpipe and lungs. This can also inflame your nervous system. 
  2. Nervous system inflammation increases the number of inflammatory cytokines in your body and activates microglia that react to stress. This kind of body-wide inflammation can cause damage to your DNA.
  3. Pollutants also get into your brain through thin nose membranes, where neurons can transport PM2.5 through your olfactory (smell) system into brain tissue.
  4. Pollutants that get into the brain damage the brain itself as well as brain structures in the limbic system – which is directly responsible for your emotions. 
  5. Over time, repeated exposure to PM2.5 can cause more and more damage to your limbic system, potentially making mental health symptoms more severe.

How to protect yourself from air pollution and mental health conditions

Preserving good mental health is a lifelong challenge. This is especially true if you’re dealing with the emotional stress of work or life events along with the physical stress responses caused by air pollution and other environmental factors, such as polluted water or chemicals in plastics.

So here are some tips for keeping air pollution from exacerbating your symptoms and learn to manage your mental health.

1. Seek mental health treatment

This part is entirely up to you – and in some cases, your healthcare provider.

If your healthcare provider agrees, when you need to de-stress, try some of the following relaxing or stress-reducing activities to lessen your overall anxiety or stress:

  • listen to your favorite music
  • try deep breathing exercises
  • listen to or watch something funny, like stand-up comedy
  • drink less caffeine (if you’re a coffee or tea drinker)
  • exercise for about 15 minutes a day
  • do yoga
  • meditate a few minutes a day
  • use essential oils like lavender
  • keep a journal to write down your thoughts

Not all mental health conditions are treatable with behavioral or environmental changes – conditions like major depressive disorder, bipolar disorder, or schizophrenia result from factors out of your control, such as brain chemical imbalances or conditions like hypothyroidism. 

Stress reduction can help lessen your symptoms, but you’ll need to work with your doctor and a mental health specialist to make a treatment plan to manage your symptoms. This may include:

  • medications to balance chemical processes in the brain that affect mood
  • regular therapy to help you learn to cope with triggers of stress and depression
  • adjusting your diet to get enough of the nutrients that affect your mood, such as B vitamins and magnesium

2. Monitor your indoor and local air quality 

Knowing when concentrations pollutants spike can help you learn when to stay indoors to avoid outdoor pollution or to learn what areas of your home may contain high levels of pollutants, such as your garage or any areas where you or family members smoke. 

A smart air quality monitor can help you track your current air quality as well as see trends and forecasts in your local air quality so that you can plan ahead.

3. Keep the air you’re breathing clean

No matter where you live, it’s likely that you’ll encounter poor air quality at some point in your day:

  • At home – you’ll likely spend more than half your day at home.14 And your home can be the source of many dangerous airborne pollutants, such as particles and gas pollutants from appliances like stoves, chemical off-gassing from furniture and building materials, or pet dander from cats, dogs, and birds. Use a room air purifier or whole-house air purifier to make sure you’re breathing clean air in most or all of your home, especially in the bedroom, living room, or kitchen. 
  • In your car during your commute – according to the U.S. Census Bureau, the average commute is 26.1 minutes per day.15 Multiply that by two times a day, five days a week, 52 weeks a year, and that’s 13,572 minutes or more filled with particulate and dangerous oxides seeping into your car from vehicle exhaust and from interior vehicle components. Try a car air purifier during your commute to reduce your exposure to abnormally high concentrations of vehicle pollutants during traffic rush hours.
  • In your office 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, where bacteria and viruses are constantly transmitted among coworkers and chemicals originate from cologne and perfume as well as industrial cleaning products.16Keep a personal air purifier at your desk or in your office to breathe clean air whenever you’re sitting at your desk.

You’re not alone 

Breathing clean air might be a significant step you can take to reduce some environmental triggers. And clean air has a host of other positive effects, including improved cognitive function and greater longevity.17,18

Remember that mental health is holistic – there’s no cure-all for everyone’s mental health symptoms. Talk to your doctor or mental health provider to help you decide how to manage your symptoms in the long term. And call the National Suicide Prevention Lifeline anytime at 1-800-273-8255 if you or someone you know is struggling with suicide or suicidal thoughts.
 

Article Resources

[1] Other dimensions of the NCD crisis: from mental health, ageing, dementia and malnutrition to deaths on the roads, violence and disability. (2017). https://www.who.int/publications/10-year-review/ncd-other-dimensions/en/ 

[2] Ali NA, et al. (2019). Growing evidence for the impact of air pollution on depression. DOI: 10.31486/toj.19.0011

[3] Brokamp C, et al (2019). Pediatric psychiatric emergency department utilization and fine particulate matter: A case-crossover study. DOI: 10.1289/EHP4815 

[4] Mayo Clinic Staff. (2018). Suicide and suicidal thoughts. https://www.mayoclinic.org/diseases-conditions/suicide/symptoms-causes/syc-20378048

[5] Mayo Clinic Staff. (2017). Adjustment disorders. https://www.mayoclinic.org/diseases-conditions/adjustment-disorders/symptoms-causes/syc-20355224 

[6] Calcia MA, et al. (2016). Stress and neuroinflammation: A systematic review of the effects of stress on microglia and the implications for mental illness. DOI: 10.1007/s00213-016-4218-9

[7] Roberts S, et al. (2019). Exploration of NO2 and PM2.5 air pollution and mental health problems using high-resolution data in London-based children from a UK longitudinal cohort study. DOI: 10.1016/j.psychres.2018.12.050

[8] Whitfield-Gabrieli S, et al. (2019). Association of intrinsic brain architecture with changes in attentional and mood symptoms during development. DOI: 10.1001/jamapsychiatry.2019.4208

[9] Depression. (2018). https://www.nimh.nih.gov/health/topics/depression/index.shtml 

[10] Pisano S, et al. (2017). Conduct disorders and psychopathy in children and adolescents: Aetiology, clinical presentation and treatment strategies of callous-unemotional traits. DOI: 10.1186/s13052-017-0404-6

[11] Fonken LK, et al. (2011). Air pollution impairs cognition, provokes depressive-like behaviors and alters hippocampal cytokine expression and morphology. DOI: 10.1038/mp.2011.76

[12] Teeling JL, et al. (2009). Systemic infection and inflammation in acute CNS injury and chronic neurodegeneration: Underlying mechanisms. DOI: 10.1016/j.neuroscience.2008.07.031

[13] Khan A, et al. (2019). Environmental pollution is associated with increased risk of psychiatric disorders in the US and Denmark. DOI: 10.1371/journal.pbio.3000353

[14] Ingraham C. (2014, June 27). Here’s how you spend your days, America – in 10 charts. https://www.washingtonpost.com/news/wonk/wp/2014/06/27/heres-how-you-spend-your-days-america-in-10-charts/ 

[15] Average one-way commuting time by metropolitan areas. (2017). https://www.census.gov/library/visualizations/interactive/travel-time.html 

[16] American Time Use Survey summary. (2019). https://www.bls.gov/news.release/atus.nr0.htm 

[17] Schmidt S. (2019). Brain fog: Does air pollution make us less productive? DOI: 10.1289/EHP4869

[18] Chen Y, et al. (2013). Evidence on the impact of sustained exposure to air pollution on life expectancy from China’s Huai River policy. DOI: 10.1073/pnas.1300018110 

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