It’s no secret that air pollution is bad for you. But do you know it can harm your mental well-being and brain function?
Asthma, cancer, and heart disease are better-known health risks of air pollution. But growing evidence suggests toxic air may be a hidden factor in the rising rates of neurological disorders. (1, 2, 3)
In fact, studies now link air pollution to several nervous system ailments. These include depression, schizophrenia, Parkinson’s disease, bipolar disorder, epilepsy, and personality disorders. (4)
Genetic and biochemical factors can also contribute to these illnesses. But the role of environmental pollution shouldn’t be overlooked. After all, the air contains a toxic brew of chemicals and heavy metals.
Read on to learn how air pollution, heavy metals, and neurological disorders are connected. You’ll also find some practical ways to help protect your brain from pollution risks today.
What Is Air Pollution?
Polluted air contains toxic chemicals and compounds that can harm your health. Much of this pollution comes from factories, power plants, car exhaust, and wildfires. (4)
The toxins in the air can be gases, solids, or liquids. For example, carbon monoxide and sulfur dioxide are gases that pollute the air. And solid pollutants combine with liquid droplets to form particulate matter or tiny particles in the air. (5)
Have you ever wondered what makes the sky hazy sometimes? That’s from particulate matter.
Particulate matter is a mix of chemicals, black carbon (such as from burning fuel), dust, and heavy metals. Some heavy metals found in particulate matter are lead, cadmium, aluminum, and mercury. (6, 7, 8)
As you breathe, particulate matter enters your lungs. The smaller the particles, the more harmful they may be. Smaller particles can pass through your tissues more easily. That includes your brain. (6)
The pollution of the air with particulate matter is very concerning. Most of the world’s population lives in areas where particulate matter exceeds World Health Organization guidelines. And growing evidence suggests poor air quality may harm the mental health of billions of people. (10)
How Pollution Could Affect Your Brain
Air pollution is inflammatory and can damage your cells and DNA. That includes your nerves and brain tissues. This may play a role in brain dysfunction, including mental health disorders. (4)
Some research shows that the more particulate matter in a region’s air, the higher the risk of mental health disorders. But how do pollutants interact with your brain? Doesn’t the blood-brain barrier keep toxins out? Not if it’s damaged. (10)
Air pollution and heavy metals can weaken the blood-brain barrier. Animal research has shown that particulate matter can enter the brain. And, scientists have confirmed the presence of heavy metals from air pollution in human brains after death. (4, 11, 12)
In addition, animal and lab studies suggest air pollution could damage your brain by a few different routes: (4, 13, 14)
Systemic inflammation: As pollutants enter your lungs, they could trigger inflammation. This inflammation could spread to nerves distant from your lungs. That could trigger your brain cells to produce inflammatory molecules and damage DNA.
Immune cells: White blood cells called macrophages could engulf pollutants and carry them to your brain. This would stimulate your brain cells to produce damaging inflammatory molecules.
Nose: Toxins in the air may damage the barrier between your nasal passages and your brain. This gives pollutants easy access to your brain, including the limbic system. The limbic system is involved in emotions, learning, and memory.
Animal research suggests the hippocampus of the brain may be especially vulnerable to inflammatory damage from particulate matter. The hippocampus is part of the limbic system. (15)
Also, particulate matter may affect your risk of neurological problems by influencing gene expression. It could potentially “turn on” genes associated with mental health disorders. (16)
Keep reading to learn more about specific brain disorders and how air pollution could be a factor.
Pollution and Depression
About 7% of American adults have significant depression. It may affect about twice as many women as men. (4)
As you likely know, depression impacts your mood. It could manifest as sadness, emptiness, or a general lack of interest in life. Traumatic life events, financial issues, and chronic illness are among the potential triggers of depression. (17)
But what if there is a connection between air pollution and depression? Scientists think this might be the case.
In one large study, teens and young adults exposed to the highest rates of air pollution as children had about 50% higher rates of depression. This was compared to those who grew up in the cleanest air. (4)
Another study compared daily air pollution levels with the number of depression-related visits to the emergency room (ER). On days when particulate matter was elevated, 7% more women visited the ER. The same effect wasn’t observed for men. (18)
And, a study of older adults found a 17% rise in depression symptoms when particulate air pollutants were elevated. Plus, higher levels of certain gaseous pollutants were linked to a 33–44% increase in depression symptoms. (19)
Of course, these studies are observational and can’t prove air pollution is causing these effects. But animal experiments support this link between depression and air pollution.
When pregnant rodents were exposed to high levels of particulate matter, their offspring had altered brain development. The babies also had increased signs of depression compared to animals that weren’t exposed to the pollutants. (20, 21)
Pollution and Schizophrenia
Schizophrenia is a relatively uncommon but serious mental health disorder. It can change how you think, feel, and behave. You may have hallucinations, difficulty managing emotions, and trouble thinking clearly. (22, 23)
Several factors may contribute to the disorder. Irregular levels of chemical messengers in your brain are thought to play a role. Genetic factors, complications during birth, and virus exposure may increase your risk. (22, 23)
Scientists have also linked living in an urban setting with an increased risk of schizophrenia. This might be due to any number of factors related to city life, including air pollution. (24, 25)
Recently, a large study found that people exposed to the most air pollution in childhood had a 148% higher rate of schizophrenia than those growing up in the lowest pollution areas. (4)
Men may be at a slightly higher risk of schizophrenia than women. Some evidence suggests one reason for this is because more men work outdoors. That would expose them to more air pollution. (23, 26)
Researchers think that particulate matter is one factor in air pollution that may increase schizophrenia risk. Animal research supports this idea. (27)
When newborn mice were exposed to particulate matter, it caused structural brain changes commonly found in schizophrenia. These changes were found in male but not female mice. That’s consistent with human studies that show a little higher risk of schizophrenia in men. (23, 28)
Pollution and Parkinson’s Disease
Parkinson’s disease affects around 0.2% of the U.S. population, which is about 660,000 Americans. Men are almost twice as likely as women to develop the condition. (4, 29)
In this disease, nerve cells in a part of your brain that controls movement are damaged or die. That can result in tremors, poor balance, and trouble walking, among other symptoms. (29)
But before these severe impairments, more subtle alterations are going on behind the scenes. Figuring out the causes of early changes may point to preventable causes of the disease. (30)
A common change leading up to Parkinson’s is damage to the olfactory bulb, located above your nasal cavity. This structure helps process smell signals. Damage to it can weaken your sense of smell. (31)
Some evidence suggests injury to the olfactory bulb may be due to inhaling pollutants. This includes tiny airborne heavy metals, such as found in particulate matter. These metals may pass into your brain, leading to inflammation and nerve damage. (32, 33)
This brain inflammation may increase a protein called alpha-synuclein. It helps nerve cells receive messages. But in excess, these proteins can clump. That can disrupt the mitochondria in nerve cells — including in brain regions that control movement — and trigger nerve cells to die. (30, 34)
Consider a study done in Mexico City, one of the most highly polluted cities in the world. The research found healthy children already had alpha-synuclein buildup in their brain. This supports a link between air pollution and brain abnormalities that lead to Parkinson’s disease. (32, 35)
Pollution and Bipolar Disorder
Bipolar disorder — sometimes called manic-depressive disorder — affects about 3% of U.S. adults. It can cause extreme changes in your mood and energy levels. You can feel very “high” and energetic, and then suddenly very “low” and sad. (36)
Experts aren’t sure what causes bipolar disorder. Genetics likely play a role, and the disease tends to run in families. (37)
In addition, several studies have linked bipolar disorder to parasitic infection with Toxoplasma gondii. That’s a single-celled parasite you can get from undercooked, contaminated pork. You can also get it from contact with cat feces tainted with the parasite. (37, 38, 39)
Interestingly, studies have also linked allergies and asthma to increased risk of bipolar disorder. In turn, asthma is commonly associated with air pollution. So, could bipolar disorder have something to do with air pollution? (2, 37)
Recently, a large study found that areas of the United States with the worst air quality had a 29% higher rate of bipolar disorder than regions with the cleanest air. (4)
Though more research is needed, such a link is plausible. Air pollution is associated with increased nerve inflammation and overstimulation of brain cells. And brain tissue from people with bipolar disorder has shown increased nerve inflammation and overstimulated nerves. (40)
Pollution and Epilepsy
Epilepsy is a seizure disorder that affects about 1.2% of Americans. It results from overactivity of your brain, meaning it sends too many nerve signals. Symptoms may range from small muscle twitches to full-body convulsions. (41, 42)
The cause of seizures isn’t always clear. Sometimes they’re triggered by injuries, strokes, or tumors. In addition, brain inflammation is a risk factor for seizures. (42)
Could air pollution be one cause of the brain inflammation that leads to seizure activity?
Studies in China — which has the highest air pollution in the world — have linked air pollution with epilepsy. Doctor visits and hospitalizations for epilepsy increase on days of higher air pollution in China. This pollution includes particulate matter, which contains heavy metals. (43, 44)
Other research links heavy metals like lead, nickel, and mercury in the environment with higher epilepsy risk. Children may be especially vulnerable to the effects of heavy metals and air pollution. (45, 46)
Pollution and Personality Disorders
Personality disorders involve extreme thought patterns. Some examples are antisocial behavior, obsessive-compulsive disorder, and narcissism. They can stand in the way of living a normal life and having healthy relationships. (47)
Unlike some mental health disorders, personality disorders are relatively common. It is estimated that 4–15% of people in the United States and Europe have personality disorders. (47)
Both genetic and environmental factors contribute to the risk of personality disorders. This may include toxicity from air pollution. (48)
A recent, large study of teens and young adults is worrisome. It found that those exposed to the highest air pollution through age 10 had a 162% higher rate of personality disorders compared to those who grew up in the cleanest air. (4)
More research is needed. But this preliminary study suggests dirty air may contribute to unhealthy personality shifts.
How to Protect Your Brain
You can’t entirely avoid air pollution in today’s world. But that doesn't mean you’re helpless to protect yourself and your family from air pollution and heavy metal toxicity.
Several supplements, diet, and lifestyle choices could help support and protect your brain.
Dietary supplements that help with detox could be an important part of your arsenal against air pollution. The sooner you’re able to get rid of heavy metals and other toxins from air pollution, the less they can impact your brain.
Carbon-based binders can form potent binders of heavy metals and other pollutants. These plant-based extracts of humic and fulvic acids have the ability to “take out the garbage” in your brain. They’re strong enough to carry heavy metals all the way out of your body, as explained in this short video. (49)
But carbon-based binders do more than haul away toxins. They contain amino acids, minerals, and antioxidants. In short, they have everything your cells need to repair and rebuild after toxin exposure.
Another helpful detox supplement is TUDCA. It may help increase your body’s natural excretion of bile. That’s one drainage route by which your body purges heavy metals and other toxins your liver processes from your blood.
TUDCA may also protect your brain and nerve cells. One animal study suggests TUDCA may reduce stress-induced epileptic seizures. This may be due to its ability to reduce damage from oxidative stress in nerve cells. (50, 51)
Lastly, heavy metals may create a low oxygen environment called hypoxia. Your brain needs a lot of oxygen to work well. Taking a stabilized molecular oxygen supplement may help protect your brain from air pollution. (12, 52)
You can’t control what’s lurking in outdoor air, but you can certainly control your diet. Your food choices may help counteract the effects of pollution. Eating healthy foods is also vital for good brain health and mental health in general. (53, 54)
Vitamins A (beta-carotene), C, and E are antioxidants. They may help squelch the oxidative stress in your body, such as from air pollution. Here are some sources of each: (55, 56, 57)
Vitamin A: orange and yellow fruits and vegetables
Vitamin C: bell peppers, kale, broccoli, oranges, strawberries
Vitamin E: almonds, sunflower seeds, hazelnuts, avocados
Plant-based foods also provide phytochemicals. These have antioxidant and anti-inflammatory properties. And they may help blunt the toxic effects of air pollution. (58)
In addition, a vitamin-like nutrient called choline supports brain health. You need it to make certain nerve messengers. Choline deficiency is linked to brain disorders and inflammation. The nutrient is found in meat, eggs, poultry, and quinoa. (55, 59)
Healthy fats are also important for brain function. An animal study suggests omega-3 fats may help prevent inflammation from particulate matter. You can get omega-3 fats from chia seeds, flaxseeds, and low-mercury fish like sardines and wild-caught salmon. (11, 55)
On the flip side, an excess of omega-6 fats can increase inflammation. Those are abundant in soybean and corn oils, which are prevalent in the Western diet. Read labels and avoid those oils as much as possible. (60, 61)
Change starts with you. Consider what you can do to help reduce air pollution. Your efforts could have a ripple effect that impacts future generations.
For example, can you carpool or take public transportation? “Go green” in other ways as well. If you can, plant trees. And encourage your city to develop more green spaces, such as parks and community gardens.
One study found that children who grew up with the least amount of green space had a 55% higher chance of mental health disorders. Green spaces help soothe stress as well as decrease air pollution. Trees, bushes, and other foliage help cleanse the air of toxins. (62, 63)
Still, you should limit your time outside if poor air quality advisories have been issued. For example, in the United States, you can check the daily Air Quality Index. (64)
Lastly, don’t forget the pollutants in your home. Whole-house air filtration systems are sold as part of some heating, ventilation, and air conditioning (HVAC) units. You can also buy portable air purifiers to remove chemical pollutants. While you’re at it, choose a purifier that also removes mold toxins. (65)
Defend Your Brain
Like pesticides, polluted air is a toxic chemical cocktail. It contains harmful gases as well as particulate matter composed of heavy metals and other toxins.
Growing evidence suggests the toxins in air pollution increase your risk of poor mental health and brain disorders. That includes depression, Parkinson’s disease, and several others.
Thankfully, there are several ways you can protect yourself against these contaminants that could harm your brain.
You can take carbon-based binders and TUDCA supplements to promote the removal of pollutants from your body. You can also follow a nutritious diet and limit time outdoors on days of poor air quality.
What changes will you make today to protect your brain from air pollution?