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A large body of scientific research has confirmed air pollution as a risk factor for a number of health issues, from respiratory infections to heart disease and skin conditions. The culprit is what’s known as particulate matter pollution, the term used to describe a mix of solid and liquid particles found in the air. 

All of these particles enter the body and impact our physical health. But what about our mental health? 

The brain and its functions are also affected by human-made air pollution. New research, including a significant study spanning more than a decade with more than 400,000 participants from a database in the United Kingdom, has found a link between long-term exposure to environmental contaminants and a higher risk of depression and anxiety. 

Researchers have observed that both visible particles of matter, such as dust, soot, or smoke, and those that can only be seen with an electron microscope can get past the body’s filtration systems, penetrating not just the lungs and other organs but also the brain, the center of mental illness. 

A recent review analyzing scientific literature on health and pollution revealed that air pollution was associated with physical and functional changes on the areas of the brain that regulate emotions across 95% of studies.  

Preclinical and human neuroimaging studies also indicate that exposure to air pollution could increase the risk internalizing psychopathology by altering brain regions such as the hippocampus, which regulates memory and emotions; the amygdala, which is responsible for monitoring our surroundings for important stimuli; and the prefrontal cortex, whose main functions include decision-making and impulse control.  

These regions of the brain play a key role in our response to stress and our ability to regulate emotions and are also involved in the physiopathology of so-called internalizing disorders, such as anxiety and depression. 

Ultrafine environmental particles, those that cannot be seen by the human eye, are especially known to impact the brain. They can do so directly, by traveling from the nose to the brain, or indirectly, by causing inflammation and altering immune system responses that can affect the brain. 

Air pollution-induced neurotoxicity could also play a role in neurodegenerative diseases such as Alzheimer’s and Parkinson’s. According to recent research, chronic exposure to pollution can cause inflammation in the brain and cell death, contributing to the development and progression of these illnesses. 

Mental Health in Big Cities

The environmental elements discussed above, which are beginning to be confirmed as risk factors for mental health, form part of layers of pollution that literally “float” above dozens of Latin American cities and render the air in these regions unhealthy. 

A study conducted in 366 cities in the region with more than 100,000 inhabitants found that 172 million people, or 58% of the studied population, lived in areas with pollution levels considered higher than normal by the World Health Organization. 

As is expected, mega-urban areas and industrial centers with larger populations and more cars generate more air pollution. Latin America has one of the biggest concentrations of urban areas in the world. According to data from the United Nations Economic Commission for Latin America and the Caribbean (ECLAC), in 2020, approximately 81% of the Latin American population lived in urban areas, equivalent to more than 540 million people. 

Neglected populations are especially impacted by air pollution, which tends to be worse in marginalized and more vulnerable areas with more traffic caused by trucks and private vehicles, higher gas emissions, and industrial waste. 

Air pollution is a complex challenge that requires a multifaceted approach, including: 

• Promoting research on the link between air pollution and mental health. More scientific data will help spark debate and generate change.  
• Understanding the sources of air pollution, a key first step to developing urban design techniques that reduce overall exposure. 
• Promote green spaces, which function as a city’s “lungs.” By helping cool urban areas and mitigating the so-called “urban heat island effect,” green spaces also help address air pollution by reducing photochemical ozone formation. The shade provided by urban trees also reduces energy demand, indirectly contributing to improved air quality. 
• Controling pollution through a greater international, regional, and local commitment to reducing vehicular and industrial gas emissions via a combination of policies, laws, and regulations. 

Reducing exposure to multiple air pollutants could also alleviate the disease burden of depression and anxiety. 

Remember, always consult with your physician or health care professional to determine the best options for your body and health and to answer any questions you may have regarding any medical matter.