Air pollution is becoming a significant public health concern, affecting many aspects of health, including cognitive health. As urbanisation continues to rise globally, understanding the relationship between air pollution and cognitive function becomes crucial. This article examines air pollution’s impact on cognitive health, discusses emerging research findings, and explores the necessary public policy implications.

Understanding Air Pollution

Air pollution consists of harmful atmospheric substances primarily caused by human activities. Key pollutants include:

• Particulate Matter (PM): Tiny particles, such as PM2.5, can penetrate the respiratory system and are particularly harmful due to their small diameter of fewer than 2.5 micrometres.
• Nitrogen Dioxide (NO₂): Emitted from vehicles and industrial facilities, NO₂ can irritate the lungs and lower resistance to respiratory infections.
• Black Carbon: Black carbon is produced from incomplete combustion of fossil fuels and biomass.

Cognitive Health and Its Importance

Cognitive health means the ability to think, learn, and remember. It is essential for daily functioning and overall quality of life. Cognitive impairment can lead to significant social and economic burdens, including increased healthcare costs and reduced productivity.

According to Alzheimer’s Disease International, approximately 55 million people worldwide were living with dementia in 2020, and this number is expected to double every 20 years.

Dementia is a disorder in which a person loses cognitive functioning, such as thinking, remembering, and reasoning.

Link Between Air Pollution & Cognitive Health

Air pollution’s impact on cognitive health establishes a link between both. Research indicates that air pollution affects cognitive health at every stage of life. It includes:

Children

Studies show that children exposed to high air pollution exhibit lower cognitive performance. A Boston University study followed 200 children and found that those exposed to elevated black carbon levels scored lower on memory and IQ tests.

Additionally, exposure to delicate particulate matter during early childhood is linked to behavioural issues and cognitive deficits.

Adolescents

Stanford Snaplab’s research indicates that adolescents exposed to ozone pollution show increased depressive symptoms. It increases adolescents’ emotional disorders, as well as anxiety and neuroticism, and decreases motivation, leading to a decrease in the development of adolescents.

Adults

Prolonged exposure to air pollution is associated with a decline in cognitive function in older adults. A study in northern Manhattan found that participants living in areas with higher air pollution levels had lower cognitive scores and experienced faster mental decline over time.

Also Read: How Can I Contribute To The Reduction of Air Pollution?

Air Pollution’s Impact on Cognitive Health

Air pollution is a global health issue. New evidence links air pollution to cognitive health problems at all ages. This connection is especially concerning because cognitive disorders, like dementia, are on the rise.

By 2050, dementia is expected to affect about 152 million people worldwide. Understanding how air pollution impacts cognitive health is critical to creating effective public health strategies. Air pollution’s impact on cognitive health include:

1. Inflammation and Neurotoxicity

Air pollution impacts cognitive health primarily through inflammation. Pollutants like particulate matter (PM), nitrogen dioxide (NO₂), and black carbon can cause inflammation in the body. When inhaled, these pollutants can cross the blood-brain barrier. This process can lead to neuroinflammation, which damages neurons and disrupts brain function, causing cognitive decline.

Long-term exposure to air pollution can affect amyloid-beta processing. Amyloid-beta is a protein linked to Alzheimer’s disease. Inflammation can also affect neurotransmitter systems, leading to mood disorders and cognitive issues. The high pollution levels are linked to more anxiety & depression, especially in children and teens.

2. Developmental Impacts

Air pollution affects cognitive health early in life. Studies show that children exposed to high pollution levels perform worse cognitively. Boston University research found that children exposed to black carbon had lower verbal and nonverbal IQ scores. Early exposure to delicate particulate matter is also linked to behavioural problems and cognitive deficits.

3. Cognitive Decline in Older Adults

Long-term air pollution exposure is linked to cognitive decline in older adults. A review of studies found that people in areas with higher pollution had lower cognitive scores and experienced faster cognitive decline over time. A study in northern Manhattan showed that participants exposed to more air pollution had lower cognitive function and more rapid decline.

The Nurses’ Health Study found that a 10 µg/m³ increase in PM10 was linked to lower cognitive scores. This suggests that air pollution is a risk factor for cognitive decline. Reducing pollution exposure could help protect mental health in older adults.

4. Neurodegenerative Diseases

Air pollution may raise the risk of neurodegenerative diseases like Alzheimer’s disease. Studies show a strong link between exposure to traffic-related pollutants, like NO₂ and black carbon, and Alzheimer’s. Researchers are still exploring how this link works, but chronic inflammation and oxidative stress may be critical factors.

Public Health Implications

Cognitive disorders, including dementia, pose a significant public health challenge. The global prevalence of dementia is expected to double every 20 years, with profound social and economic implications. Global healthcare expenditures for cognitive impairment reached $818 billion in 2015 and are estimated to reach $2 trillion by 2030.

The intersection of air pollution and cognitive health decline exacerbates this issue. Poor air quality disproportionately affects vulnerable populations, including children and the elderly. In many LMICs, high pollution levels coincide with limited healthcare resources, increasing the risk of cognitive disorders in these communities.

Policy Recommendations

Addressing air pollution is crucial for protecting cognitive health. Policymakers must prioritise air quality regulations to mitigate pollution levels. Strategies may include:

• Implementing Stricter Emissions Standards: Governments should enforce stricter emissions regulations for vehicles and industries to reduce pollutants.
• Promoting Public Transportation: Encouraging public and non-motorized transport options can significantly decrease traffic-related emissions.
• Increasing Green Spaces: Urban planning should focus on creating more green spaces, which can improve air quality and provide health benefits.
• Investing in Research: More funding is needed to understand the relationship between air pollution and cognitive health, especially in LMICs.
• Raising Public Awareness: Public health campaigns should educate communities about the risks of air pollution and encourage local actions to improve air quality.

Conclusion

Air pollution’s impact on cognitive health is compelling and growing. It poses a significant risk to cognitive function, with severe implications for public health. Addressing air quality becomes increasingly urgent as the global population continues to urbanise.

Policymakers, researchers, and the public must work together to tackle air pollution. Implementing effective regulations and promoting sustainable practices can help protect cognitive health. By prioritising clean air, we can safeguard our cognitive future and enhance the quality of life for future generations.

Further research is essential to fill the gaps in our understanding, especially in LMICs. As we move forward, it is crucial to recognise air pollution as a modifiable risk factor for cognitive decline and take action to mitigate its impact. Doing so can protect our mental health, the health of our communities, and the health of the planet.

Also Read: How Heatwaves Amplify Urban Air Quality Issues?