How Pollution Damages the Brain?

Medical science experts believe that air pollution primarily causes harmful health effects related to the lungs and cardiovascular system over a long time. However, several studies across the globe have indicated that pollution also damages the brain.

Neuroscientists and toxicologists have been researching how fine particulate matter from power plants and vehicular emissions cause adverse impacts on people’s brains.

The ultra-fine particulate matter like PM2.5 and PM10 are so tiny that they remain suspended in the air for long durations and penetrate the body. These fine particles can travel up the nose and enter the brain via the olfactory nerve bypassing the blood-brain barrier en-route.

These fine particles that penetrate the brain also carry various chemical compounds, contaminants, dioxins, and metals like lead or iron; on their surfaces.

Thus, several harmful chemicals enter the brain and act in various ways for causing damage to the brain.

Altering the Size of a Child’s Developing Brain

As per the study published in Environment International, the ultrafine PM2.5 particles may cause changes in developing brains’ size among children. This may eventually lead to higher risks of cognitive and emotional problems in adolescent stages.

The neurons in children’s brains expand and prune rapidly at a young age as their brains develop and form efficient neurological pathways. Exposure to PM2.5 particles leads to altering these pathways, resulting in changes in brain development patterns.

As per the study’s findings, the kids who are highly exposed to air pollution have smaller areas associated with cognitive functioning compared to kids with less exposure to PM2.5 particles.

Effects On Young Brains

As per the study published in the American Journal of Epidemiology, 2008, the research was carried out on over 200 Boston children from their birth to the age of 10.

This study indicated that the kids exposed to higher levels of black carbon perform badly in tests related to memory, verbal, and non-verbal IQ.

Another study conducted at Columbia University and published in Environmental Health Perspectives, 2012, followed the kids from their birth to an average age of 6 or 7.

This study indicated that kids exposed to greater levels of urban air pollutants produced by burning fossil fuels were more likely to experience symptoms of anxiety, depression, and attention-deficit disorders.

As per the findings published in Brain and Cognition, 2008; the kids exposed to urban air pollutants are more likely to have damaged tissue and brain inflammation in the prefrontal cortex. These kids are likely to score lower on memory, cognition, and intelligence tests.

This neuroinflammation caused by pollution disrupts the blood-brain barrier. It is also responsible for various central nervous system disorders like Parkinson’s disease and Alzheimer’s disease.

Chronic Inflammation in the Brain

The PM2.5 particles can carry various chemicals and metal particles over their surfaces while penetrating the brain. These particles can damage the brain’s neurons directly and interfere with the microglia function resulting in widespread harm to the brain.

The microglia are the immune cells of the brain that trigger the chemicals for killing these particles. The accumulation of these chemicals results in chronic inflammation in the brain that may cause neurodegeneration.

The smaller air pollutants can also reach the brain via the bloodstream. These particles pass through the tiny air sacs present in the lungs and get into the blood capillaries. These are circulated in the body via the blood and cross the blood-brain barrier.

When your immune system releases chemicals while considering these particles as pathogens, the chemicals trigger widespread inflammation that harms the brain.

Increased Risks of Cognitive Decline in Adults

As per the study published in the Archives of Internal Medicine, 2012, the older women exposed to greater levels of the air-pollutants experienced increased levels of cognitive decline compared with other women of the same age.

The researchers’ findings have indicated that long-term exposure to higher levels of pollution dramatically worsened the symptoms of women’s cognitive decline.

Another similar study published in Environmental Health Perspectives, 2011, indicated that exposure to high levels of black carbon in men had led to reduced cognitive performance.

As per the study conducted by Portuguese researchers and published in the Journal of Environmental Psychology, 2011, the individuals who lived in highly polluted areas were found to have higher levels of anxiety and depression.

Even though many have started using filter mask on daily basis and installed an air purifier at home, it is still important to take precautionary steps and avoid going to any polluted area.

Structural Changes in the Brain

Numerous studies have been conducted across the globe that point towards the damaging impacts of air pollution on the brain and its normal functioning.

Experiments conducted on the mice revealed that pollutant-exposed mice showed signs of depression and behavioural changes. The mice exposed to particulate matter were found to have higher levels of cytokines in their brain.

The pollutants exposed to mice also showed physical changes to the nerve cells in the hippocampal region. These mice had fewer spines on the neurons’ tips that signified less dendritic complexity and poor memory.

The alarming fact that air pollution affects our brain is increasingly becoming clear with every other study’s findings on the subject. The mounting evidence establishes a connection between various neurological problems and air pollutants.

Exposure to high levels of air pollutants results in cases of Alzheimer’s disease, increased risks of dementia for older women, autism-like social and behavioural issues in adults, and lower scores in tests for memory, attention, and behaviour.

The fine particulate matter that we inhale can directly interact with the brain and cause widespread damage. Thus, it is paramount to keep air pollution in check.

The main culprits are the PM10 and PM2.5 particles that don’t act alone but carry various other chemicals along with them. The extent of the damage that the smog in our brains can do is still being studied, and more insight would be available shortly.