We’ve known that air pollution is detrimental to the reproductive, respiratory, cardiovascular and central nervous systems. Now, we know that air pollution negatively impacts brain health as well. Let’s take a look at all of the ways that air pollution affects brain health.
Alzheimer’s & Brain Awareness Month
Did you know that 55 million people around the world are living with Alzheimer’s disease and other dementias? Alzheimer’s is the most common cause of dementia. It is a degenerative disorder that causes brain cells to die. Other common forms of dementia include Lewy body dementia and vascular dementia. Dementia is simply an umbrella term to describe a group of symptoms such as memory loss.
So, why are we focused on these cognitive disorders? Well, June is Alzheimer’s & Brain Awareness Month. This month presents an opportunity to learn, educate and spread awareness about Alzheimer’s disease and other dementias. Everyone with a brain is at risk, hence the importance of this awareness month! And, recent research suggests that air pollution plays a part in the development of neurological disorders and cognitive decline.
What Air Pollutants Damage Brain Health?
It’s becoming more and more evident that particulate matter, in all its forms, is the primary antagonist for many health issues, including those related to the brain.
Particulate matter is classified based on size. The most well-known groupings of particulate matter are PM2.5 which encompasses fine particles that are no larger than 2.5 micrometers, and PM10 which is coarse particles up to 10 micrometers in size. The less well-known form of particulate matter is PM0.1 which is ultrafine and no larger than 0.1 micrometers.
Unfortunately, fine and ultrafine particles are extremely difficult for our bodies to combat. When inhaled, they travel along the olfactory nerve and bypass the blood-brain barrier. In short, once these particles reach the brain they wreak havoc and cause neuroinflammation. Additionally, these particles travel through the bloodstream and cause widespread inflammation, affecting the brain. And, when ingested they cause indirect neurological effects. All in all, fine and ultrafine particulate matter are the most damaging air pollutants.
Other air pollutants that cause neurological damage include black carbon (a component of fine particulate matter), polycyclic aromatic hydrocarbons, lead and carbon dioxide. All of the aforementioned air pollutants are the result of burning fuel and combustion processes.
How Does Air Pollution Affect Cognitive Development?
Research has shown that air pollution is a detriment to cognitive development. Dr. Shakira Franco Suglia and her colleagues at Boston University’s School of Public Health analyzed the effect of air pollution on children’s cognitive development. They followed more than 200 children in Boston from birth until the average age of 10. Children exposed to higher levels of black carbon performed poorly on memory, verbal and nonverbal IQ tests.
Paul Mohai, a professor at the University of Michigan’s School for Environment and Sustainability, found similar results in his study. His research controlled for socioeconomic differences and other confounding factors. Nonetheless, certain public schools in Michigan had the “lowest attendance rates and greatest percentage of students who failed to meet state testing standards.” Specifically, public schools that were located in areas with the highest industrial pollution levels.
Does Air Quality Affect Dementia?
In addition to disrupting cognitive development, air pollution accelerates cognitive decline. Epidemiologist Jennifer Weuve and her colleagues at Boston University’s School of Public Health conducted an enlightening study. More than 19,000 women across the United States, ages 70 to 81, were sampled. The women’s address history was used to estimate their exposure to particulate matter in the seven to 14 years prior to the study. The researchers investigated both fine and coarse particulate matter. The results of various cognitive skill tests indicated that both PM2.5 and PM10 were associated with cognitive decline.
Can Air Pollution Cause Neurological Damage?
Unfortunately, due to the inflammation caused by air pollutants, exposure can cause neurological damage. Dr. Lillian Calderón-Garcidueñas conducted a study that examined 55 children from Mexico City and 18 children from Polotitlán, Mexico. Comparatively, Mexico City is more polluted than Polotitlán. MRI scans determined that children exposed to air pollution were significantly more likely to experience neuroinflammation and tissue damage in the prefrontal cortex. Inflammation in the brain plays an integral part in various central nervous system disorders because it disrupts the blood-brain barrier. Furthermore, children from Mexico City scored lower on memory, cognition and intelligence tests.
And, according to this study, exposure to excessive air pollution during pregnancy may lead to “permanent brain damage or cognitive impairment in old age.” This is due to the fact that the brain structure is established during this time period. Moreover, air pollution may have a “greater negative effect on brain development” in utero than during childhood.
Air Pollution and Brain Health
Cognitive development, neurological disorders and neurological damage are three very important aspects of brain health. Air pollution affects each one. While we take the time to raise awareness about Alzheimer’s and brain health, let’s include air pollution in the conversation. It may bring us one step closer to finding a cure for these relentless disorders.