Why Is Air Pollution So Bad for Your Brain?

Air pollution can impact brain structure and reduce cognitive function.

Posted Apr 24, 2015

Source: Arlens/Shutterstock

Global warming and pollution are not only wreaking havoc on our planet—they're also wreaking havoc on our health. Air pollution has long been associated with health problems including respiratory ailments, asthma, and an increased risk of stroke. New findings show that air pollution also damages the human brain.

A new study by scientists at the Beth Israel Deaconess Medical Center and Boston University School of Medicine found that long-term exposure to air pollution can damage brain structures and impair cognitive function in middle-aged and older adults.

The April 2015 study, "Long-Term Exposure to Fine Particulate Matter, Residential Proximity to Major Roads and Measures of Brain Structure," was published in the journal Stroke.

The researchers unearthed evidence that air pollution impacts brain structure and could cause a type of "silent" ischemic stroke which led to a blockage in the vessels that supply blood to the brain.

The study evaluated how close the participants lived to major roadways and then used satellite imagery to assess the relative prolonged exposure to ambient fine particulate matter. These particles in air pollution come from a variety of sources that include: power plants, factories, trucks and automobiles, as well as, the burning of coal and wood.

The fine particle matter in air pollution can travel deeply into the lungs. Previous studies have linked exposure to air pollution with an increased number of hospital admissions for cardiovascular events such as heart attacks and strokes.

Source: Trekandshoot/Shutterstock

Air Pollution Can Impact Brain Function Throughout Your Lifespan

A broad range of studies have found that poor air quality is bad for your brain regardless of your age. A March 2015 study, "Association between Traffic-Related Air Pollution in Schools and Cognitive Development in Primary School Children: A Prospective Cohort Study," found that air pollution can hinder a child’s cognitive development.

The researchers measured three cognitive outcomes (working memory, superior working memory, and attentiveness) in 2715 primary school children from 39 schools. They found that children attending highly polluted schools with a similar socio-economic index had lower cognitive outcomes, even after adjusting for other factors that can affect cognitive development. 

The findings suggest that the developing brain is vulnerable to traffic-related air pollution well into middle childhood. Hopefully, these findings will influence policy makers and encourage more air pollution regulations and less-polluted locations for new schools.

A November 2012 study from The Gerontological Society of America found that living in areas of high air pollution can lead to decreased cognitive function in older adults. This was the first study to show that exposure to air pollution influenced cognitive function in a national sample of older men and women. 

The researchers found that fine air particulate matter—composed of particles that are 2.5 micrometers in diameter and smaller—can deposit itself deep in the lungs and possibly the brain. The authors conclude that air pollution may be an important environmental risk factor linked to reduced cognitive function in old age.

Conclusion: One More Reason to Park the Car and Ride a Bike

Even if you and your family live in an area with high pollution, a March 2015 study from Denmark found that physical exercise can outweigh some of the harmful effects of air pollution, in relation to the risk of premature mortality.

Physical activity can increase respiratory intake and the amount of air pollutants that you're breathing into your lungs, which can increase the harmful effects of air pollution during aerobic exercise. If it's possible to exercise indoors—or get to a park, river, or wooded area with less pollution on days when air quality is particularly bad, you should try to do so. 

Scientistists funded by the European Research Council are using smart phone technology to track air quality in different neighborhoods and pinpoint where and when air pollution is worst. Air pollution can vary widely throughout the course of a day and time of year, even within the same city. 

Hopefully, mobile technology will provide a way for people to know when local pollution levels go up and down so each of us can time our outdoor physical activity accordingly. 

Please use common sense when exercising in smoggy environments. That said, even if you live in an urban area and air pollution seems like a barrier to exercise, remember that the detrimental impacts of being inactive outweigh those of breathing air particulate matter.

If you'd like to read more on this topic, check out my previous Psychogy Today blog posts: 

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