For years, it has been common knowledge that air pollution can harm one's cardiovascular and respiratory health, increasing the risk of premature death from heart and lung diseases. However,  researchers are now finding that smog may also be harming your cognitive abilities. Over the last 10 years, studies have shown that high levels of air pollution may damage children's cognitive functions, as well as contribute to the decline of cognition in adults.

Type of Pollution

The majority of the research on the effects of pollution and cognitive ability focuses on a specific type of pollutant know as "fine particulate matter", which is 1/30 of the width of a single human hair. Particulate matter is dispersed by power plants, trucks and cars by way of smoke, car exhaust and even pollen. According to Jennifer Weuve, MPH, ScD, Assistant Professor of Internal Medicine at Rush Medical College, due to the small size of the particles, they can easily penetrate the body's defenses and are able to cross from the lungs into the blood, sometimes travelling up the axon of the olfactory nerve towards the brain. Coarse matter does not have the same ability, and is therefore much less dangerous.

Changes in Your Brain

Randy Nelson, PhD, Professor of Neuroscience at Ohio State University conducted an experiment using mice that showed that changes occurred in the brain due to the exposure to fine particulate matter. To  mimic the life of a commuter who lives in a heavily polluted city, Nelson exposed the mice to high levels of fine particulate matter five times a week, eight hours a day. After 10 months, Nelson discovered that the mice that had been exposed to the pollution took longer to complete the maze task and made more errors than mice that had not been exposed (control group). The pollutant-exposed mice also showed signs of the rodent-equivalent of depression. When examining the brains of the exposed mice, Nelson found increased levels of cytokines in the brain. Cytokines are molecules responsible for regulating the body's inflammatory response. Physical changes in the nerve cells were also found in the hippocampus, the region responsible for spatial memory.

Who's at Risk?

Older women that are exposed to the pollutants are found to be more susceptible to the cognitive declination than women their age who are not. Also, research provides evidence that air pollution can harm children's cognitive abilities. A study at Boston University found that kids that were exposed to greater levels of black acrbon received lower scores for memory, verbal and non-verbal IQ tests than unexposed children. Furthermore, a study conducted in New York City found that children who were expsoed to higher levels of air pollution while in the womb were more likley to develop attention problems, as well as symptoms of anxiety and depression after birth.

What Can You Do?

Unfortunately, there is not a lot that you can do to protect yourself from exposure to fine particulate matter, apart from wearing special masks, or installing a filtration system in your home and office, or moving to a city with less airbourne pollution. However, the mental and cognitve effects of air pollution are now beginning to receive attention from the mental health community, and awareness is the first step in prevention.