Pollution can be ugly. Just think of an industrial chimney spewing smog into the air. It has devastating effects on the environment, plants and wildlife. And we know that pollution has a negative effect on our physical health. Since the 1970s, a recent article in Monitor on Psychology reports, we’ve studied the harmful impact of pollution on our cardiovascular and respiratory health.
A growing body of evidence indicates that the impact of pollution goes beyond physical health. According to the Monitor, researchers have found that high levels of air pollution may damage children’s cognitive abilities, increase adult risk of cognitive decline and may even contribute to depression.
The issue is not as visible or taken as seriously as it should be, according to Paul Mohai, PhD, a professor in the University of Michigan’s School of Natural Resources.
How Does Pollution Affect Our Brain?
It depends on the size of the particle we inhale, says Jennifer Weuve, MPH, ScD, of Rush Medical College. Fine particles, such as those found in smoke, car exhaust and pollen, can interact directly with the brain. It is still unclear how coarse particles impact our brains.
One study exposed mice to levels of pollution similar to the exposure a human commuter might experience. It found that longer exposure led to slower completion of a maze and more mistakes.
These mice exposed to pollution also showed signs of the rodent version of depression, giving up on tasks more quickly and avoiding previously pleasurable activities.
Comparisons of exposed mice to mice that were not exposed showed striking differences. Those exposed to pollutants had higher levels of a molecule that regulates the body’s inflammatory response.
More surprising was the discovery of changes to nerve cells in the hippocampus, a part of the brain known to play a role in spatial memor. Exposed mice had fewer connections and less complexity in this part of the brain, a situation usually connected with poorer memory.
Human studies also are showing cognitive impairments with pollution exposure. In a study that included more than 19,000 women, Weuve and her colleagues found long-term exposure to high levels of pollution worsened the women’s cognitive decline.
In a similar study, Melinda Power, a doctoral candidate in epidemiology and environmental health at the Harvard School of Public Health, found men exposed to high levels of black carbon (used to measure traffic-related pollution) had reduced cognitive performance. In fact, the pollution appeared to age them, cognitively, by two years, as compared to men with less exposure.
Mental and cognitive effects of air pollution are now beginning to receive attention in the mental health research community. There is still much to learn.