New research has discovered toxic mineral particles – known as magnetite – in the brains of people who lived in heavily polluted areas of Mexico and the U.K. The particles, smaller than 2 microns in diameter, have been linked in other studies to Alzheimer’s disease.

The new research, conducted by Lancaster University (U.K.) and published in the Proceedings of the National Academy of Sciences, suggests that magnetite can make its way directly to the brain after being inhaled. Although magnetite can occur naturally in the human brain, the size and shape of the particles discovered in the study indicated they came from a source such as roadside particulate matter. Some of the particles were smaller than 0.005 microns in diameter, making them among the smallest particles that exist.

What is magnetite?

Magnetite particles are a highly magnetic mineral form of iron and are known to be present in air pollution. Magnetite has been found in homing pigeons, migratory salmon and even bats, and is believed to play a role in their directional orientation.

In the human body, magnetite can cause oxidative stress and disrupt cellular function. The type of cellular disease that results from exposure to magnetite is consistent with cellular damage present in Alzheimer’s. For this reason, scientists believe there may be a connection, though there is no direct evidence at this point linking the mineral to Alzheimer’s.

Researchers believe the entry point for the magnetite found in human brains was the olfactory bulb, located at the top of the nose. There is no blood-brain barrier at that point of the nose, the researchers noted. From this location, particles can easily make their way to other parts of the brain.

Other air pollutants and Alzheimer’s

Though the exact mechanism by which air pollution might contribute to development of Alzheimer’s remains unknown, several past studies have found an association between Alzheimer’s and air pollutants other than magnetite.

One study, the results of which were published in the Journal of Alzheimer’s Disease in 2015, found a 138% increased risk of Alzheimer’s for every increment of 4.34 micrograms per cubic meter of PM2.5 exposure over a period of years. The study concluded that long-term exposure to levels of ozone and PM2.5 above current U.S. EPA standards are associated with increased risk of developing Alzheimer’s Disease.

How to reduce your exposure to magnetite

Since the magnetite particles identified in the Lancaster University study were determined to most likely be from roadside pollution particles, reducing your exposure to traffic air pollution is probably the best way to protect yourself against breathing magnetite. Here a few tips on how you can do that.

1. Avoid exercising near high-traffic areas. According to the U.S. EPA, the greatest concentration of traffic pollutants is typically within 500-600 feet of a major road. When exercising outdoors, try to stick with trails and less-traveled roadways.
2. Stay indoors when air pollution levels are elevated. Regularly check the daily air pollution forecasts in your area. When the air is bad, limit the amount of time you spend outdoors, especially near busy roadways.
3. Clean the indoor air. Portable or central air cleaning systems can significantly reduce the concentration of pollutants in the indoor air you breathe. For example, a high-performance air purifier such as the IQAir HealthPro Plus can remove even the tiniest magnetite particles in the air before they can be inhaled.

It’s also important to be part of the solution to air pollution instead of being part of the problem. Our daily activities and lifestyle can make a difference. For example, walking, biking or carpooling to work helps reduce roadside pollutants. Using buses, subways, light rail and commuter trains also help. For more ideas on how you can help reduce traffic pollution near where you live and work, visit www.epa.gov.