Particulate matter pollution may negatively affect the brain.

Particulate matter pollution has long been known to be a factor in raising the risk of stroke. Additionally a 2004 American Heart Association scientific statement on “Air Pollution and Cardiovascular Disease” concluded that exposure to particulate matter (PM) air pollution contributes to cardiovascular morbidity and mortality.

It appears that air pollution and the negative health effects of particulate matter has one more concern to add to the list ‘risk to brain structure and cognitive functions’. A new study led by scientists from Beth Israel Deaconess Medical Center and Boston University School of Medicine suggests that long term exposure may cause damage to brain structures and impair cognitive function. Further it found that a PM2.5 pollution increase of only 2µg per cubic meter, a range commonly observed across metropolitan regions, was associated with being more likely to have covert brain infarcts and smaller cerebral brain volume, equivalent to approximately one year of brain aging.

Particulate matter pollution health effects are an increasing concern as air pollution continues to be a worldwide concern. Additional readings below of a CDC informational page supplies useful information. The link to the EPA Air Quality Index (AQI) tells you when air pollution is likely to reach levels that could be harmful. You can use the AQI as a tool to help you avoid particle pollution.

What are brain infarcts?
A cerebral infarction is a type of ischemic stroke resulting from a blockage in the blood vessels supplying blood to the brain. Specifically related to air pollution it looks that Infarcts deep in brain have been linked to poor memory and cognition besides hampering functioning of the smallest of the vessels that could lead to stroke without symptoms.

What is particulate matter air pollution?
Particulate matter (PM) is an air pollution term for a mixture of solid particles and liquid droplets found in the air. The pollutant comes in many sizes and can be composed of a variety of materials and chemicals. Particles that are small enough to be inhaled have the potential to cause health effects.

Particles less than 2.5 micrometers in diameter (PM2.5) are referred to as "fine" particles and are believed to pose the greatest health risks. Because of their small size (approximately 1/30th the average width of a human hair), fine particles can lodge deeply into the lungs.

Beth Israel Deaconess Medical Center. "Long-term exposure to air pollution may pose risk to brain structure, cognitive functions." ScienceDaily. ScienceDaily, 23 April 2015.

Brook, MD et al., AHA Scientific Statement “Particulate Matter Air Pollution and Cardiovascular Disease.” American Heart Association

Further Reading
‘Particle Pollution’ Centers for Disease Control and Prevention

EPA Air Quality Index