Air pollution refers to a wide range of gases, liquids, and solids suspended in the atmosphere. Known to have harmful effects on the respiratory and cardiovascular systems, these contaminants are now implicated in damage to the brain—an organ exposed to the air via multiple pathways.
Contaminants breathed through the nose can come into direct contact with the olfactory bulb, a neural structure in the vertebrate forebrain. Some research in humans and other animals suggests that fine particulate matter smaller than 2.5 micrometers across can reach the olfactory cortex and other brain regions via this route.
Most gases can easily traverse the epithelium in the lungs to make it into the bloodstream, and some studies in humans and rats suggest that fine particulate matter can do the same. Circulating contaminants may wear down the blood-brain barrier and/or cross it to directly interact with neural tissue.
Pollutants that make it to the ...
