According to a study published in PNAS, breathing in toxic air could lead to brain disorders and neurological damage as the particles are potentially transported from the lungs to the brain via the bloodstream. The researchers revealed that the particles stay longer in the brain than in any other main metabolic organ.

Air pollution is a cocktail of many toxic components, but the particulate matter is the most concerning component as it is associated with the highest number of detrimental health effects. Particularly, ultrafine particles can escape the body’s protective systems, including sentinel immune cells and biological barriers. In the study, the researchers found various fine particles in human cerebrospinal fluids taken from patients who had experienced brain disorders.

The researchers from the University of Birmingham and research institutions in China explained that inhaled particles can enter the bloodstream after crossing the air-blood barrier, which eventually reaches the brain. These inhaled particles cause damage to the brain-blood barrier and surrounding tissues. Once in the brain, the particles are hard to clear and are retained for longer than in other organs. 

(Source: https://health.economictimes.indiatimes.com/news/diagnostics/study-inhaled-toxic-particles-take-direct-route-from-lungs-to-brain/95381938 )